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cc65/libsrc/common/cc65_idiv32by16r16.s

40 lines
755 B
ArmAsm

;
; Ullrich von Bassewitz, 2009-11-04
;
; CC65 library: 32by16 => 16 signed division
;
.export _cc65_idiv32by16r16
.import idiv32by16r16, incsp4
.include "zeropage.inc"
;---------------------------------------------------------------------------
; 32by16 division.
.proc _cc65_idiv32by16r16
pha ; Save rhs
; Copy from stack to zeropage. This assumes ptr1 and ptr2 are adjacent.
ldy #3
@L1: lda (sp),y
sta ptr1,y
dey
bpl @L1
lda #4
clc
adc sp
sta sp
bcc @L2
inc sp+1
@L2: pla ; Old rhs
jmp idiv32by16r16
.endproc