Programming:Integer Division - Revision history

Litwr: /* Fast 32bit division */ a bit faster

2015-12-26T13:27:00Z

Fast 32bit division: a bit faster

← Older revision		Revision as of 13:27, 26 December 2015
Line 183:		Line 183:
	'''Not used:''' IX, IY		'''Not used:''' IX, IY

	'''CPC Cycles:''' ~~1080~~-~~2572~~ (~~1826~~ on average), ~~270~~-~~643~~ usec (~~456~~ on average)		'''CPC Cycles:''' 1016-2444 (1730 on average), 254-611 usec (432 on average)

	'''Size:''' ~~261~~ bytes		'''Size:''' 277 bytes

	<pre>		<pre>
	div_r macro		div_r macro
	local t2		local t2
	~~EX DE, HL~~		SLA E
	~~ADD~~ ~~HL, HL~~		RL D
	EX ~~DE, HL~~
	ADC HL, HL		ADC HL, HL

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	div_e macro		div_e macro
	local t1,t2		local t1,t2
	~~EX DE, HL~~		SLA E
	~~ADD~~ ~~HL, HL~~		RL D
	EX ~~DE, HL~~
	ADC HL, HL		ADC HL, HL
	JR C, t1		JR C, t1

2015-11-16T16:51:46Z

32bit division

← Older revision		Revision as of 16:51, 16 November 2015
Line 114:		Line 114:

	'''Destroyed:''' AF,DE,IY		'''Destroyed:''' AF,DE,IY

			'''CPC Cycles:''' approximately 7800, 1900 usec

			'''Size:''' 91 bytes

	<pre>		<pre>
Line 168:		Line 172:
	ret ;IY,BC=Value1 DIV Value2		ret ;IY,BC=Value1 DIV Value2
	</pre>		</pre>


	== Fast 32bit division ==		== Fast 32bit division ==

2015-11-16T16:47:21Z

Fast 32bit division

← Older revision		Revision as of 16:47, 16 November 2015
Line 181:		Line 181:

	'''CPC Cycles:''' 1080-2572 (1826 on average), 270-643 usec (456 on average)		'''CPC Cycles:''' 1080-2572 (1826 on average), 270-643 usec (456 on average)

			'''Size:''' 261 bytes

	<pre>		<pre>
Line 218:		Line 220:
	t2		t2
	endm		endm
	div32x16 proc ; BCDE = HLDE/BC, HL = HLDE%BC		div32x16 proc ; BCDE = HLDE/BC, HL = HLDE%BC
	local DIV16, DIV32R, ~~DIV32F~~		local DIV16, DIV32R, DIV32E
	DEC BC		DEC BC
	LD A, B		LD A, B
Line 239:		Line 241:
	EX (SP), HL		EX (SP), HL
	EX DE, HL		EX DE, HL
	CALL ~~DIV32F~~		CALL DIV32E
	POP BC		POP BC
	RET		RET
	DIV16		DIV16
	CALL ~~DIV32F~~		CALL DIV32E
	LD BC, 0000		LD BC, 0000
	RET		RET
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	endm		endm
	RET		RET
	~~endp~~
	DIV32E ; DE = HLDE/(-BC), HL = HLDE%(-BC)		DIV32E ; DE = HLDE/(-BC), HL = HLDE%(-BC)
	CALL $+3		CALL $+3

2015-11-16T16:31:19Z

Fast 32bit division: correction and additional information is added

← Older revision		Revision as of 16:31, 16 November 2015
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	'''Not used:''' IX, IY		'''Not used:''' IX, IY

			'''CPC Cycles:''' 1080-2572 (1826 on average), 270-643 usec (456 on average)

	<pre>		<pre>
	~~div~~ macro		div_r macro
	local ~~t1,~~t2		local t2
	~~ADD HL, HL~~
	EX DE, HL		EX DE, HL
	ADD HL, HL		ADD HL, HL
	EX DE, HL		EX DE, HL
	~~JP NC~~, t1		ADC HL, HL

	~~INC HL~~
	t1
	LD A, L		LD A, L
	ADD A, C		ADD A, C
	LD A, H		LD A, H
	ADC A, B		ADC A, B
	JP NC, t2		JR NC, t2

	ADD HL, BC		ADD HL, BC
	INC DE		INC DE
	t2		t2
	endm		endm
			div_e macro
			local t1,t2
			EX DE, HL
			ADD HL, HL
			EX DE, HL
			ADC HL, HL
			JR C, t1

			LD A, L
			ADD A, C
			LD A, H
			ADC A, B
			JR NC, t2
			t1
			ADD HL, BC
			INC DE
			t2
			endm
	div32x16 proc ; BCDE = HLDE/BC, HL = HLDE%BC		div32x16 proc ; BCDE = HLDE/BC, HL = HLDE%BC
	local t1, ~~DIV32_~~, ~~DIV320~~		local DIV16, DIV32R, DIV32F
	DEC BC		DEC BC
	LD A, B		LD A, B
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	LD A, B		LD A, B
	ADC A, H		ADC A, H
	JP NC, ~~DIV32_~~		JR NC, DIV16

