LOONMEvlE_ESE_E҈EEE E֘EEE$E}EEbFEEbjEEyE*EEEEEEEE`EEaTE{EaxEbEaEɋEEEEόEEϿER\EgEqEEqE?EEeEE\EuE{*EfE,EsEHEEHE^EI}E3E@E3EEPEE/E"7E/E +E,IEEEѿEEn>EEoE6ElcE EljEcE>E#E> E_GE>E$E>EE>E^E?@E6CEPEFiEE"EEEIE$E EEwE(EfEEEעEEEtEwEEugE EEEEeE@EeEfEeEEjLEEjMEEVE2E{E> EE,EE:E,E;EYE"EAEEAEEgEEE9E?EEE=EWE>E1E@EE@EE@EE]E E!EedEEhE.EhEEYEEEՁEEEսEGEEGEoEE\E>9EE>EE=EEGqEEE^EnEQE,E,wEEE9vEJE96EJE-{E EXEEXEE EEq?EE[EEE/E ESmEECqE,{ECrE,dEEPEEDEE E=EEcEEjE35EaLE4EE4E$ EmEqEE{E$wEE$pEEJDEEJHEENEE~zEEeEEjIE*EgEڝE[E2EE2EElEElEElEEGEE#E{uE xE{EJEa*E@E#ESEE6EERExNESExrEBE pEYEWE"EPE>#EtE>E{EEOE XE,E YE,E}#EREmE|EE}EE~E!EkE>ME EEEEEEEEEESEbEEBEEmEJEmEDEQE&EEEEKEEaEEEEEEE EEEEcE>EE;E|E8E}EVEEET EEr)E0EEoEEEbEEnEgEEgEE9mEEvEBEbUEEbEEbE4E Ej EgEj E~EE~EmEPEE}KEE[EEeEdElEEYEEEE8EE9TEE9UEE EOE EE2pEEixEEinEEi E-xER8EhaEREEREϷEREϰE^EEEEEEEEEpEr,E8Es EEEqkErEEOEmEEOvEEbEEbEtEbEEbEkEE)EVEEEEEEEE3EEZEEEE EDE`SEEd|EE\EE]rE EI6EExE}ExE EE#EܮE#E6EkBEVE'E3E'EZE'EZE)E/E1E(E2EOEnEȅEnEȳEoNEȼEEE!EHEkEIEWEyETEETEEdVEE4EE'E~EzEdEE;gEERBEER|EERiE9E`E}E1E~EEQEEFgEoErE ErEE(EQE2EdEEeAEEdEL E.2ExEEbEmEbE'EbEEbE'E/EWEE]EdEޮEnEPEoE]EUE]EEEE1E E>EAEEEE%EEWEE EEELER ECEmEaE/EЯE(EEEE-EehEPECEkE3EEE.E>EGEEEEфExhEE~EEFEpgEڎE}EE} EEGEEGEE]EEEEEUE PEUE;EE;E E4E< EEE,EEENEEEjEE=QEE=REEdWE~EdE EdE/UEE/E'EEEOeEEO"EEpEĉEqvE"EqE"Eq EAE+ECEEE(EEGJEEGKEEG>E/(EqEiE~EE~Ea E~Ej~E~EEEEuEEEEE^EEEEEEdE{EaE&E3EgEEEEE /EME7E(E(EEE:EӣE =EE EE7EuE7E E7EME7E:E4qE8 E=EEErEE`ESE>4E(ZE=KEkElEEEbEJqEuEGEEGEEpEEqCEEIEEmELE EEyE7E(EJE.4EEx/ESE4ETgEETE/ExEE!EEEEEE=uER_E"EQE"EPE!EE!EE!EFElEpE EE0~E E0E=EjEpEEE'ETEEUREEyEOEEvEEE$UEZE$xE5E$E5EYE>E^cEVE^-EE9EF|EEF}EEaEEf|E#E`DE2E`iE~E*E EEEEAE?pEEEEEXEYAE$jEE$*EsE$E6EEEɤEEE:E]E:&E8EH*EodESEo$EaEVE3E_E1$EuEt\EETE EEuE~E~EEoE#E/EėEW/EEEtE5lECE5 Ek%E-ESEp%ErEtEE$EEbE$EEWwE_EEEEEEE EeE7BE%EEEĝE]E'EoEоEsE EEEEEEE*ERE(ER>EEi>EÚEo,EäE4E; E^yEKE^EoEL|E@&EE7EE@&EE@EhE:3EQRE:cEE:"E,E:E,E:EWEETEE+EEuJEEumEεEE&EƓEEE'WEESEES'EdE"EdEKEdEEe[E E"E7E>E79EOEEhEщE=EEmodn.lst -l modn327 addressing modes supported 312debug=fullflush option 74 for (; d < 10.0; ++d) -m optlon 295undefine command 94, 191 See hypergst utility syntax and description 237_238 macro procedure. End the macro definition with the ENDM directive on chapter, describes how to specify each type of constant.313 Using Assembly Language with C Language (An) add.w (a1) ,d0 XREF label[,label]. . . You can define symbols to be in the data section by USillg XREF and XDEF after the SECTION directive. The following exarnple uses 16-bit addressing to reference both code and data: SetFunction 114 options 289-290 greater than sign (>)host machine 6, 96 .SET fake target 282-283multiple targets 283 setenv command 11-n option 290 char lefty; double middle, int mrright; 264variables defining with equals sign (=) 277-278terminating tasks 108 overriding definitions 278trap handling 113-114 referring to macros 278 types of tasks 108 Map Options window 267 -m0 option, asm command 325 MASK2 assembler directive 306-m2 option, asm command 325 parameters=register option 318-319 prev command, SC_SCMSG AREXX port d16 a 16-bit displacement examples 1 73 SC_CPR 101 running go command before using 30See also AREXX macros See SECTION assembler directivedebugging applications 99348 Index Constant propagation is often useful in programs that contain break command 48-53 surrounding character strings 19 errors and warnings, searching forSee smake utility See scmsg utility file-matching algorithm 341-342 option results command (AREXX) 103beginning AREXX templates 261 optionsspecifying binary numbers in assembler See also command-line options absolute addressing modes 313aliases for dump command in previous absolute expressions 304 releases 146 147 accelerator keys 23-24, 29, 34alternate targets, smake utility 283 284 actions gadget 267262 activate command 107, 111, 127altline command, SC _ SCMSG AREXX Address field, tasks command 109 port 262 changes to addition loops containing multiplications (usually those You can address the arguments from A7 as follows: (A7)+8+n8argument middle (A7)+16+n4argument mrright Using the parameters=register Option Using the parameters=register option tells the compiler to pass some of the function arguments in registers instead of on the stack. Specifically, the first two pointer arguments are in A0 and A1, and the first two integral arguments are in D0 and D1. All other arguments Break menu 21 22320-321 breakpointssaving register contents 317-318 defines a program unit name. quitting the debugger 10, 34altering contents 67-68 trace option, break command 51, 52 53,-w command line option 80 filename. If you specify a directory name as a prefix, include the (/). itself. After the MACRO directive, enter the lines that constitute the size 300support for escape characters 123 dynamic by default 70XDEF assembler directive 308 The compiler identifies functions that expect arguments in registers infinite loops 112See oml utility y = (i + j) * 2; inserts a page break into the listing file. assembles if the expression is greater than or equal to 0. by placing an @ in front of the function name. The @ replaces the maximum bad characters -m3 option, asm command 326 compiler options, settingstarting the kernel 98 list option 86stepping over code 29-30 -screen command-line option 80 Sscratch registers 318 See peephole Optimizer peephole optimizer 329 for (i = 0; i < n; ++i) NotationMeaning is included for compatibility only. __MERGED for near data. You can use a specific name only commands for running sampledelete block, diff utility 220 bne.b noadd ; no, check subtract can be changed to The effect of global optimization's register allocation is quite in the following function call, the compiler generates code to push the arguments mrright, middle, and then lefty onto the stack. search option, opt command87-88, 166 addsym option 8, 9 Qdetermining variable values 77 altering register contents 67-68 See also fregister command break command 48-53, 135 136functions assembler statement size suffixes 302 See calling C functions from assembler See also bclear command C mode 83 SET assembler direetive 307 local input files 284 286 set eommand 177 178 macros 277-281 ; (semicolon) EQU assembler directive 305 fake targets, smake utility 281-283 Using Macros," describes how to define and use macros. MASK2 instruction bytes-line command-line option 11, 79 See ibytes option, opt command line parameter, location parameter 41 Mode Example See semicolon (;) Istat utility 244 248task option, opt command 107, 110 111, Step Into ResLib option167 See reslib option, opt commandtasks dead code elimination eliminates code that never can be executed. common subexpression merging the parameters=register option or use the __asm keyword, C copy propagation -nok option 98 OpenLibrary function 114 * Heckel, P. (1978), "A Technique for Isolating Differences Between Files," Communications of the ACM (April), 264-8.342 Appendix separating multiple arguments in display entering on command line 16-19 The algorithm will fail to match the blocks of xxx lines because it does prevents the specified segments from being loaded into chip- However, the algorithm frequently cross-matches single lines or two blocks of lines. That is, lines L and L+k may be matched to lines L1 and L1-j. Consequently, after the process described previously is completed, the matches must be untangled to generate a coherent setting 27-28, 83-84 displaying 30-31, 57, 59-60 start command 181-182 -t= option, lstat utility 244, 245-248 See also restart command target files, smake utility 273 -dsymbol [ =valuel defines symbol as if your source file contained this statement: symbol EQU value syntax 39 Help menu 16 reslib option, opt command 88-89, 167 automatically 8 restart command 172-173debug=symbolflush option 9, 25 compared with start command 181 link option 9 You can specify the displacements, data, and numbers in decimal, hexadecimal, octal, or binary format. The information on entering cmpi.b #'-',7(a7) ; should I subtract? the sc command as follows: sc parameters=register test CSECT directive 310 314 backslash character (\) Mode Example options supported 324 326 special symbol in smake utility 277 s option 326 specifying octal numbers in assembler go command 39-44, 156-157 unload option 238 CSECT statement, you can use a standard JSR instruction to a 4-byte sc math=868881 test communicating with C language 314-323definitions 92 93, 141 control sections, defining 309-314 referencing aliased commands 92 expressions, specifying 302 304continuing lines in aliases 90 AREXX port 264syntax 273, 289 SigWait field, tasks command 109-t option 290 .SILENT fake target 283 terminology 273 report of the differences. Therefore, the diff utility cross-matches The x can be one or more of the following: file. The title can be no longer than 40 characters. same asm, sc, and slink commands as shown in in the section in the section "Passing Parameters on the Stack." You also use the "Passing Parameters on the Stack." 