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

← 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

Fgbrain at 11:07, 16 January 2016

2016-01-16T11:07:53Z

← 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]]

Fgbrain: /* Firmware */

2016-01-16T10:46:25Z

Firmware

← Older revision		Revision as of 10:46, 16 January 2016
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	call SCR_PREV_LINE		call SCR_PREV_LINE


			ACTUAL #BC29 ROUTINE FOLLOWS:

			ld a,h:sub #08:ld h,a:and #38:cp #38:ret nz
			ld a,h:add #40:ld h,a:ld a,l:sub reg1*2:ld l,a:ret nc ; reg1= CRTC reg.1 value
			ld a,h:dec h:and #07:ret nz
			ld a,h:add #08:ld h,a:ret

	</pre>		</pre>

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

Fgbrain: /* Firmware */

2016-01-16T10:43:58Z

Firmware

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

Prodatron: /* Without Firmware */

2015-04-17T09:47:38Z

Without Firmware

← Older revision		Revision as of 09:47, 17 April 2015
Line 23:		Line 23:
	'''Output:''' HL=Address of the next line		'''Output:''' HL=Address of the next line

	'''Destroyed:''' AF		'''Destroyed:''' AF,BC

	<pre>		<pre>
Line 34:		Line 34:
	add h		add h
	ld h,a		ld h,a
	~~and 64~~		ret nc
	ret nz		ld bc,#c050
	ld bc,~~16304~~		add hl,bc
	~~sbc~~ hl,bc
	ret		ret
	</pre>		</pre>

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]]