Initial revision

mach/z80/int/dvi4.s

@@ -0,0 +1,74 @@
+.dvi4:
+	pop hl
+	ld (retaddr),hl
+	xor a
+	ld (.flag1),a
+	ld (.flag2),a
+	ld ix,0
+	add ix,sp
+	ld b,(ix+7)		! dividend
+	bit 7,b
+	jr z,1f
+	ld c,(ix+6)
+	ld d,(ix+5)
+	ld e,(ix+4)
+	call .negbd
+	ld (ix+7),b
+	ld (ix+6),c
+	ld (ix+5),d
+	ld (ix+4),e
+	ld a,1
+	ld (.flag1),a
+1:
+	ld b,(ix+3)
+	bit 7,b
+	jr z,2f
+	call .negst
+	ld a,1
+	ld (.flag2),a
+2:
+	call .dvu4
+	ld a,(.flag1)
+	or a
+	jr z,3f
+	call .negbd
+3:
+	ld (.savebc),bc
+	ld (.savede),de
+	ld a,(.flag2)
+	ld b,a
+	ld a,(.flag1)
+	xor b
+	jr z,4f
+	call .negst
+4:
+	ld bc,(.savebc)
+	ld de,(.savede)
+	ld hl,(retaddr)
+	jp (hl)
+.negbd:
+	xor a
+	ld h,a
+	ld l,a
+	sbc hl,de
+	ex de,hl
+	ld h,a
+	ld l,a
+	sbc hl,bc
+	ld b,h
+	ld c,l
+	ret
+.negst:
+	pop iy
+	pop de
+	pop bc
+	call .negbd
+	push bc
+	push de
+	jp (iy)
+.data
+	.flag1: .byte 0
+	.flag2: .byte 0
+	retaddr:.word 0
+	.savebc: .word 0
+	.savede: .word 0