135-w option traceback information, displayingasm command 326 See tb utility diff utility 220362 Index Low|work area | [] Sweep downward into the first file. Each time you come to a line L that is already matched to the line L1 in the second file, examine the next line. This second line is referred to as L+1. [] If L+1 is the same as the corresponding line L1+1 in the second file, then match those lines as well. return code in the ret variable. defines offsets. To define a table of offsets using the DS directive, you use the OFFSET directive. To end an offset section, use a had specified -dshortint= 1. invoking 250unassemble option 86, 167 I command 252 opt env command 112356 Index go command 26, 39-44Diagnostic Message Options window 266 online help 26-27echo mode 84 = (equals sign) induction variable transformations 331running the debugger on optimized code P[i] = f(); 334 Chapter 12 -m3 turns off the warnings generated by the -m0 option. Use this option instructions and C source lines in the source window. Use the assembly language code to determine if the variables you examine are actually located where the debugger thinks they are.338339 File 1 File 2 defining communications parameters 97See structures, displaying examples 99 DC assembler directive 305 See less than sign (<) + (plus sign) JSR cfunc;call function ADDQ #8,A7;restore stack ptr MOVE.LD0,ret ;save return value PLEN n example 106sc.examples drawer 25 libraries.cpr AREXX macro 106saving option settings in scopts utility limitations 106268-269 setting breakpoints 105sc command various control flow transformations -o option 219syntax 61, 145 parameters 202 CNOP assembler directive 304 Global Optimization and the Debugger is included for compatibility only.307 Using Assembly Language with C Language void main(void) { char lefty; double middle; defining assembly language macros 308exception hand0ing 113-114 escaped macros not expanded 92-93opt task command 110 111 optimizing 329-330 tb utility 295 saving contents before retrievingsample CodeProbe session arguments from stack 317See CodeProbe sample session comment lines, cprinit file 82examples 81-82 temp option 52-53, 135 passing parameters on the stack 315 asm command 326 devices option 88, 166 | return address | break command 48-53syntax 93, 141 error messages to that file. SECTION__MERGED,DATA syntax 46, 169 lstat utility 244 See also define command detach command 111-112 Pri field 109 U finding specific tasks 112 If you are not using registerized parameters, follow these steps: address parameter 118-119ampersand operator (&) { By default, the assembler loads the segments into memory not instructions. If you find additional patterns that the optimizer should StackPtr field, tasks command 109smake utility 290 after optionargs command 130 INCLUDE directives. You can enter up to four -i options. The screen. The listing displays the appropriate location counter and underscore (_) that the compiler normally places at the beginning of See also cprinit file quotes, double (" ") assembler statement expressions 303syntax 98 See scopts utility terminating 99-100 individual registers by separating each register with a slash wclear command 34, 194 referencing global data 322-323 -wdialog command-line option 81using with CSECT directive 311-312 caution when using variables for rangessmake utility 290 71 stripping debug information 96 For example, the following command assembles the file named modn.a, produces an object file named modn.o, and generates a listing file named modn. 1st that lists the source code and any error messages: smake utility 290special keys 23 asm command 325 menu accelerator keys 23 24, 29, 34 -i option 17-18 ibytes option, opt command 84 85, 166 IDNT assembler directive 305 IF assembler directive 305L IFC assembler directive 305 IFD assembler directive 306 l command, oml utility 252 See caret (^) w OptiOII 326 333 optrdepth -v option 291 acopyd0,a5 combine these object modules into an executable file, called a load ;this program. xdef _func exits the macro expansion. This directive is a synonym for MEXIT. FAIL Passing Parameters on the Stack small cost in time for every loop that is not executed. There is also equal to 0. When optloop has been specified, there may be a labels from other modules and from routines written in the C language. references an external symbol defined with the XDEF directive. Defining and Using Macros MOVE.L VAR1,D0 Running the Assembler multitasking features 4-5 -i 79 Using the __asm keyword on a function prototype or definition tells controlling 8 extending commands across lines Next, the func module is called, and the return address is pushed onto the stack. Figure 11.1 shows the stack after the func module has been called. if 68030 instructions are allowed. optimization creates a constant of the correct type. If the variable is optloop. the parameter placed. rts defines a constant block in memory. Using the DCB directive is [label] DCB[.size] n,expression quit command 170 registers See environmentfiles required 96 statistics utilities task addresses 111 Iprof utility 242-243task ID 110 stepping through codeSee also multitasking programs, See program execution, controlling debugging strcat function 208 displaying current task 89 strcmp function 209turning task catching on or off 89361 Index | | <-- A7+n Using the parameters=register option is similar to passing parameters using the stack. For example, make sure you: See at sign (@) {} (braces) ' (single quotes) setting on structures or arrays 71referencing global data 322-323 LocationSizeContents program counter-relative addressingsurrounding character strings 18 optimizing codeSee grep utility See global optimizerpausing 179 optloop option, global optimizer 335-336 definition 29, 39 optrdepth option, global optimizer 336examples 47, 168 336 Chapter 12 SECTION TEXT,CODE . parameters=register option 318-319extending commands across lines 18 register-direct addressing modes 313AREXX macros 101-104 when clause 42 44, 156 hidden option, scmsg Project menu 258 returning values to calling function attaching actions to 50 53 stack, example 317 return; } used only as a constant, global optimization eliminates the variable entirely. The following example demonstrates these optimizations: assigns temporarily the value of the expression to the symbol SPC n label REG R1[-R2][/R3 [-R4]] . . . assigns permanently the register list to label. You can specify (R1/R2/R3), or you can specify a range of registers by specifying (R1/R3-R5/R7). The assembler translates this list into the register ReturnLength sends a listing of the source file to the standard output, usually the badchar option 87 autoswap mode 88 Dcase option 85 . dir= option, cover utility 217 disassembling object modules (omd utility) E 249 Technique for Isolating Differences Between Files by P. Heckel.* The matching algorithm described by Heckel is simple, fast, and -c option 225 hunks command 159 error messages 234 236 hyphen (-) examples 227 specifying range in grep search 226353 Index LLEN n sets the number of characters per line in the listing file. n can be IFGT expression opttime type specifies the type of section. A value of 0 indicates a code Calling Assembler Functions from C Functions moving invariants out of loops specifying in oml utility 252-253changing the default environment 11 INCLUDE assembler directive 306 libraries, managing comment field, assembly language source cprinit file line 301 comment lines 82 global optimizer (GO) immediately above the 4-byte return address in the stack. For example, command command line option 79expression parameter 120347 Index using 110 111grep utility 225 optalias option, global optimizer 335 smake utility 290 but it is modified to use the __asm keyword. Returning Values to the Calling Function Your assembler module should return values in one or more registers. The register(s) depend on the data type of the calling function. examples 118-119 identifying addresses 118 using with location parameter 40 using with global optimizer 330 overriding default format 57SC_SCMSG AREXX port 262-264 indicating macros 277, 278representing state of the machine 14 positional parameters in aliases 90, 128 run environment 6 prefixing register names 119 user environment 6351 Index asm command 326See cprinit file grep utility 225See profile scripts oml utility 253 scsetup utility 9, 271-272 smake utility 290search command 176359 Index search path 87 88generating H_SYMBOL hunk 8 searching for expressionsstripdebug option 77 See grep utility smake utility 273 290 searching for patterns -a option 289 rulming the assembler 323-326bclear command 131 nooptpeep { i = 10; cases where it previously would not have been. For example, the optinline option, global optimizer 335functions 334 generating H_SYMBOL hunk 8values returned from CodeProbe which statements are executed more heavily, it can use the loop { config= option, scmsg utility 255option 96 clearing 34tb utility 295 moves a calculation in a loop, whose value is the same on each 32-33dumping 62-63 -hx If you are using registerized parameters, follow these steps: utility. The algorithm used by the diff utility is described in A skips n blank lines in the listing file.308 Chapter 11 grep utility 225 r command 252 See whatis commandradix option 86, 167 rsize of 4, the assembler uses absolute addressing. If you removing all aliases 92using in cmd_list parameters 50 345 Index the compiler to pass parameters in specific registers. iteration, to the outside of the loop. For example, the loop task addresses 111 -p option task-lD argument 110 diff utility 2Z0 optcomplexity option, global optimizer 335 PAGE assembler directive 307 optdepth option, global optimizer 335parameters=register option 318 319 addressable by custom hardware, if it is available. This action325 Using ~ssembly Language with C Language determining address 112-d option 289 select command, SC_SCMSG AREXX port default (.def) files 287-288 Special Characters @ (at sign) modify the variable's value in memory. The same condition applies to an external variable because it may appear in another function or the & operator may be used with it elsewhere. different from the use of the register storage class. In general, a variable declared using the register keyword is associated with a return a pointer to this object in the D0 register. The calling function definition 304 using 76 You can define a macro using the following sequence of directives and instructions: data2DC.L20 If the assembler module returns a structure or union, it must define optinlille option 335patterns containing special characters, optinlocal option 335 specifying 232 234 optloop option 335-336-q option 225 you want to assemble. The assembler assumes a source filename extension of .a, and it produces an object file with the same filename but with the .o extension. You can then use the linker, slink, to324 Chapter 11 a line by itself. You can use the EXITM directive within the macro procedure to exit the macro before the ENDM directive. RTS afunc JSRcfunc(PC) XDEFafunc Type (Bits) Syntax Meaning For example, the following code calls the function cfunc with two host machine 96 DCB assembler directive 305 XREFcfunc __asm keyword 319 320 autoedit option, scmsg utility 255 Currently, the peephole optimizer optimizes 22 patterns of assembler clearing watches and watch breaks 34 ; NOTE: This code assumes that you have a math co-processor. examples 136calling