* -------------------------------------------------------------------- * Example CH12-1.s * -------------------------------------------------------------------- ; some system include files... include exec/types.i include exec/libraries.i include exec/exec_lib.i include dos/dos_lib.i * -------------------------------------------------------------------- CALLSYS MACRO LINKLIB _LVO\1,\2 ENDM ; CALLSYS macro is used to extend LINKLIB and thus avoid the explicit ; use of the _LVO prefixes in the function names... * -------------------------------------------------------------------- WRITEDOS MACRO movem.l d1-d3,-(sp) preserve registers d1-d3 move.l \2,d1 DOS output file handle move.l #\1,d2 start of message move.l #\1_SIZEOF,d3 size of message CALLSYS Write,_DOSBase DOS call to write message movem.l (sp)+,d1-d3 restore registers d1-d3 ENDM ; WRITEDOS is used to Write() DOS text messages and control character ; streams. The macro expects the user to supply a text label followed ; by a valid DOS output handle. ; Usage: WRITEDOS , ; Example: WRITEDOS message, _stdout ; Within the program each message X must have a corresponding size EQUate, ; X_SIZEOF, containing the size of the message. An easy way to set this up ; is to define the size label immediately after defining the message itself ; and use the assembler's location counter to do the length calculation, ; like this... ; message dc.b 'test text',0 ; message_SIZEOF EQU *-message * -------------------------------------------------------------------- ; EQUate definitions... _AbsExecBase EQU 4 LF EQU 10 NULL EQU 0 * -------------------------------------------------------------------- ; main program code... move.l _AbsExecBase,_SysBase set up SysBase variable lea dos_name,a1 library name start in a1 moveq #0,d0 any version will do CALLSYS OpenLibrary,_SysBase macro (see text for details) move.l d0,_DOSBase store returned value beq EXIT test result for success ; if we reach here then the DOS library is open and its functions can ; be safely used! CALLSYS Output,_DOSBase get default output handle move.l d0,_stdout store output handle beq CLOSELIB ; have obtained valid output handle so message can be written... WRITEDOS message, _stdout get DOS to write message ; all done so now we can close DOS library... CLOSELIB move.l _DOSBase,a1 base needed in a1 CALLSYS CloseLibrary, _SysBase ; and terminate the program via an rts instruction... EXIT clr.l d0 rts logical end of program * -------------------------------------------------------------------- ; variables and static data... _stdout ds.l 1 _SysBase ds.l 1 _DOSBase ds.l 1 dos_name dc.b 'dos.library',0 message dc.b 'this is just my line of test text',LF message_SIZEOF EQU *-message * --------------------------------------------------------------------