Programming:Next / previous line calculation - Revision history

Fgbrain: /* Fastest way to print a character in Mode 2 */

2016-01-16T11:11:34Z

‎Fastest way to print a character in Mode 2

Fgbrain at 11:07, 16 January 2016

2016-01-16T11:07:53Z

Fgbrain: /* Firmware */

2016-01-16T10:46:25Z

‎Firmware

Fgbrain: /* Firmware */

2016-01-16T10:43:58Z

‎Firmware

Prodatron: /* Without Firmware */

2015-04-17T09:47:38Z

‎Without Firmware

Octoate: Created page with "= Next line = This routines calculate the next line from the given address. == Firmware == '''Input:''' HL=Address '''Output:''' HL=Address of the next line '''Destroyed:'''..."

2010-12-28T11:45:33Z

Created page with "= Next line = This routines calculate the next line from the given address. == Firmware == '''Input:''' HL=Address '''Output:''' HL=Address of the next line '''Destroyed:'''..."

New page

= Next line =

This routines calculate the next line from the given address.

== Firmware ==

'''Input:''' HL=Address

'''Output:''' HL=Address of the next line

'''Destroyed:''' AF

<pre>
SCR_NEXT_LINE equ #BC26

call SCR_NEXT_LINE
</pre>

== Without Firmware ==

'''Input:''' HL=Address

'''Output:''' HL=Address of the next line

'''Destroyed:''' AF

<pre>
; Richard Fairhurst
; October 1997
;
;*** Next line down from HL ***

.nline ld a,8
add h
ld h,a
and 64
ret nz
ld bc,16304
sbc hl,bc
ret
</pre>

= Previous line =

This routines calculate the previous line from the given address.

== Firmware ==

'''Input:''' HL=Address

'''Output:''' HL=Address of the previous line

'''Destroyed:''' AF

<pre>
SCR_PREV_LINE equ #BC29

call SCR_PREV_LINE
</pre>

[[Category:Programming]]

← Older revision		Revision as of 11:11, 16 January 2016
Line 82:		Line 82:


−	'''Input:''' HL=Address DE=screen address (works for every first line of screen !! For example: &C000, &C050, &C0A0 etc..)	+	'''Input:''' HL=Address of sprite/char.data DE=screen address (works for every first line of screen !! For example: &C000, &C050, &C0A0 etc..)

	'''Destroyed:''' AF, C		'''Destroyed:''' AF, C

← Older revision		Revision as of 11:07, 16 January 2016
Line 76:		Line 76:

	</pre>		</pre>
		+
		+
		+
		+	= Fastest way to print a character in Mode 2 =
		+
		+
		+	'''Input:''' HL=Address DE=screen address (works for every first line of screen !! For example: &C000, &C050, &C0A0 etc..)
		+
		+	'''Destroyed:''' AF, C
		+
		+	'''Unchanged:''' DE returns to its input value (through C register)
		+
		+	''''If HL is not page aligned, INC HL must be used instead of INC L (1 NOP SLOWER!)
		+
		+
		+	<pre>
		+	ld c,d
		+	ld a,(hl):ld(de),a:inc l:set 3,d
		+	ld a,(hl):ld(de),a:inc l:ld d,c:set 4,d
		+	ld a,(hl):ld(de),a:inc l:set 3,d
		+	ld a,(hl):ld(de),a:inc l:ld d,c:set 5,d
		+	ld a,(hl):ld(de),a:inc l:set 3,d
		+	ld a,(hl):ld(de),a:inc l:set 4,d:res 3,d
		+	ld a,(hl):ld(de),a:inc l:set 3,d
		+	ld a,(hl):ld(de),a
		+	ld d,c
		+
		+	</pre>
		+
		+

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

← Older revision		Revision as of 10:43, 16 January 2016
Line 15:		Line 15:

	call SCR_NEXT_LINE		call SCR_NEXT_LINE
		+
		+
		+	ACTUAL #BC26 ROUTINE FOLLOWS:
		+
		+	ld a,h:add #08:ld h,a:and #38:ret nz
		+	ld a,h:sub #40:ld h,a:ld a,l:add reg1*2:ld l,a:ret nc ;reg1= CRTC reg.1 value
		+	inc h:ld a,h:and #07:ret nz
		+	ld a,h:sub #08:ld h,a:ret
		+
		+
	</pre>		</pre>

@@ Line 23: / Line 23: @@
 '''Output:''' HL=Address of the next line
-'''Destroyed:''' AF
+'''Destroyed:''' AF,BC
 <pre>
@@ Line 34: / Line 34: @@
          add h
          ld h,a
-        and 64
+         ret nc
-         ret nz
+         ld bc,#c050
-         ld bc,16304
+         add hl,bc
-         sbc hl,bc
          ret
 </pre>

@@ Line 66: / Line 66: @@
 call SCR_PREV_LINE
 </pre>
 [[Category:Programming]]