view lib/alib/jsr_cmd2.as @ 3220:9ccec98c9897

Updated IDE Driver makefile so it will have place holders for dsk, dskclean, and dskcopy so that make does not error out when chaining into the driver tree to build disk images where applicable.
author David Ladd <drencor-xeen@users.sourceforge.net>
date Wed, 20 Dec 2017 16:10:50 -0600
parents 03f26e88b809
children
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***************************************

* Subroutine to jsr to subroutine from 2 character command table

* OTHER MODULES NEEDED: none

* ENTRY: D=2 char command
*        X=start of jump table

* EXIT:  CC carry set if entry not found 
*        all other regs can be modified by subs
*        D and X always modified

* Note format of table: each entry is four bytes
*                       0..1-match characters (command)
*                       2..3-offset to routine

* It is the user's job to set commands to proper case for matching...

* end of table=NULL

* sample table:  fcc /A1/
*                fdb routineA-*
*                fcc /B1/
*                fdb routineB-*
*                fcb 0 


 nam Jsr to 2 char Command
 ttl Assembler Library Module

 section .text

JSR_CMD2:
 tst ,x end of table?
 beq jsrerr

 cmpd ,x++ found match?
 beq docmd yes, go do it

 leax 2,x next entry
 bra JSR_CMD2

* 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