assembler functions from C displaying register contents 67 macros, smake utility 277-281 synchronous tasks 108 variables, temporary values, and constant values should be assigned assembler directives 304-308autoswap mode 29, 88 [] use the same asm command to assemble your assembler code. [] use the same slink command to link your C code. Using the __asm Keyword passing parameters on the stack 315-318 interpretation in character strings 19, referencing global data 322-323 123 auto variable elimination and remapping optimizer avoids incorrect exceptions regard0ess of the setting of defines the maximum level of recursive function calls to be inlined. } % (percent sign) the _\ts_inline keyword. machine register throughout the entire block in which it is declared Appendixdiff File-Matching Algorithm yyy zzz ; NOTE: This code assumes that you have a math co-processor. ;If you do not, your machine will crash when you run ;this program. minimal. In addition, this algorithm must first seed itself by identifying lines that occur exactly once in each file. Therefore, this algorithm may fail to match any lines even when there is an obvious match. location parameter forms 40 42 H_DEBUG hunks 7, 8 fadd.l 16(a7),fpO ; add 'mrright' to 'middle' go command 40 42, 156See pull-down menus image parameter 42, 120merge option, cover utility 217 OFFSET assembler directive 307rangelen option 87, 167 omd utility 249reslib option 88 89, 167 oml utility 250-254search option 87-88, 166 chapter. disables typebased aliasing assumptions. If optalias is used, the Run menu21 saving option settings 268-269 ModeExample -r option 295underscore (_) Appendix diff File-Matching Algorithm optsize option 336-s option 225 opttime option 336single character, specifying 228 single stepping through programs 29,-u option 290 NOLIST tells the assembler to stop producing a listing file. sets the number of lines per page in the listing file. n can be any list mask format used by the MOVEM instruction. [label] RORG n sets the program counter to n bytes from the start of the current relocatable section. [label] SECTION name[,type] function names. single quotes (' ') around 19 floating-point instructions string parameter support 123 assembler statement size suffixes 301 go command as last command of cmd list functions 314-321 parameter 51 __asm keyword 319-320 splat utility 291env option 112 Object Module Disassembler 249examples 167 Object Module Librarianibytes option 84-85, 166 Refer to the explanation for optloop later in this chapter for more information about this type of optimization. bra.b exitpoint; ready to return defined. The rtype and rsize parameters define how to access the external address. double (IEEE) 64 D0.L,D1.Lhigh bits in D0 list of functions 203 135 expressions with a different type (for example, if an int variable is The test program will pass parameters on the stack. When you run test, you should see the following output: if (expression number parameter 121opt command 82-89, 165 167 numeric keypad modes 17 arrdim option 86-87, 165 fields in source line 300-301 Control-\ for terminating oml 251 format of source lines 300escape character in grep searches 227, macros, defining and using 308231, 232-233 options supported by assembler 324-326 escape character preceding semicolon 93 previously within the same function. For example, the following starting 25 34setting up in Workbench screen 11 -s option 295 replaced by @ sign for compiler 318 tells the assembler to stop inserting page breaks and title headers in go main command 26, 80 hidden option, scmsg utility 255 commands 19flags, modifying See oml utility ignorepath option 85, 166 a[i]= temp; optimized code, rumling debugger on pass count 7, 40, 42 the variable is unused because of previous optimizations. used. The assignment can be eliminated as in this example: See also bdisable command-c option examples 68-69, 197 -z option, Istat utility 244 bra.b exitpointfrom 'middle' syntax 294-unit command-line Option 97 size suffixes, assembler statements 301-302 source command 78, 180 coprocessor is present, four floating point registers for the use of illustrations 26global symbol information 8 windowing interface 12-16 -startup 26, 80 The range is 0 to 6, and the default is 1. line mode 11-command 79 optsize option, global optimizer 336 integer parameter 47 memory configuration: size field, assembly language source linesmake.def file 287-288 300smakefile 273 slash (/)source file xdef _func -I option 219ranges, dumping 62-63 language, you can run the Assembler by entering the asm command as After you have created your modules or programs in assembly The size depends on whether you specify the shortint compiler OptiOII. A char As previously stated, C functions pass parameters on the stack if you do not specify the parameters=register option or use the __asm power of 2. For example, an alignment of 1 means that the section will begin on an even address, and a value of 2 means most are. Some types of code may cause an exception, for example, division by 0. For this reason, the global optimizer restricts moved code to sequences of instructions with shorter, more efflcient sequences. environment variable (sc/cprpath) 11FAIL assembler directive 305 equals sign (=) file command, SC _ SCMSG AREXX port example 169lprof utility 242 public screen, specifying 80omd utility 249 public symbol 250oml utility 251 very busy expression hoisting moves an expression that is computed along all paths from a point in the code to a single, common location. For example, the code defining macros in smake utility 277-278 263 (usually the entire function). In most functions, the variable is 328329 void f(double d) for (; d < i; ++d) opt source asm command 46Output window 15 opt source mixed command46, 77, 84, overwrite editing mode 17 336 escape characters 18-19 File menu TTL title only used in a comparison with f loat variables), global setting 46, 83bottom command, SC_SCMSG AREXX examples 314 using in grep patterns 227 The following sections describe how to call assembler functions from C functions and how to call C functions from assembler modules. The assembler expands the macro as follows: debug=line option 75 restart command 26 -b option 219compatibility aliases 146-147 char 8D0.Blow byte of D0 call command 137-138 Using the ampersand (&) operator with a variable prevents the global optimizer from allocating that variable to a register because it cannot predict when the resultant pointer will be used to read or heavily used in some places and not used in other places. Yet, if a machine register is assigned to the variable, then the same register disables optimizations that might sacrifice time to save space. The creating 33using with CPRX 99 function 69-70 defining symbols in data section 309 -wb command-line option 11, 80XREF assembler directive 308 diff file-matching algorithm 341-342 ASCII option 65-66 103config=option 255 [] passing parameters by placing them on the stack. Unless you specify alias command 19 Line and Find Current Line items 20 backslash (\) in character strings 19menu items and command-line backslash (\) in grep searches 227 equivalents 20-22 character strings 18-19finish command 100, 154 double quotes (" ") around 18-19 See rflag command dumping with ASCII option 66float option, dump command 64 exception hand0ing 113-114 floating-point numbers memory not addressable by the Amiga system's custom hardware. b bss or uninitialized data c code segment d data segment noadd: Guide, Volume I: Introduction, Compiler, Editor. directives up to a depth of 3. LIST addressable memory even if no other memory is available. This int func (char lefty, double middle, int mrright); optloop assumes that loops have multiple iterations when the number of iterations is variable. This assumption enables the movement of safe The lefty argument is placed into register d0, the middle argument temp = i * m; functions 15 for (j = 0; j < m; ++j) nested breakpoints 52 x command 252 NARG assembler directive 306 -v option 253 networks -x option 253 action could also prevent programs from running if external high- setting up new projectsoverriding macro definitions 278 See scsetup utility -p option 290 second character in Dialog window's title specifying location 77-78 moving invariants out of loops 331 336-337 Iprof utility 242 243 setting 83-84 Istat utility 244 248module 7 -f option 244 module parameter, location parameter 42 restoring previously saved options in scoptsscmsg utility 255-265 Part 4 See also specific directivesautoswap option, opt command 88, 165 assembly language 299 326 memory addressable by the Amiga system's custom hardware. You should specify -c for screen image and audio data. The x can be scmsg utility Project menu optionsPri field, tasks command 109 257 258printing expressions IFEQ assembler directive 306-l option bar 17 source line fields, assembly language sleep command 179 300 301 slinkcomment 301 [] After this downward sweep is completed, sweep upward in the first displaying variable values and types 32 detach command 111-112, 142 wait option, scmsg Project menu 258 where command 110, 198 that the section will begin at an address divisible by 4. Note: This parameter is not used on the Amiga. All sections are long-word aligned. m lists additional data generated for source lines that camlot be listed beside the original source line. This option allows odthe 32 bit outer displacement Xnan index register (a0.w--a7.1) xxx any number in decimal, hexadecimal, octal, or binary format inlines small functions (as defined by optcomplexity) as well as (An)+ add.w (a1)+,d0 See splat utility actions performed by 274 watch breaks 32-34window command 199 bne.b nosub; no, exit with error 340341 Watch window after clause 42, 156 verbose option238 file must correspond exactly with the lines in the object code file. The previous code can be changed to the following: executing until variable changes valuedevice command-line option 97 each mode. The notation used in these tables is as follows: rexxonly command, SC_SCMSG AREXX rexxonly option 256 Project menu, scmsg utility 257-259re-attaching tasks 112 The SAS/C Macro Assembler does not assume any default control the default. Specifying both opttime and optsize may result in When you use __asm, the calling C function places the parameters inline functions since one or more parameters to the inlined opttime option, global optimizer 336 syntax 46, 168357 Index safe operations, including integral and pointer arithmetic other than defines the maximum depth of function calls to be inlined. The IFGE assembler directive 306 diff utility 219 forcing 31]quotes, single ('') Figure 11.1| Bottom of Stack | analyzes the intermediate code produced by the compiler, performs several types of optimizations, and produces output in the same - (hyphen) See hyphen (-) - (minus sign) See minus sign (-) , (comma) See comma (,) opening 335x command, oml utility 252 specifying start-up window coordinates-x option AddTask function 114AREXX port 262-264 purpose 74 commands 103-104 pointer to account for pushed arguments. code out of loops. The optloop option is the default. For more section code _func: cmpi.b #'+',d0; should I add? fadd.l d1,fp0; add 'mrright' to 'middle' bra.b exitpoint ; ready to return various reductions in strength performs associative reordering of additive operations involving constants to reduce the operation count. 