Programming:Integer Division - Revision history

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

2015-12-26T13:27:00Z

‎Fast 32bit division: a bit faster

2015-11-16T16:51:46Z

‎32bit division

2015-11-16T16:47:21Z

‎Fast 32bit division

2015-11-16T16:31:19Z

‎Fast 32bit division: correction and additional information is added

2015-11-14T15:23:54Z

the new fast division added

2011-12-19T19:39:59Z

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

2007-05-05T11:48:57Z

added weblink

2006-09-21T14:20:50Z

Added 8bit division

2006-09-16T08:25:49Z

‎16bit division

2006-08-13T14:08:05Z

@@ Line 183: / Line 183: @@
 '''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>
 div_r macro
       local t2
-      EX    DE, HL
+      SLA   E
-     ADD   HL, HL
+      RL    D
-      EX    DE, HL
       ADC   HL, HL
@@ Line 207: / Line 206: @@
 div_e macro
       local t1,t2
-      EX    DE, HL
+      SLA   E
-     ADD   HL, HL
+      RL    D
-      EX    DE, HL
       ADC   HL, HL
       JR    C, t1

@@ Line 114: / Line 114: @@
 '''Destroyed:''' AF,DE,IY
 <pre>
@@ Line 168: / Line 172: @@
          ret             ;IY,BC=Value1 DIV Value2
 </pre>
 == Fast 32bit division ==

@@ Line 181: / Line 181: @@
 '''CPC Cycles:''' 1080-2572 (1826 on average), 270-643 usec (456 on average)
 <pre>
@@ Line 218: / Line 220: @@
 t2
       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
       LD    A, B
@@ Line 239: / Line 241: @@
       EX    (SP), HL
       EX    DE, HL
-      CALL  DIV32F
+      CALL  DIV32E
       POP   BC
       RET
 DIV16
-      CALL  DIV32F
+      CALL  DIV32E
       LD    BC, 0000
       RET
@@ Line 252: / Line 254: @@
       endm
       RET
 DIV32E   ; DE = HLDE/(-BC), HL = HLDE%(-BC)
       CALL  $+3

@@ Line 179: / Line 179: @@
 '''Not used:''' IX, IY
 <pre>
- div macro
+div_r macro
-      local t1,t2
+      local t2
-     ADD   HL, HL
       EX    DE, HL
       ADD   HL, HL
       EX    DE, HL
-      JP    NC, t1
+      ADC   HL, HL
       LD    A, L
       ADD   A, C
       LD    A, H
       ADC   A, B
-      JP    NC, t2
+      JR    NC, t2
       ADD   HL, BC
       INC   DE
- t2
+t2
       endm
   div32x16 proc  ; BCDE = HLDE/BC, HL = HLDE%BC
-      local t1, DIV32_, DIV320
+      local DIV16, DIV32R, DIV32F
       DEC   BC
       LD    A, B
@@ Line 214: / Line 230: @@
       LD    A, B
       ADC   A, H
-      JP    NC, DIV32_
+      JR    NC, DIV16
       PUSH  DE
       EX    DE, HL
       LD    HL, 0000
-      CALL  DIV320
+      CALL  DIV32R
       EX    DE, HL
       EX    (SP), HL
       EX    DE, HL
-      CALL  DIV320
+      CALL  DIV32F
       POP   BC
       RET
- DIV32_
+DIV16
-      CALL  DIV320
+      CALL  DIV32F
       LD    BC, 0000
       RET
- DIV320   ; DE = HLDE/(-BC), HL = HLDE%(-BC)
+DIV32R   ; DE = HLDE/(-BC), HL = HLDE%(-BC), -BC < $8000
-      CALL  t1
+      CALL  $+3
- t1
       rept 8
-      div
+      div_r
       endm
       RET
       endp
 </pre>
 == Web links ==

← 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 ==

@@ Line 171: / Line 171: @@
 == Web links ==
 * [http://map.tni.nl/articles/mult_div_shifts.php Multiplications and divisions on the MSX Assembly Page]
 [[Category:Programming]]

@@ Line 1: / Line 1: @@
 == 8bit division ==
@@ Line 169: / Line 168: @@
          ret             ;IY,BC=Value1 DIV Value2
 </pre>
 [[Category:Programming]]

← 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 ==

@@ Line 16: / Line 16: @@
 clcd161 rl c
          rla
-         rl l
+         adc hl,hl
-        rl h
          sbc hl,de
          jr nc,clcd162