WebSVN – NedoOS – Blame – /src/gp/common/muldiv.asm

Rev	Author	Line No.	Line
1870	galstaff	1	;dehl = m
		2	;dehl' = n
		3	;out: dehl = m/n
		4	uintdiv32
		5	ld a,h
		6	cpl
		7	ld h,a
		8	ld a,l
		9	cpl
		10	ld l,a
		11	ld (.dividendlo),hl
		12	ld a,d
		13	cpl
		14	ld h,a
		15	ld a,e
		16	cpl
		17	ld l,a
		18	ld (.dividendhi),hl
		19	ld a,1
		20	ld bc,0
		21	ld de,1
		22	ld hl,0
		23	ld iy,0
		24	ld (.templo),hl
		25	ld (.temphi),hl
		26	exx
		27	ld bc,de
		28	ex de,hl
		29	bit 7,b
		30	jr nz,.rshiftloop
		31	.lshiftloop
		32	sla de
		33	rl bc
		34	exx
		35	sla de
		36	rl bc
		37	exx
		38	inc a
		39	bit 7,b
		40	jr z,.lshiftloop
		41	.rshiftloop
		42	.templo=$+2
		43	ld ix,0
		44	.temphi=$+1
		45	ld hl,0
		46	add ix,de
		47	adc hl,bc
		48	jr c,.nextbit
		49	push ix
		50	push hl
		51	push de
		52	.dividendlo=$+1
		53	ld de,0
		54	add ix,de
		55	.dividendhi=$+1
		56	ld de,0
		57	adc hl,de
		58	pop de
		59	pop hl
		60	pop ix
		61	jr c,.nextbit
		62	ld (.templo),ix
		63	ld (.temphi),hl
		64	exx
		65	add iy,de
		66	add hl,bc
		67	exx
		68	.nextbit
		69	srl bc
		70	rr de
		71	exx
		72	srl bc
		73	rr de
		74	exx
		75	dec a
		76	jr nz,.rshiftloop
		77	exx
		78	ld de,iy
		79	ex de,hl
		80	ret
		81
		82	;bc = m
		83	;de = n
		84	;out: dehl = m*n
		85	uintmul16
1945	galstaff	86	ld a,c
		87	ld c,b
1870	galstaff	88	ld hl,0
1945	galstaff	89	ld b,16
		90	.loop add hl,hl
		91	rla
		92	rl c
1870	galstaff	93	jr nc,.skip
		94	add hl,de
1945	galstaff	95	adc a,0
		96	jr nc,.skip
		97	inc c
		98	.skip djnz .loop
		99	ld d,c
		100	ld e,a
1870	galstaff	101	ret

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