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view lib/alib/jsr_cmd.as @ 3295:6b7a7b233925 default tip
makefile: Allow PORTS with level1/2 mix
https://sourceforge.net/p/nitros9/feature-requests/10/
author | Tormod Volden <debian.tormod@gmail.com> |
---|---|
date | Tue, 19 Apr 2022 18:12:17 +0200 |
parents | 03f26e88b809 |
children |
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*************************************** * Subroutine to jsr to subroutine from 1 character command table * OTHER MODULES NEEDED: none * ENTRY: A=1 char command * X=start of jump table * EXIT: CC carry set if entry not found * all other regs can be modified by subs * Note format of table: each entry is three bytes * 0-match character (command) * 1..2-offset to routine * It is the user's job to set commands to proper case for matching... * end of table=NULL * sample table: fcc /A/ * fdb routineA-* * fcc /B/ * fdb routineB-* * fcb 0 nam Jsr to 1 char Command ttl Assembler Library Module section .text JSR_CMD: tst ,x end of table? beq jsrerr cmpa ,x+ found match? beq docmd yes, go do it leax 2,x next entry bra JSR_CMD * no match found, return with carry set jsrerr coma set error flag rts * command found, do call and return docmd ldd ,x get offset to routine jsr d,x andcc #%11111110 clear carry rts endsect