319 Using Assembly Language with C Language Chapter 12 Optimizing Your Code . pull-down menus 20 22splat utility 291 See also specific menustb utility 294 list of pull-down menus and command-line REG assembler directive 307 very busy expression hoisting 333error messages 239 global symbol information 8 examples 238 239 global symbol tables list optlon 237 238 See gst utility options supported 237 238 completing execution before running other commands 30H examples 44, l56 157 executing until breakpoint 30, 32 -h option last command of cmd list parameter 51asm command 324-325 eliminates recalculation of values that have been computed parameters that are currently in registers D7 and D6 and stores the MOVE.LD7,D0 #include MEXIT assembler modules that are compatible with C programs compiled with You can force program counter-relative addressing of data in the code section by specifying an rtype of 0 and an rsize of 2. The assembler will search for the files in the order in which you specify name specifies the name of the control section. You can use the name will be promoted to an int.318 Chapter 11 may be restored when your function terminates. Scratch registers are exitpoint: fmove.l fp0,d0 ; return 'int' in d0 end activating autoswap mode 29examples 141 starting the debugger 25-34 alternate targets 283 284 Optimizer Optiolls window 266 patterns, searching for functiolls 314 321 smake utility 289 calling C functions from assemblerback-tick character (`) z option 244activate command 111 asynchronous tasks 108 noadd: cmpi.b #'-',d0; should I subtract? cannot be reused even in those sections where the variable is not Listing/Cross Reference Options window K 266 follows: See also wdisable command running CodeProbe 10-11 The Peephole Optimizer running cross debugger 96-100DEBUG tool 11 instructions, but the peephole optimizer can help catch the few places where this is not possible. starting the kernel (CPRK) 98 list of options 74 forcing program counter-relativewhen to use 76-77 . . p[temp + j] += 1; IF expression 81 omd utility 249 default value is 4.311 Using Assembly Language with C Language } nosub: reordering of operations to reduce value lifetimes Memory |of size n | it points to the 4-byte return address. 68020 are optional. speed memory is not available on the machine. For example, the equivalent to using the DC directive n times. -m option, tb utility 295 commands for controlling tasks 107, 336-337specifying 135 assemb]es the following statemeIIts to the next ELSE or ENDIF if in the registers required by the assembler module, so no stack manipulation inside the assembler module is necessary. information, see "moving invariants out of loops," earlier in this adding to slink automatically 8, 9return codes 103 break command 49, 135 array-slice parameter 119-120 program execution, controllingenclosing literals in assembler statement See also debugging programsexpressions 303 continuing execution 30 controlling debugging session 27-34-wsource 81 trace option 51, 52-53, 135 retrieving parameters from the stack when option 49, 135317 caution against placing in libraries 110calling C functions from assembler XDEF label[,label] . . . u option 295unload option, gst utility 238 directives allow you to name each control section. The assembler uses The code generator contains all of the knowledge about the target hardware. For example, the following command causes all segments to be loaded into chip-addressable memory, regard0ess of the system gotoline option, scmsg Project menu 258263 displaying value and type of variables 32 alias 89-92DS assembler directive 305 customizing 89-94 dump command 61-66, 145 147 wclear 34addresses, dumping 62 lists gadget 267 -(An) add.w -(a1),d0 d16(An)add.w 10(a1),d0 d8(An,Xn) add.w 10(a1,a2.l),d0 bd(An,Xn) add.w $10000(a1,a2.l),d0 (68020 only) ([bd,An],Xn,od)add.w ([10,a1],a2.l,20),d0(68020 only) these named control sections to control the location of data and code during linking. Chapter 12, "How Does the Compiler Work?," in SAS/C sets the title string that is printed in the page headers in the listing c code segment d data segment By default, the assembler loads the segments into memory not XREF xdata . (period) definibon 69 80 assembles if the expression is less than or equal to 0. VAR2 DC.L $8000 specifying immediate data 314debug=symbolflush option 74 should immediately move the data to the appropriate place. go command 40, 42, 156 arrays syntax errors 43-44Help window 14 The following table shows examples of program counter-relative addressing modes: creating 33See also specific windows clearing 34 windowing interface 12-16 example 34 functions of CodeProbe windows 14-16 function 70opening windows 15 marked by exclamation mark (!) 33 screen layout 12-13 gotofile option, scmsg Project menu 257hide command, SC_SCMSG AREXX port utility 269autoedit option 255 results variable, AREXX 103 Build menu 259 return codes available to AREXX macroscommand options 255-256 22A4-relative address (BSS section) tells the assembler to produce a listing file. keyword. For example, the following assembler module, func, adds or -p Option 220 dzero command 148 -q Option 220displaying ASCII text string 66 syntax and description 219-221 examples 31, 148 -w Option 220syntax 148 See also wenable command specifying with -screen command-line See also wlist commandoption 80 defines a program section. name is a character string, and type must be CODE, DATA, or BSS. The section "Defining Control Sections, In mixed mode, the debugger displays both assembly language The Stack after the| | go command 40, 42-44, 156363 Index setting and showing within CodeProbe See grep utility if (expression See also wclear commandinvoking CodeProbe 11 nosub: fmove.b #-1,fpO; return -1 for error Mode Example ([bd,An,Xn],od)add.w ([10,a1,a2.l],20),d0(68020 only) is defined as that constant. If the variable is used only in { compiler). The default value is 0 (code). subtracts an integer argument and a double argument depending on whether a plus ( + ) sign or a minus (--) sign is passed in the the expression supplied as its argument is not 0. IF statements may be nested. IFC string, string assembles if the strings are identical.306 Chapter 11 reduction5 in strengtll 333 specifying patterns 225-227 reordering of operations 333 -v option 225 runnirlg 333_337 -V option 225 returning values to calling function special symbol in smake utility 277 examples 254task option 107, 110-111, 167 optinlocal option, global optimizer 335running 334 -k option, smake utility 290LLEN assembler directive 306 stepping into called functions 29 rangelen option, opt command 87, 167 stepping over code 29-30ranges trace commands 45-46 caution when using variables for setting compilerrunning 96 following code, the computation of the address ~ p 1 i ] can be exclamation mark (!) dumping 64-65 setting on structures or arrays 71windows displayed in scopts utility oml utility options 253 inserting before undefine command 191 scmsg utility options 255-256263 not find any lines that occur exactly once in each file to seed the algorithm.343 -m3 option 326oml utility 251, 253 alias command 89-92, 128-129 displaying 31, 59-61 entire function, even subtle dead stores are eliminated. rtype specifies whether the code or data in the section are addressed 44-47-x option 290 -noprofile command-line option 79-80 assembler statement expressions nosource option, cover utility 217 303-304 NULL modem cable for cross debugging 96 OPSYN assembler directive 307 autoswap option 88, 165 IFND symbol StackPtr field 109 -u option State field 109asm command 326 section code When a loop is not executed at all, the moved code is executed in code registers D0, D1, A0, A1, FP0, and FP1. want to pass in a register, precede the parameter with the register keyword, two underscores (__), and the register into which you want The prototype for the previous example is the following: In the changed code, i*m can be calculated when m is less than or is placed into register fp0, and the mrright argument is placed into moved after the call: processor and its instructions and makes full use of the 680x0 instruction set. The code generator tries not to generate extra when to use debug= options76-77 compared with alias command 92, 93 debugging programs 25 34, 35 72compared with C preprocessor #define BNE LABEL eliminates unused auto variables and reassigns storage offsets. Often x = i + j; else See also quit command The effect of the matching algorithm is to match blocks of text to each other in the two files. Index debug=symbolflush option 76 sample program 1 37-38 specifying in assembler statements TST. LD2 unions are not re-entrant, although they are serially reusable. Such a You can access data declared in a C function from an assembler The following list describes the steps your assembler module should later in this chapter, discusses the SECTION macro. See underscore (_) and link test with the following commands: > (greater than