Z80 Routines:Math:Division - Revision history

Zeda: Added an optimized 32/16

2019-09-30T23:18:24Z

Added an optimized 32/16

2017-03-15T12:11:46Z

Undo revision 11386 by Jacobly (talk)

2017-03-15T11:09:20Z

I'm just going to assume Rounded 16/8 was also broken.

2017-03-15T11:05:10Z

Fixed 24/8 and 32/8.

2017-03-15T10:56:15Z

16/8 was broken

2012-07-10T23:14:20Z

Added 32/16 division

2012-01-09T17:00:45Z

‎Rounded 16/8 division

2012-01-09T17:00:00Z

Added the rounded 16/8 routine. Feel free to modify for other version. Just double the remainder and compare to the divisor.

2010-05-14T09:07:13Z

correct some typos

2009-11-05T16:49:57Z

added categorization

@@ Line 154: / Line 154: @@
 	djnz	Div32By16_Loop
 	ret
   </nowiki>

@@ Line 41: / Line 41: @@
     add	hl, hl
     rla
     cp	c
     jr	c, $+4
     sub	c
     inc	l
@@ Line 87: / Line 89: @@
     rl	e
     rla
     cp	d
     jr	c, $+4
     sub	d
     inc	l
@@ Line 111: / Line 115: @@
     rl	d
     rla
     cp	c
     jr	c, $+4
     sub	c
     inc	l
@@ Line 119: / Line 125: @@
     ret
   </nowiki>

@@ Line 41: / Line 41: @@
     add	hl, hl
     rla
     cp	c
     jr	c, $+4
     sub	c
     inc	l
@@ Line 89: / Line 87: @@
     rl	e
     rla
     cp	d
     jr	c, $+4
     sub	d
     inc	l
@@ Line 115: / Line 111: @@
     rl	d
     rla
     cp	c
     jr	c, $+4
     sub	c
     inc	l
@@ Line 125: / Line 119: @@
     ret
   </nowiki>
@@ Line 168: / Line 133: @@
     add	hl, hl
     rla
     cp	c
     jr	c, $+4

@@ Line 44: / Line 44: @@
     cp	c
     jr	c, $+4
     sub	c
     inc	l
@@ Line 88: / Line 89: @@
     rl	e
     rla
     cp	d
     jr	c, $+4
     sub	d
     inc	l
@@ Line 112: / Line 115: @@
     rl	d
     rla
     cp	c
     jr	c, $+4
     sub	c
     inc	l

@@ Line 41: / Line 41: @@
     add	hl, hl
     rla
     cp	c
     jr	c, $+4

← Older revision		Revision as of 23:14, 10 July 2012
Line 119:		Line 119:

	ret		ret
		+	</nowiki>
		+	== 32/16 division ==
		+
		+	The following routine divides acix by de and places the quotient in acix and the remainder in hl
		+
		+	<nowiki>
		+	Div32By16:
		+	; IN: ACIX=dividend, DE=divisor
		+	; OUT: ACIX=quotient, DE=divisor, HL=remainder, B=0
		+	ld hl,0
		+	ld b,32
		+	Div32By16_Loop:
		+	add ix,ix
		+	rl c
		+	rla
		+	adc hl,hl
		+	jr c,Div32By16_Overflow
		+	sbc hl,de
		+	jr nc,Div32By16_SetBit
		+	add hl,de
		+	djnz Div32By16_Loop
		+	ret
		+	Div32By16_Overflow:
		+	or a
		+	sbc hl,de
		+	Div32By16_SetBit:
		+	.db $DD,$2C ; inc ixl, change to inc ix to avoid undocumented
		+	djnz Div32By16_Loop
		+	ret
	</nowiki>		</nowiki>

@@ Line 138: / Line 138: @@
     inc	l
     djnz	_loop
-;THis part is the rounding
+;This part is the rounding
     add a,a
     cp	c

@@ Line 4: / Line 4: @@
 == Introduction ==
-All these routines use the restoring divison algorithm, adapted to the z80 architecture to maximize speed.
+All these routines use the restoring division algorithm, adapted to the z80 architecture to maximize speed.
 They can easily be unrolled to gain some speed.
 == 8/8 division ==
-The following routine multiplies d by e and places the quotient in d and the remainder in a
+The following routine divides d by e and places the quotient in d and the remainder in a
   <nowiki>
@@ Line 31: / Line 31: @@
 == 16/8 division ==
-The following routine multiplies hl by c and places the quotient in hl and the remainder in a
+The following routine divides hl by c and places the quotient in hl and the remainder in a
   <nowiki>

← Older revision		Revision as of 16:49, 5 November 2009
Line 1:		Line 1:
		+	[[Category:Z80 Routines:Math\|Division]]
		+	[[Category:Z80 Routines\|Division]]
		+
	== Introduction ==		== Introduction ==