Programming:Fast Square Root - Revision history

Executioner: /* Faster Again */

2007-09-19T01:03:54Z

Faster Again

← Older revision		Revision as of 01:03, 19 September 2007
Line 66:		Line 66:

	<pre>		<pre>
	CP 8 * 8		SqrtA: CP 8 * 8
	JR NC,ge8		JR NC,ge8
	CP 4 * 4		CP 4 * 4
Line 113:		Line 113:
	RET		RET
	</pre>		</pre>

			The average time for this routine, including CALL and RET is 26.9us.

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

Executioner: /* Faster Again */

2007-09-19T00:52:06Z

Faster Again

← Older revision		Revision as of 00:52, 19 September 2007
Line 74:		Line 74:
	OR A		OR A
	RET Z		RET Z
	~~INC~~ A		LD A,1
	RET		RET
	ge2: CP 3 * 3		ge2: CP 3 * 3

Executioner: /* Faster Again */ - Optimised using SBC A:ADD n

2007-09-19T00:46:50Z

Faster Again: - Optimised using SBC A:ADD n

← Older revision		Revision as of 00:46, 19 September 2007
Line 77:		Line 77:
	RET		RET
	ge2: CP 3 * 3		ge2: CP 3 * 3
	LD A~~, 3~~		SBC A
	~~SBC 0~~		ADD 3
	RET		RET
	ge4: CP 6 * 6		ge4: CP 6 * 6
	JR NC,ge6		JR NC,ge6
	CP 5 * 5		CP 5 * 5
	LD A~~, 5~~		SBC A
	~~SBC 0~~		ADD 5
	RET		RET
	ge6: CP 7 * 7		ge6: CP 7 * 7
	LD A~~, 7~~		SBC A
	~~SBC 0~~		ADD 7
	RET		RET
	ge8: CP 12 * 12		ge8: CP 12 * 12
Line 95:		Line 95:
	JR NC,ge10		JR NC,ge10
	CP 9 * 9		CP 9 * 9
	LD A,9		SBC A
	~~SBC 0~~		ADD 9
	RET		RET
	ge10: CP 11 * 11		ge10: CP 11 * 11
	LD A~~,11~~		SBC A
	~~SBC 0~~		ADD 11
	RET		RET
	ge12: CP 14 * 14		ge12: CP 14 * 14
	JR NC,ge14		JR NC,ge14
	CP 13 * 13		CP 13 * 13
	LD A~~,13~~		SBC A
	~~SBC 0~~		ADD 13
	RET		RET
	ge14: CP 15 * 15		ge14: CP 15 * 15
	LD A~~,15~~		SBC A
	~~SBC 0~~		ADD 15
	RET		RET
	</pre>		</pre>
	[[Category:Programming]]		[[Category:Programming]]

Executioner: Added optimised version (much much faster!)

2007-09-19T00:11:56Z

Added optimised version (much much faster!)

@@ Line 58: / Line 58: @@
 done:
 	LD	A,(Bsqr)
 	RET
 </pre>
 [[Category:Programming]]

PulkoMandy: category

2006-08-13T14:07:24Z

Octoate: Initial page

2006-08-04T22:34:01Z

Initial page

New page

'''Input:''' A = ''The number you want to find the square root of''

'''Output:''' A = ''Square root of the number supplied in A''

'''Destroys:''' A,B,DE

'''Call:''' CALL SqrtA

<pre>
;this routine written 10 - 28 - 2003
;ported from the 68k version (by Frank Yaul) by konrad meyer
;this routine is not as memory efficient as it could be; this is
;done to save cycles

;note: this routine is using the fastest available method
;and will come within 1 below the #
;note: this routine is inaccurate in #s below 4

SqrtA:
LD (Asqr),A
SRL A
JR DataOver
Asqr:
.DB 0
Bsqr:
.DB 0
Csqr:
.DB 0
DataOver:
LD (Bsqr),A
LD B,A
LD (Csqr),A
iterate:
LD A,(Asqr)
LD B,(Bsqr)
LD D,A
LD E,B
divideDbyEreturnA:
RL D
RLA
SUB E
JR nc,$+3
ADD A,E
LD E,A
LD A,D
CPL
LD B,(Bsqr)
ADD A,B
SRL A
LD (Bsqr),A
LD A,(Csqr)
DEC A
LD B,(Bsqr)
CP B
JR z,done
LD (Csqr),B
JR iterate
done:
LD A,(Bsqr)
RET
</pre>

← Older revision		Revision as of 14:07, 13 August 2006
Line 60:		Line 60:
	RET		RET
	</pre>		</pre>
			[[Category:Programming]]