sign) ---------------------------------------------------------------------------- For example, you may have two files with the following contents: aaa bbb -o option 291 Note: All fields of the operands on the addressing modes marked The following table shows examples of register-direct addressing An addq.w #1 ,a1 The following table shows examples of register-indirect addressing objects, determining type or configuration list option 86, 166 invoking the debugger See slink return command 174Edit menu 260 setting 32, 47-48catch option, opt command 89, 166 tasks command 109 110, 185transformation rules for macros, smake using for cross debugging 97@ command 253 -s option script files To use 32-bit addressing, remove references to the register A4 and to Anesting aliases 92 positional parameters 90 addressable by custom hardware, if it is available. This action . proceed commands 46-47functions 14 temporary, set by go command 40, 43 change block, diff utility 221 character argument. For example, you can write the following program to call the f unc SECTION assembler directive309-310 alternate targets 283 284 valid types and sizes of relocationadding to sc command 9 See also multitasking programs, capability 93 syntax of opt source command 83 setting watches or watch breaks 71 optimizer inspects all references to the variable throughout the register __d1 int mrright); register d1. equates an address or data register with label. location parameter 156smake utility 290 assembler module in your C source file. For each parameter that you int __asm func(register __d0 char lefty, register __fp0 double middle, The remainder of your C program is the same as that shown earlier relocatable expressions 304 commands for running sample See also redirecting output (>)hunks setting ranges 71 266-267 slow execution while using 33, 72wlist command 69, 71, 200 MACRO assembler directive 306 109 113 macrosdeactivate command 111 IFLT expression assembles if the expression is less than 0. The following assembler code is the same f unc module that is described previously in the section "Passing Parameters on the Stack," bne.b nosub ; no, exit with error 320 Chapter 11 CSECT statement, you can use a standard reference to a four byte external address. XREF statement for the external function must appear after the CSECT312 Chapter 11 fmove.d 8(a7),fp0 ; middle menu accelerator keys 23-24-device 97 opening windows 15-16 -line 79 func Module Is High| mrright | Called Memory | | <-- A7+12+n code marking watch breaks 33 hexadecimal notation in assembler . defines an internal label as an external entry. By using the XREF directive, you can then refer to the symbols generated by these Function return values are passed back in one or more registers,321 Using Assembly Language with C Language 1. place the appropriate arguments in the correct registers. rtypersizeDescription See also debugging programsdetermining editing modes 17 any value from 60 to 132. The default value is 132 characters. example, the following code moves data around: -m4 display command 57-61, 143-144 -e option, smake utility 289 CSECT name[, type][, align][, rtype][, rsize] -v option 295user environment 6 Before retrieving arguments from the stack into non-scratch registers, you must first save the contents of those registers, so they -------------------------------------------------------------------------------- NOPAGE label MACRO . ENDM | middle | Return key for executing proceed format of messages 256-257 320 321 badchar option, opt command 87, 165 SECTION directive 309-310 definition 36, 48 See slash (/) See period (.) modes: wbreak command 70-72, 193defining symbols in data section 309 wdisable command 195 ;If you do not, your machine will crash when you run _func: fsub.l 16(a7),fp0 ; subtract 'mrright' turning off 32 character classes, grep utility 226 for (i = O; i < j; i++) { executing until variable changes value R 33 34 executing up to breakpoints 32 r command, oml utility 252 writing assembly language functionssyntax 131 300 314 bdisable command 48, 132 assembly mode benable command 48, 133 depending on the data type declared for the calling function. The CSECT name,type,align,rtype,rsize xxx xxx negation character in grep search 226,statement expressions 303 xxx xxx -a option, smake utility 289 referencing aliases commands with [] include a prototype of your assembler module in your C source < (less than sign) You must begin the definition with a MACRO directive on a line by For example, you could define a macro called acopy as follows: pull-down menus 20-22 -nok 98 for (i = 0; i < n; ++i) 12 Optimizing Your Code If you save the assembler module func in a file named testa.a, you can assemble test.a with the following command: * The smallest item that can be pushed onto the stack is the size of an integer. | lefty | temp = i / 3; running the debugger on optimized code-$ option 225 336 337gst utility 237 239 asm [>listfile] [options] filename . one or more of the following: > prornpt for command line 16H_DEBUG hunks 7, 8 grep utility 224 236 H_SYMBOL hunks 8 See ampersand operator (&) & (ampersand symbol) See ampersand symbol (&) exitpoint: fmove.l fp0,d0 ; return 'int' in d0 rts global optimizer uses worst-case aliasing. Using this option can significantly reduce the amount of optimization that can be performed. The nooptalias option is the default. optcomplexity relative to register A4 or to the PC. The default value is 0. assembles if the expression is greater than 0. O case option 85, 165 module. smake utility 290register parameter 122-123 definition 39call frame 6 with an underscore (_). Do not use this option if you entered all used. Therefore, global optimization changes a register's assigned program has been tested and most errors have been corrected.335 Optimizing Your Code -unit 97examples 99 81symbol tables, global Instead of passing parameters into and out of a function, you can use watches 26, 69 oml utility 253 global optimizer compiler options portname option, scmsg Project menu 258 IFD symbol fsub.l dl,fp0; subtract 'mrright' from 'mlddle' 264 tb utility 295 display command 57command-line editing 17-18 examples 143-144echo option, opt command 84, 166 264 default macros 279-280 retrieve the parameters from the stack. The arguments are placed on IFNE assembler directive 306less than sign (<) addressing 311debug=line option 74 end See CPRK local input files, smake utility 284-286 kernel load module 324 354 Index command 29hidden option 255 REXX languageProject menu 257-259 See AREXX interface quit option 255 optinlocal for (j = 0; j < m; ++j) In addition to specifying addresses relative to address registers and } static by default 70 wmsg command 201 See also wbreak command Workbench screen conventions are as follows: See also benable command asm command 324 See also blist commanddiff utility 219 steps, n refers to the size of your work area in bytes. The test instruction is not needed because the condition codes for the Address field 109 utility 280 281 Optimizer program. [] retrieve any parameters that are passed on the stack before using void f(double d) { branch instruction are set by the move instruction. recognize, contact the Technical Support Division at SAS Institute Inc. Development User's Guide, Volume I, describes the sections produced See badchar option, opt command-m4 option, asm command 326 memcmp function 204 file attempting to match lines in the same way (except that you look at L-1 and L1-1 when finding a matched line L). procedure 96 99 dead store elimination 330 02PC-relative address (code section) index = 23; 230FORMAT assembler directive 305 execute command 152 format parameter EXITM assembler directive 305, 307 fregister command 155 expand command 153 function keys expression parameter actions performed 22-23 operators not accepted 120function line parameter, location expressionsparameter 41 absolute 304 function parameter, location parameter 41, port 264 syntax and description 255-257 rexxonly option, scmsg utility 256scopts utility 266-270 activating autoswap mode 29using with cpr command 10 adding or stripping debugging label 300 location parameter 40 42, 123-124Memory window 15 x lists the expansion text for macros. to the program counter, you also can specify absolute addresses or lefty = '+'; middle = 12345.; mrright = 99; specifying with CSECT directive 311-314 command output 103-104 specifying with SECTION directiveinvoking macros 102-103 function actually may be constants.333 Optimizing Your Code can be changed to short 16 D0.Wlow word of D0 variable during the evaluation of the expression to ensure that the most heavily used variables are always in machine registers. enter immediate data. The following tables summarize the addressing modes supported by the SAS/C Assembler and provide examples of a[i]= p->q.r[10]; definition 107 TTL assembler directive 308 displaying tasks, example 109Type field, tasks command 109 image parameter, location parameter 42See resident libraries, debugging initializing CodeProbe libraries.cpr AREXX macro 106 See cprinit fileline boundary 6 Input window 15 line command, SC_SCMSG AREXX port Build menu, scmsg utility 259 262 built-in functions 202-203-cli command-line option 11, 79 go command 26, 30, 32, 39-44-r option y = temp * 2; long 32 D0.Lall of D0 pointer32 D0.Lall of D0 float 32 D0.Lall of D0 turns off the warnings generated by the -mO option. Use this option syntax 291T -s option 291 stack, assembly language programs 317 -t option format 309 -c option 289 setting and showing options 82-89 70-72 creating watches 33specifying with -w command-line option Running the Optimizers To run the optimizers, specify the appropriate compiler option: See also define command setting watches or watch breaks 71 See also expand commandarrdim option, opt command 86 87, 165 compared with define command 92,93 ASCII option, dump command 65-66 { . starting the cross debugger (CPRX)debug= options 74-76 y = i / 3 + 4; (xxx).Ladd.l (100).l,d0 badchar option 87, 165 Options menu 20 2146 47 See dollar parameter ($) (xxx).Wadd.w (100).w,d0 debugging defining symbols to nothing 93 can be changed to x = temp; } The func assembler module returns an integer.316 Chapter 11 auto variable elimination and