	PUSH DE		PUSH DE
	EX DE, HL		EX DE, HL
	LD HL, 0000		LD HL, 0000
	CALL ~~DIV320~~		CALL DIV32R
	EX DE, HL		EX DE, HL
	EX (SP), HL		EX (SP), HL
	EX DE, HL		EX DE, HL
	CALL ~~DIV320~~		CALL DIV32F
	POP BC		POP BC
	RET		RET
	~~DIV32_~~		DIV16
	CALL ~~DIV320~~		CALL DIV32F
	LD BC, 0000		LD BC, 0000
	RET		RET
	~~DIV320~~ ; DE = HLDE/(-BC), HL = HLDE%(-BC)		DIV32R ; DE = HLDE/(-BC), HL = HLDE%(-BC), -BC < $8000
	CALL t1		CALL $+3
	t1
	rept 8		rept 8
	~~div~~		div_r
			endm
			RET
			endp
			DIV32E ; DE = HLDE/(-BC), HL = HLDE%(-BC)
			CALL $+3
			rept 8
			div_e
	endm		endm
	RET		RET
	endp		endp
	</pre>		</pre>

	== Web links ==		== Web links ==

2015-11-14T15:23:54Z

the new fast division added

← Older revision		Revision as of 15:23, 14 November 2015
Line 169:		Line 169:
	</pre>		</pre>


			== Fast 32bit division ==

			'''Input:''' HL,DE=Value1, BC=Value2

			'''Output:''' BCDE=Value1/Value2, HL=Value1 MOD Value2

			'''Destroyed:''' AF

			'''Not used:''' IX, IY

			<pre>
			div macro
			local t1,t2
			ADD HL, HL
			EX DE, HL
			ADD HL, HL
			EX DE, HL
			JP NC, t1

			INC HL
			t1
			LD A, L
			ADD A, C
			LD A, H
			ADC A, B
			JP NC, t2

			ADD HL, BC
			INC DE
			t2
			endm

			div32x16 proc ; BCDE = HLDE/BC, HL = HLDE%BC
			local t1, DIV32_, DIV320
			DEC BC
			LD A, B
			CPL
			LD B, A
			LD A, C
			CPL
			LD C, A
			ADD A, L
			LD A, B
			ADC A, H
			JP NC, DIV32_

			PUSH DE
			EX DE, HL
			LD HL, 0000
			CALL DIV320
			EX DE, HL
			EX (SP), HL
			EX DE, HL
			CALL DIV320
			POP BC
			RET
			DIV32_
			CALL DIV320
			LD BC, 0000
			RET
			DIV320 ; DE = HLDE/(-BC), HL = HLDE%(-BC)
			CALL t1
			t1
			rept 8
			div
			endm
			RET
			endp
			</pre>
	== Web links ==		== Web links ==

2011-12-19T19:39:59Z

Web links: added link to division routines for the Sega Master System

← Older revision		Revision as of 19:39, 19 December 2011
Line 171:		Line 171:
	== Web links ==		== Web links ==

			* [http://www.smspower.org/Development/DivMod Division implementation for the Sega Master System]
	* [http://map.tni.nl/articles/mult_div_shifts.php Multiplications and divisions on the MSX Assembly Page]		* [http://map.tni.nl/articles/mult_div_shifts.php Multiplications and divisions on the MSX Assembly Page]

	[[Category:Programming]]		[[Category:Programming]]

2007-05-05T11:48:57Z

added weblink

← Older revision		Revision as of 11:48, 5 May 2007
Line 1:		Line 1:

	== 8bit division ==		== 8bit division ==

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	ret ;IY,BC=Value1 DIV Value2		ret ;IY,BC=Value1 DIV Value2
	</pre>		</pre>

			== Web links ==

			* [http://map.tni.nl/articles/mult_div_shifts.php Multiplications and divisions on the MSX Assembly Page]

	[[Category:Programming]]		[[Category:Programming]]

2006-09-21T14:20:50Z

Added 8bit division

← Older revision		Revision as of 14:20, 21 September 2006
Line 1:		Line 1:

			== 8bit division ==

			'''Input:''' HL=Value1, C=Value2

			'''Output:''' L=Value1/Value2, H=Value1 MOD Value2

			'''Destroyed:''' AF,BC

			<pre>
			LD B,8
			Div_Next:
			ADD HL,HL
			LD A,H
			SUB C
			JR C,Div_NXTB
			LD H,A
			INC L
			Div_NXTB:
			DJNZ Div_Next
			RET
			</pre>

	== 16bit division ==		== 16bit division ==

2006-09-16T08:25:49Z

16bit division

2006-08-13T14:08:05Z