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New functions to swap register variables

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git-svn-id: svn://svn.cc65.org/cc65/trunk@1629 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cuz 2002-11-25 12:38:38 +00:00
parent da44e7ae4b
commit e1385c925a
4 changed files with 88 additions and 0 deletions
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3
libsrc/runtime/Makefile
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@ -159,6 +159,9 @@ OBJS = add.o \
pushlysp.o \
pushw.o \
pushwsp.o \
regswap.o \
regswap1.o \
regswap2.o \
return0.o \
return1.o \
rsub.o \

28
libsrc/runtime/regswap.s Normal file
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@ -0,0 +1,28 @@
;
; Ullrich von Bassewitz, 25.11.2002
;
; CC65 runtime: Swap x bytes of register variable space
;
.export regswap
.importzp sp, regbank, tmp1
.proc regswap
sta tmp1 ; Store count
@L1: lda regbank,x ; Get old value
pha ; Save it
lda (sp),y ; Get stack loc
sta regbank,x ; Store new value
pla
sta (sp),y ; Store old value
inx
iny
dec tmp1
bne @L1
rts
.endproc

22
libsrc/runtime/regswap1.s Normal file
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@ -0,0 +1,22 @@
;
; Ullrich von Bassewitz, 25.11.2002
;
; CC65 runtime: Swap 1 byte of register variable space
;
.export regswap1
.importzp sp, regbank
.proc regswap1
lda regbank,x ; Get old value
pha ; Save it
lda (sp),y ; Get stack loc
sta regbank,x ; Store new value
pla
sta (sp),y ; Store old value
rts
.endproc

35
libsrc/runtime/regswap2.s Normal file
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@ -0,0 +1,35 @@
;
; Ullrich von Bassewitz, 25.11.2002
;
; CC65 runtime: Swap 2 bytes of register variable space
;
.export regswap2
.importzp sp, regbank
.proc regswap2
; First byte
lda regbank,x ; Get old value
pha ; Save it
lda (sp),y ; Get stack loc
sta regbank,x ; Store new value
pla
sta (sp),y ; Store old value
; Second byte
iny
lda regbank+1,x ; Get old value
pha ; Save it
lda (sp),y ; Get stack loc
sta regbank+1,x ; Store new value
pla
sta (sp),y ; Store old value
rts
.endproc