those with the __inline keyword. The optinline option is the default when optimize is used. Refer to Chapter 11, "Using Amiga Specific Features of the SAS/C Language," in the SAS/C move.w 4(sp),d0 move.l 6(sp),a5309 Using Assembly Language with C Language Defining Control Sections 33-34devices option, opt command 88, 166 quitting the debugger 34 open by default 12, 26 The assembler supports the following options: The following table shows examples of absolute addressing modes: all option 110, 112 trap handling 113 114 the prefixes. If you specify a directory name as a prefix, include the nesting 52 case option, opt command 85, 165 data1DC.W 10 echo mode 84 setting breakpoints 32 } bra.b exitpoint executing until variable changes valuecommand parameter, help command 27 defines section type and alignment requirements. The section -x option 295utilities __MERGED for near data. You can use a specific name only them. go command 26 See also specific commands invoking the debugger 26address parameter 118 119 -L option 219pointers, dumping 63-64 options supported 219-220variables, dumping 61-62, 75 module using the XREF statement, as follows: the stack from right to left; that is, the leftmost argument is division by 0, but not including iloating-point operations. The global operands in the section "Writing Assembler Statements," earlier in this The following table shows how to specify immediate data: comparing files options 98 See diH utilityrequired on target machine 96 See sc command starting before CPRX 97, 98 Compiler Options Index window 266 CPRX sample program (lines.c) 25starting 98-99 condition control register (CCR) flags 110stripping debug information with -x constants-symfile option 98 subrange parameter 123-124 -cli option 11 syntax 16invoking the debugger 26 See greater than sign (>) counter. For example, the following code calls the function cfunc scratch registers 318sample programs See also debug= options statement expressions 303 illustrations 26 strlen option, opt command 86, 167 309-310 libraries.cpr 106 addsym option macros provided by CodeProbe 101-102 type parameter 124 syntax 9, 75 fmove.b #-1,fp0 ; return -1 for error If your program contains the statement include abc . i, the Referencing Global Data global data.323 Using Assembly Language with C Language information 7 operand 300360 Index This appendix describes the file-matching algorithm used by the diff float (68881) 32 FP0. S single precision in FP0 double (FFP) 32 D0.Lall of D0 MOVE.LD6,D0 assembler searches for the file in the current directory. If that fails, it searches for myinc/abc . i and then yourinc/abc . i. functlons pass parameters on the stack. p[i * m + j] += 1; a significant time saving for loops that are executed many times, as displaying alias definitions 90asm command 323-326 displaying current aliases 89-90 -c option 324 escape characters 19 -d option 324 by the compiler. To use the __asm keyword, you must modify the prototype of the RORG, OFFSET, SECTION, or END directive. OPSYN oldname newname proceed commands 29, 46-47tb utility 295 function key actions 22-23 -i command-line option 79 function keys for command-line editing See dollar sign ($) (asterisk) See asterisk (*) | | <-- A7+8+n optsize following command loads all three sections into high-speed r~AM int func(char lefty, double middle, int mrright); int mrright; zooming to full size 30303 } temp = i + j; x = temp; 1. Enter the SUBI instruction if you need local storage: optimizing 332, 333terminating 99-100 MOVE.LD7,-(A7);push argument Assembler modules may be called from C functions in three ways: . register-direct addressing modes 313 using 75-76 informatioll 311displaying full debugging information 25 98 99determining which option to use 76-77 target machine 96debug=full option 74 [] Identify those lines that occur only once in each file. Assume that these lines match one another. You can access data declared in an assembler module from a C function by placing the data declarations inside a data section and 329 Introduction 334 The Peephole Optimizer 334 Running the Optimizers 335 Global Optimization Compiler Options 336 Global Optimization and the Debugger Mode Example 82-89 proceed command 46-47, 168 induction variable transformations 331specifying 230-231 reductions in strength 333 -x option 99 disables optimizations that might sacrifice code size to save time. Only some loop optimizations do this. The nooptsize option is [label] SECTION name[,type] examples 192 -wregister command-line option 81 syntax and description 70, 192-wsource command-line option 81 d16(PC)add.w 10(PC),d0 assembles if the symbol is defined. IFEQ expression assembles if the expression is 0. form as the compiler. Because the global optimizer works on intermediate code, it has no knowledge of the target processor or its instructions. peephole optimizer abort command, SC_SCMSG AREXX portback-tick character (`) 92 See plus sign ( +) using with detach command 111 112 specifying 228-230 Calling C Functions from Assembler Functions d8(PC,Xn) add.w 10(PC,a2.l), d0 printf("func(+) = %d\n", func(lefty, middle, mrright)); quit command 10-noprofile 79-80 double (68881)96 FP0.Xall of FP0 optimizing subexpressions 331 42 To call an assembler module from your C program, include the 3. after control returns from the called function, adjust the stack context option, opt command 85, 166 cross-debugging 6 a static work area (not on the stack) to hold the returned object and compared with register command 77 echo command 149 expresslon parameter 57Edit menu, scmsg utility 260 can be changed to temp = p->q.r[10]; for (i = 0; i < j; i++) asm -m2 testa.a If you save the C source code in a file named test, you can compile code that is both slower and larger than most optimized code. 0,1,2432-bit absolute address continuing execution 30delfile command, SC_SCMSG AREXX controlling program execution 27-34, port 263 39-53 delnum command, SC_SCMSG AREXX definition 307 -b option 289 temp option, break command 52-53, 135 See specific utilities terminating programs and tasks crashes caused by improper use 26parameters=register option 319 reductions in strength 333functions calling assembler functions from C oml utility 253 ps command 169 diff utility 219 slink lib:c.o test.o testa.o lib lib:sc.lib Note: This approach implies that functions returning structures or 2. push any remaining arguments onto the stack. 3. add an ~ to the front of the function name, and call the function using the JSR instruction. #data add.1 #100,d0 Option Effect The filename is the name of the assembly language source file that else source line fields, assembly language strcpy function 210 setting breakpoints 32, 47-53radix option, opt command 86, 167 single stepping 29, 44-47 range parameter 121 122 using watch and watch break commandswatches 71 } asm -hcdb prog . a -iprefix relocatable 304 See built-in functions reordering 333 -f optionremapping 332 grep utility 225 common subexpression merging 331 Istat utility 244constant propagation and folding 332 rflag command 175 entering options on command line 269 right-Amiga key 23 exiting without saving changes 269 RORG assembler directive307gadgets 267-268 run environment 6 restoring previously saved options 269 build command, SC_SCMSG AREXX portclass command, SC _ SCMSG AREXX port Various arithmetic operations involving constants are reduced in strength. func(lefty,middle,mrright); tasks performed by 269-270 Ikeys catch option 89, 166 -o option context option 85, 166 diff utility 219displaying current task 89 Introduction Your SAS/C Development System provides the following two optimizers: analyzes the assembler instructions and replaces inefficient func(+) = 12444317 Using Assembly Language with C Language (continued)string parameter 123 Debug field 109 ts command 45, 187 examples 185type parameter 124 Optimizing your code may change this correspondence. Also, the command line: Conditional and logical expressions whose results are unused are converted into corresponding if code. For instance, putchar JSR @cfunc ;call function MOVE.LD0,ret ;save return value Global Optimization Compiler Options smake utility 289control flow transformations 333 The Global Optimizer & (and operator) addressesampersand symbol (&) absolute addressing modes 313special symbol in smake utility 277 specifying start-up window coordinatessymbol= option, gst utility 238 sourceis option 77-78See gst utility SPC assembler directive 307 See hypergst utility splat utility 291-293debugging resident libraries 106 -d option 291 definition 107 description 291examples 184 noopttime option is the default. acopy MACRO IFGE expression After setting up the return value, the assembler module exits by addsym 8, 9, 74PLEN assembler directive 307 size sumxes, specifying 301 302examples 131 Nl LL modem cable 96 deactivate command 107, 111, 140 See and operator (&) uses of leftvar have this definition as the single reaching bd(PC,Xn) add.w $10000(PC,a2.l)(68020 only) format parameter 57 AREXX for invoking editors 261-262 multiple arguments 58examples 264-265 windows for setting options 266-267 specifying addresses 309-310comments in smakefiles 274 once in a given asm file. section, 1 indicates a data section, and 2 indicates an See also resident libraries, debuggingdisplaying macro definitions 93 breakpoints 47-53 delcomp command, SC_SCMSG AREXX segment listscreating and using default files 288 assigning pointers 113 creating smakefiles 274-276 semicolon (;) defining transformation rules 280-281 escaping with backslash (\) in echo-e option 289 command 149-f option 289 2. Save registers D2 through D7, A2 through A6 if they will be changed during execution of the module. if 68040 instructions are allowed. -oprefix | | <-- A7+4+n tool types, adding 78 -V option, grep utility 225 top command, SC _ SCMSG AREXX portvariable parameter 125 using in cmd list parameters 50-h option 290 CODE. ([bd,PC],Xn,od)add.w ([10,PC],a2.l,20),d0 (680Z0 only) ([bd,PC,Xn],od)add.w ([10,PC,a2.l],20),d0 (68020 only) See also specific functions cmd_list parameter, break command 50, reversing the steps described earlier: move.w4(sp),\1 move.l6(sp),\2 ENDM MOVE.L d1,xdata(A4)310 Chapter 11 afunc JSR cfunc(PC) 33-34 commands from stdio.h is implemented with a conditional expression. If the result (the original character or an error indication) is not used, GO converts it into if else code, eliminating a load into a register. 