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Adapted div & mod for popptr1.

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This commit is contained in:
IrgendwerA8
2018-05-24 03:55:40 +02:00
parent 746e3d1454
commit dd411efd1c
9 changed files with 92 additions and 122 deletions
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45
libsrc/runtime/udiv.s
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@@ -3,9 +3,10 @@
;
; CC65 runtime: division for unsigned ints
;
; Don't use tmp1 here, the signed division tunnels data with it!
.export tosudiva0, tosudivax, udiv16
.import popsreg
.import popptr1
.importzp sreg, ptr1, ptr4
@@ -14,50 +15,50 @@ tosudiva0:
tosudivax:
sta ptr4
stx ptr4+1 ; Save right operand
jsr popsreg ; Get left operand
jsr popptr1 ; Get left operand
; Do the division
jsr udiv16
; Result is in sreg, remainder in ptr1
; Result is in ptr1, remainder in sreg
lda sreg
ldx sreg+1
lda ptr1
ldx ptr1+1
rts
;---------------------------------------------------------------------------
; 16by16 division. Divide sreg by ptr4. Result is in sreg, remainder in ptr1
; 16by16 division. Divide ptr1 by ptr4. Result is in ptr1, remainder in sreg
; (see mult-div.s from "The Fridge").
; This is also the entry point for the signed division
udiv16: lda #0
sta ptr1+1
sta sreg+1
ldy #16
ldx ptr4+1
beq udiv16by8a
L0: asl sreg
rol sreg+1
rol a
L0: asl ptr1
rol ptr1+1
rol a
rol sreg+1
pha
tax
cmp ptr4
lda ptr1+1
lda sreg+1
sbc ptr4+1
bcc L1
sta ptr1+1
pla
sta sreg+1
txa
sbc ptr4
pha
inc sreg
tax
inc ptr1
L1: pla
L1: txa
dey
bne L0
sta ptr1
sta sreg
rts
@@ -65,18 +66,18 @@ L1: pla
; 16by8 division
udiv16by8a:
@L0: asl sreg
rol sreg+1
@L0: asl ptr1
rol ptr1+1
rol a
bcs @L1
cmp ptr4
bcc @L2
@L1: sbc ptr4
inc sreg
inc ptr1
@L2: dey
bne @L0
sta ptr1
sta sreg
rts