Z80 Routines:Optimized:addAtoHL - Revision history

Galandros: added to math category

2009-11-09T08:42:44Z

added to math category

Galandros at 08:41, 9 November 2009

2009-11-09T08:41:48Z

Fullmetalcoder at 10:55, 8 November 2009

2009-11-08T10:55:23Z

Dr. D'nar: grammar

2009-11-08T00:06:32Z

grammar

Galandros at 14:53, 5 November 2009

2009-11-05T14:53:06Z

Galandros at 14:52, 5 November 2009

2009-11-05T14:52:52Z

Galandros: New page: AddAtoHL AddAtoHL This is an optimized addAtoHL because it is a little faster and doesn't need other 16-bit register. Also it...

2009-11-05T14:51:46Z

New page: AddAtoHL AddAtoHL This is an optimized addAtoHL because it is a little faster and doesn't need other 16-bit register. Also it...

New page

[[Category:Z80 Routines:Optimized|AddAtoHL]]
[[Category:Z80 Routines|AddAtoHL]]

This is an optimized addAtoHL because it is a little faster and doesn't need other 16-bit register.
Also it can be changed to add A to any 16-bit register. The only down is 1 extra byte.

Normal way:
<nowiki>
ld d,$00
ld e,a
add hl,de
;4 bytes and 22 clock cycles
</nowiki>

<nowiki>
addAtoHL:
add a,l
ld l,a
adc a,h ;^ this two line
sub l ;v increase h if there is carry
ld h,a
;5 bytes and 20 clock cycles
;but no other 16-bit register pair messed
</nowiki>

Thanks to CoBB.

← Older revision		Revision as of 08:42, 9 November 2009
Line 1:		Line 1:
	[[Category:Z80 Routines:Optimized\|AddAtoHL]]		[[Category:Z80 Routines:Optimized\|AddAtoHL]]
		+	[[Category:Z80 Routines:Math\|AddAtoHL]]
	[[Category:Z80 Routines\|AddAtoHL]]		[[Category:Z80 Routines\|AddAtoHL]]

← Older revision		Revision as of 10:55, 8 November 2009
Line 28:		Line 28:

	Thanks to CoBB.		Thanks to CoBB.
		+
		+	another alternate way which uses branching and saves 1 T-state on one path (when carrying to h) :
		+	<nowiki>
		+	addAtoHL:
		+	add a,l
		+	ld l,a
		+	jr nc, $+3
		+	inc h
		+	;5 bytes, 19/20 clock cycles
		+	</nowiki>

@@ Line 16: / Line 16: @@
   </nowiki>
   <nowiki>
 addAtoHL:
@@ Line 29: / Line 30: @@
 Thanks to CoBB.
-another alternate way which uses branching and saves 1 T-state on one path (when carrying to h) :
+Another alternate way which uses branching and saves 1 T-state on one path (when carrying to h) :
   <nowiki>
 addAtoHL:

@@ Line 2: / Line 2: @@
 [[Category:Z80 Routines|AddAtoHL]]
-This is an optimized addAtoHL because it is a little faster and doesn't need other 16-bit register.
+This is an optimized addAtoHL. It is a little faster and doesn't need another 16-bit register.
-Also it can be changed to add A to any 16-bit register. The only down is 1 extra byte.
+Also it can be changed to add A to any 16-bit register. The only down side is one extra byte.
-Use it as a subroutine (don't forget the ret) or a macro.
+Use it as a subroutine (don't forget the ret) or macro.
 Normal way:
@@ Line 20: / Line 20: @@
 	add a,l
 	ld l,a
-	adc a,h    ;^ this two line
+	adc a,h    ;^ these two lines
 	sub l      ;v increase h if there is carry
 	ld h,a
 ;5 bytes and 20 clock cycles
-;but no other 16-bit register pair messed
+;but no other 16-bit register messed up
   </nowiki>
 Thanks to CoBB.