1. restore registers that were saved. specifies a prefix that you want placed in front of the output Any drive or directory prefixes in the input filename are discarded data2DC.L 20 . ps command 47blist command 36, 48, 134 -F option, diff utility 219copy propagation 332352 Index The global optimizer optimizes the flow of control and data through an entire function. The global optimizer performs several types of See exclamation mark (!) [] compiling your program with the parameters=register option. This option tells the compiler to pass parameters in registers, but it optimizations: -watch command line option 81 -wwatch command-line option 81 memcpy function 205 memmove function 206 Memory menu 22355 Index type specifies the type of section. The type can be BSS, DATA, or Specifying Addresses with the SECTION Directive lstat utility options 244Indicating comments m smakefiles 274 smake utility 289-290See also ps command Communicating between Assembly syntax and description 185smake utihty 290 allows the compiler to determine which registers to use. blocks and then unmatches the smaller of the blocks. This process is an attempt to satisfy the notion that the differences reported should be 262, 262-264syntax 89, 128 addressing modes supported by SAS/C and operator (&) forcing program counter-relativeAREXX interface 101 addressing 311invoking editors 261-262 trace command 45port 262 2. advance the stack pointer in register A7 past the work area. 3. return to the caller using an RTS instruction. location parameter 120 121dir= option 217 | | |Top of Stack | See braces ({}) See quotes, single ('') \ (backslash character) " (quotes) See backslash character (\) See quotes, double ("") / (slash) & (ampersand operator) induction variable transformations To use the parameters inside your assembler module, you must The arguments mrright, middle, and lefty use 4 bytes, 8 bytes, and 4 bytes, respectively.* Register A7 is the stack pointer, and Note: If you specify the shortintegers option, integers will be operation 300 display command 58 The calling function removes the arguments from the stack.322 Chapter 11 Workbench support 10-11-symfile 98 CodeProbe sample session 25-34 -unit 97 register assignment analyzes the function to determine which auto variables, formal assembler 312not used with register variables 58 dumping 62 append block, diff utility 221 examples 91, 128-129 -d symbol(=value) option 324 expanding alias names 90, 91-h option 324-325344 Index expanding alias names 90fake targets 281-283 preceding with escape character 93 file dependencies, example 275 Anan address register (a0 a7) source modes 83-84strings, dumping 65 66 assembly mode 45, 46, 47, 83 strings gadget 267 C mode 83stripdebug option 77 global optimizer (continued) -f option 225 dead code elimination 331-n option 225 serial ports-i option 290 definition 27strlen function 211 to registers at each point in the function. The optimizer assigns up to three address registers, four data registers, and, if a math mixed mode 46, 83-84, 336structures See back-tick character (') # (pound sign) See pound sign (#) requirements 7 -pipe 97 running 9-11 display command 57 61port 263 next command, SC_SCMSG AREXX port.ONEERROR fake target 282 263 online help nodebug option 74 See help command . return; performs various transformations to eliminate unreachable code or useless control structures. For example, the following code calls the function cfunc with two parameters that are currently in registers D7 and D6 and stores the XREF cfunc If your C function is declared using the __asm keyword, you should pass the parameters in the appropriate registers. sections. You must use either the SECTION or CSECT directive before you define any code or data. A SECTION or CSECT directive defines IFGT assembler directive 306 tb utility 295 ! (exclamation mark) $ (dollar sign) ^ (caret) 2 bytes instead of 4. Prototype Generation Options window 267redirecting output (>) take to save register values and establish frame pointers. In these hiding in double quotes 92symload command 112-113 default macros 279-280task handling by CodeProbe 108 defining transformation rules 280-281tasks command 109-110 oml utility 253 -s option 253 smake utility 290syntax and description 250-251 syntax 323 statement expressions 303 u option 326auto variable elimination and remapping IFND assembler directive 306left-Amiga m keyboard shortcut 29, 34 dead store elimination 330-331number of times characters may appear, asterisk ( ) braces ({}) data, examiningdebug=full option 76 stack variables 110 oml utility 253 register variables. Generally speaking, the variables that are most used at a given moving invariants out of loops 331options supported 225 optimizeturns on both the global and peephole optimizers. wenable command 196 bda 32-bit byte displacemer1t .IGNORE fake target 282diff utility 220 control sections See also CPRK See CSECT assembler directiveSee also CPRX cross-development mode (continued)data structures, displaying preparing to use cross debugger 96dead code elimination 331 reasolls for cross-debugging 95-96Debug field, tasks command 109 terminating CPRX and CPRK 99-100using 76 CSECT assembler directive 310-314when to use 76 77 parameters 310 using 75 program counter-relative addressing debug=symbol option 74 modes, examples 314generating H DEBUG hunks 8 SUBI n,A7 source option, opt command 83 84, 166subrange parameter 119, lZ3 124 Source window symbol 7 functions 15See also debug=symbol option open by default 12, 26symbol command 183 examples 291-293syntax and description 112-113, 184 -startup command-line option 26, 80 fake targets 281-283 State field, tasks command 109 multiple targets 283 Name field, tasks command 109 -t option 253 state of the machine target machine 7, 96 Name field 109 tb utility 294-296 tb utility 295 assembly mode 47grep utility 224 equivalents 20-22register command 66-68, 171 q optionexamples 171 [] using the __asm keyword and specifying which registers parameters are placed in. 3. Save floating-point registers FP2 through FP7 if a 68881 math insert editing mode 17 263 defines the end of conditional assembly. This directive turns off optimizeturns on only the global optimizer. conditional 49 50 functions 322 asm command (continued)used in array-slice parameter 119 -i option 325wild card indicator 34 syntax and description 244 multiple targets, smake utility 283 IFLE expression diffutility 220syntax 66 67, 171 grep utility 225 register-direct addressing modes 313 quiet option, break command 52-53, 135Register window 15, 81 SC_SCMSG AREXX port 263displaying contents 67 To use all the capabilities of the debugger, the lines in the source code opt source mixed337 Optimizing Your Code -m0 option 325 asynchronous tasks 108 . XDEFafunc MOVE.W data1(A4),D0 MOVE.L data2(A4),D1 See percent sign (%) coprocessor is present and will be used by the module. The steps you take to call a C function from an assembler program menu accelerator keys 23-24example 217-218 number parameter 121 merge option 217 1. push the arguments on the stack in the correct order. multiple listing lines for each source line. running on optimized code 336 337 -screen 80 terminology 5_7-speed 97 breakpoints, setting 32-w 80 clearing watches and watch breaks 34-wb. 11, 80 compiling and linking 25-wd0alog 81 Development System User's Guide, Volume I, for information about rsize specifies the size of the offset for the address. If you specify an specify an rsize of 2, the assembler uses the value of rtype to determine how to address code or data in the section. The The following table summarizes the valid types and sizes of 12A4-relative address (data section) -cx pull-down menus 20-22 nosource option 217 2. call the function using the JSR instruction. the beginning of a relocatable control section. Pararneters on these relative to the PC: CodeProbe tasks 108V CPRK and CPRX 99 oml utility 251 -v option scmsg utility 255 grep utility 225 text command, SC SCMSG AREXX portoml utility 253 trace command 45 46, 186, 187assembler statement expressions302 radix option 86 steps for debugging 8 rangelen option 87trace commands 45-46 search path 87 88watch and wbreak commands32-34, source file location 77 78watches and watch breaks 69-72 optcomplexity option 335 patterns at beginning or end of line, syntax and description 170 effect of opt task command 110 defines the complexity of functions considered small by associated with array indexing).332 Chapter 12 In many cases, optimized code is more difflcult to debug than non- diff utility options 219 220 grep search pattern 226, 231 grep utllity options 225 ANSI # and ## operators not supported before the new prefix is added. Do not include blanks in the prefix. Passing parameters in registers produces a faster, smaller executable module.315 Using Assembly Language with C Language defining the data with an XDEF statement. The following code defines two variables in assembly language and shows how to declare them in -m2 option 325 at sign ((?) -m4 option 326replacing underscore in function names -o option 326 for compiler 318 If you include >listfile, the assembler sends the source listing and See braces ({}) debugging environment, setting up 73-94 cllrrellt task, displaying 89alias command 89 92 oml utility252changing default environment short form of display command 30with -cli and wb options 11 -d Option choosing command-line options 78-81 asm command 324 context option 85 point are assigned to registers. For example, variables occurring in330 Chapter12 addresses, specifying with CSECT a C function. specifies that the sections designated by x are to be loaded into In Assembly Language In C Language CSECT data extern long VAR1; loops are more likely to be assigned to registers. The global optimizer attempts to keep a variable assigned to a register for as The global optimizer overrides the register keyword in the declarations of integer, double, and pointer variables. Because of the listing file. NOOBJ Using the SECTION Directive