62 lines
546 B
ArmAsm
62 lines
546 B
ArmAsm
.define .dvi2
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.sect .text
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.sect .rom
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.sect .data
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.sect .bss
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.sect .text
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! 16-bit signed division
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! parameters:
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! bc: divisor
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! de: dividend
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! de: result (out)
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! no check on overflow
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.dvi2:
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xor a
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ld h,a
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ld l,a
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sbc hl,bc
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jp m,1f
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ld b,h
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ld c,l
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cpl
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1:
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or a
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ld hl,0
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sbc hl,de
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jp m,1f
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ex de,hl
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cpl
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1:
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push af
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ld hl,0
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ld a,16
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0:
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add hl,hl
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ex de,hl
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add hl,hl
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ex de,hl
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jr nc,1f
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inc hl
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or a
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1:
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sbc hl,bc
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inc de
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jp p,2f
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add hl,bc
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dec de
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2:
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dec a
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jr nz,0b
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pop af
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or a
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jr z,1f
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ld hl,0
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sbc hl,de
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ex de,hl
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1:
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ret
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