* -------------------------------------------------------------------- * Example CH12-2.s * -------------------------------------------------------------------- ; some system include files... include exec/types.i include exec/libraries.i include libraries/dos.i include exec/exec_lib.i * -------------------------------------------------------------------- ; a macro to extend LINKLIB and thus avoid the explicit use ; of the _LVO prefixes in the function names... CALLSYS MACRO LINKLIB _LVO\1,\2 ENDM * -------------------------------------------------------------------- ; This macro expects the user to supply a string pointer name followed ; by a valid DOS output handle. 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 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 * -------------------------------------------------------------------- ; EQUate definitions... _AbsExecBase EQU 4 _LVOWrite EQU -48 _LVOOutput EQU -60 LF EQU 10 * -------------------------------------------------------------------- ; 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 ; 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 a valid output handle so messages can be written... WRITEDOS message1, _stdout write messages WRITEDOS message2, _stdout WRITEDOS message3, _stdout WRITEDOS message4, _stdout ; 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... 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 DOSNAME message1 dc.b 'Once you have seen how easy it is to write',LF message1_SIZEOF EQU *-message1 message2 dc.b 'one line of text using the WRITEDOS macro...',LF message2_SIZEOF EQU *-message2 message3 dc.b 'you should be able to write any number of',LF message3_SIZEOF EQU *-message3 message4 dc.b 'similar programs yourself!',LF message4_SIZEOF EQU *-message4 * --------------------------------------------------------------------