The SECTION directive follows this format: online help 26-27 array-slice parameter 119 quitting the debugger 34command-line editing 16-19 restart command 26command-line equivalents for menu items address parameter 40memory, dumping Language and C Language XDEF VAR1,VAR2,VAR3 extern long VAR2; VAR1 DC.L $4000 In C Language In Assembly Language compared with proceed command 44, displaying value and type 32 directive 311 314B assembler directives 304-308 assembler statements, writing 300-304-b option __asm keyword 319-320 diff utility 219 fullctions 322 non-expansion of escaped macro whatis command 68-69, 197 Z _ (underscore) optdepth option 335 specifying 231 control flow transformations 333cross-development mode 95-100 CTRL-C, terminating CPRK and CPRX 99using 76 syntax and description 68, 197 when option break command 49, 135 optimized code. You may want to use the optimizer only after the main the portability of the C language, it is difficult for a programmer to name= option, gst utility 238 terminating 251 optrdepth option 336 redirecting output 224 long VAR1=0x4000; XREF VAR1,VAR2 long VAR1=0x4000; . definition and rightvar will not change before each use. This optimization supports other optimizations. ignorepath option, opt command 85, 166oml utility 251 57-72 precautions 111-112 image 6 libraries integers, dumping 65link library 250 data actual data you want loaded into the register Dna data register (d0--d7) uninitialized data section (like the udata section used by the b bss or uninitialized data The following list describes each of the parameters. Ctrl-L key 23when to use 76-77 interlace mode link option 9, 25 Specifying Addresses with the CSECT Directive (back-tick character) See -i command-line option linker grep search pattern 225, 226, 230-231 defining aliases 90 avoids bus contention between the processor and the custom Ctrl-W key 23 debugger clearing watches and watch breaks 34port 262 "Defining Control Sections," later in this chapter, discusses the brackets ([])C enclosing characters in grep search 226, 228-230 C functions, calling See calling assembler functions from branch instructionsC functions after option 49, 135 grep utility 225 See also opt commandPeriod (.) know the number of available registers provided by the target asm -ccdb prog.a CSECT macro. The compiler accepts the following options to modify the operation of -d register command 66-68scrolling 31350 Index Dialog window (continued) special symbol in smake utility 277 specifying start-up window coordinatesspecifying hexadecimal numbers in 81 assembler statement expressions options supported 244 Modules window 15 terminating CPRX 100 modifying 110358 Index once in a given asm file. the Program Counter (PC). activates the debugging mode. compiler uses the more advanced registration allocation algorithms cmd0ist parameter 50, 135 smake utility 289 quiet option 52 53, 135 calling an assembler module 316 optdepth specifies a prefix that should be placed in front of filenames in trailing slash (/). For example, you can assemble the file named testprog. a with the following command: asm -imyinc/ -iyourinc/ testprog.a -l[x][m][i] code- or data-generated information beside the source line. The x, m, and i produce the following slightly different listings: i lists the source for text from INCLUDE files as well as the resident libraries, debugging 105-106lines.c 25 RemTask function 114 programs 36 definition 5, 32, 47Calls window l4 multitasking programs 108 grep search pattern 226 catch command 107, 112, 139 preventing debugger from stoppin 51 Catch New Devices option syntax 48-49, 135parameters=register option 318-319 318 -buffer command-line option 78 79 characters and strings, dumping 65 66 262clear command SC SCMSG AREXX port original source file. -m0 displaying arrays and structures 30-32 -wwatch 81 purpose 202 Code Generation Options window 266 specifies that only 68000 instructions are allowed. This option [label] DC[.size] expression[,expression] . . . tb utility 295compared with trace command 44, range is 0 to 6, and the default value is 3. label MACRO begins a macro definition. The following section, "Defining and symload command 106 adding addsym option to slink curly bracesSee CodeProbe smake utility 289current task 89 346 Index CodeProbe 3-24command-line editing 16-19 basic features 4editing function keys 17-18 See also scopts utility grep wildcard character 225, 228, 230 exits the macro expansion. This directive is a synonym for EXITM. Using the CSECT Directive The CSECT directive follows this format: defines a constant value in memory. ENDC issues warning messages if, for example, you use instructions that are only available on the 68020. This option is the default. changes and enhancements 5 escape characters in commands 19 -pipe command-line option 97 cover utility options 217 plus sign (+) See cpr commandLinker Options window 267 linking programs 9, 25 LIST assembler directive 306 The name and type parameters describe the control section being information in the section. The align parameter is ignored. The -s [label] DS[.size] n reserves (defines) n memory locations of the size indicated by .size. ELSE NARG includes the section name at the beginning of each hunk. -u specifies that you want the assembler to prefix external references external names with leading underscores. You should specify this option when you assemble startup code. displaying variable values and types 32command output for AREXX macros executing breakpoints 32103-104 source mode, setting 27-2820-22 command line 16-19 escape sequences in character compiling and linking programs 9 strings18 19 definition 26, 36typical usage 9 following list describes each of the parameters: begins an alternative for the IF directive. [label] END defines the end of the program. in SAS/C software. Even though the compiler does not have each of the IFxx directives. ENDM ends a macro definition. label EQU expression assigns permanently the value of expression to label. dynamic information about program execution that would indicate optinline cpr command 9-10 using backslash (\) 18 splat utility 291customizing Dialog window commands label EQUR register EXITM IFNC string,string nesting structure to make a reasonable approximation. align specifies the alignment requirements of the control section as a dead store elimination default options, displaying 82 continuing execution 30-wregister 81 assembles if the strings are not identical. assembles if the symbol is not defined. IFNE expression assembles if the expression is not equal to 0. INCLUDE "filename" starting the debugger 25-26 customizing Dialog window commands stepping over code 29-30 89-94 range parameter 121-122options supported 217 register parameter 122-123running 216 SC_SCMSG AREXX port 262-264syntax and description 216 217 shortcuts for command names 16 cpr command 9-10 stops the production of the object file. OFFSET n defines a synonym for opcodes. PAGE eliminates the assignment of a value to a variable if the value is not /* code that does not refer to index */ -t option 244 multitasking programs, debugging 107-114 See also AREXX macrosdesign considerations 113-114 NOFORMAT assembler directive 306OpenDevice function 114 NOLIST assembler directive 307 operand field, assembly language source non-floating-point instructionsline 300 assembler statement size suffixes 301 operation field, assembly language NOOB) assembler directive 307source line 300 NOPAGE assembler directive 307 operators oml utility 253 echo option 84, 166 -b option 253source option 46, 77, 83, 84, 166, 336 speclal parameterS 118-125 available command-line options 10 By specifying parameters in the CSECT directive, you can generate the data=near (base-relative data) and code=near (program includes external files into the source. You can nest INCLUDE counter-relative addressing) compiler options. You can force address register-relative addressing of data in the BSS section by specifying an rtype of 2 and an rsize of 2. Any XREF J list command 161 162 list option . index = 12; 331 Optimizing Your Code splat utility 291assigned to Return key 29 eliminates definitions of the form leftvar = rightvar when all variable parameter 125 -wb option 11 statements for external data elements must appear after the CSECT statement, and all data must be addressed relative to register A4. For >prompt 16 .cpr extension for macros 102 communications parametersinitializing CodeProbe 81-82 defining for cross debugging 97 suppresSing execution with -noprofile -device 97 option 79 80 -pipe 97 CPRK 324debug= options 74-76 See dump command debug=fullflush option 76349 Index debug=symbol option 75-76running CodeProbe 9-11 define command 92-93 sample program 2 53-56 . ignorepath option 85 single stepping 44-47 initializing CodeProbe 81-82starting the debugger 25-26 source modes 83 84whatis command 68-69 programs 36delete command, SC_SCMSG AREXX port compiling and linking programs 9, 25 263 displaying arrays and structures 30-32dependent file, smake utility 273 dump command 61-66definition 107 examining data and data structuresexamples 142 executing breakpoints 32 syntax 111, 142 Dialog window commands-$ option, grep utility 225 diff utility 219-223 characters and strings, dumping 65-66 append block 221 compared with register command 77 . . -c option 219decimal option 65 change block 221 examples 147 delete block 220 float option 64 error messageS 222-223 floating-point numbers, dumping 64-65 profile scripts quit option, scmsg utility 255 jump command 89, 160 gst utility 237 opt command 86, 166 definition 40, 120See dump command -F option 219integers, dumping 65 forms 40memset function 207 function line parameter 41 menu accelerator keys 23-24, 29, 34 function parameter 41, 42, 121 menus integer parameter 121 Message window 15 line parameter 41See also wmsg command module parameter 42, 120MEXIT assembler directive306 syntax 120 minus sign (-) CSECT TEXT,0 MOVE.Ldata2(A4),D1 MOVE.Ld1,xdata(A4) log command 163-164special symbol in smake utility 229, 277 Note: If the XREF statement for the external data precedes the statement. and the function must be called relative to the program CSECT TEXT,0,,0,2 XREFcfunc d8an 8 bit displacement