Z80 Routines:Graphic:Fastcopy - Revision history

Galandros at 22:17, 26 October 2009

2009-10-26T22:17:55Z

Galandros: spell check

2009-10-26T14:22:28Z

spell check

Galandros: Routines:Graphic:Fastcopy moved to Z80 Routines:Graphic:Fastcopy: unite z80 routines

2009-10-25T19:49:46Z

Routines:Graphic:Fastcopy moved to Z80 Routines:Graphic:Fastcopy: unite z80 routines

Qarnos: added double-buffer routine

2009-05-31T11:11:59Z

added double-buffer routine

Show changes

Darkstone knight: erase buffer fastcopy is now at the same speed as the regulair one

2008-11-09T11:15:47Z

erase buffer fastcopy is now at the same speed as the regulair one

Darkstone knight: "faster" fastcopy

2008-11-06T16:35:46Z

"faster" fastcopy

Jim e: minor changes

2007-06-15T03:03:41Z

minor changes

TD-Linux: /* Safe Copy */

2006-06-20T16:17:36Z

‎Safe Copy

Jim e: No reason to waste ex af,af'

2005-08-06T23:47:16Z

No reason to waste ex af,af'

AndyJ: /* Safe Copy */ ";It must be noted that you cannot specify any other register. Only f works.'

2005-07-06T19:54:56Z

‎Safe Copy: ";It must be noted that you cannot specify any other register. Only f works.'

@@ Line 1: / Line 1: @@
-[[Category:Z80 Routines:Graphic|fastcopy]][[Category:Z80 Routines|fastcopy]]
+[[Category:Z80 Routines:Graphic|FastCopyToLCD]][[Category:Z80 Routines|FastCopyToLCD]]
 __FORCETOC__
+==IonFastCopy==
-==IonFastcopy==
 '''Warning:''' ''The routines presented below may fail on some calculators due to manufacturing defects. Before using any of the routines below, read the safecopy section below.''
 The '''Fastcopy''' routine is used to copy the content of the Graph Buffer to the screen. It concerns all TI-z80 calculators, except TI-85 and TI-86, that has a special RAM area directly mapped to the screen.
-Fastcopy is widely used, because the rom call _GrBufCpy waits too long between each output to the LCD driver. Using Fastcopy instead of _GrBufCpy increases significantly the speed of a program if it refreshes often the display (such as a lot of games). Most shells have this routine as built-in (ION, MirageOS, Venus ...).
+FastCopy is widely used, because the rom call _GrBufCpy waits too long between each output to the LCD driver. Using Fastcopy instead of _GrBufCpy increases significantly the speed of a program if it refreshes often the display (such as a lot of games). Most shells have this routine as built-in (ION, MirageOS, Venus ...).
 Here is Joe Wingbermuehle's version, which is the one used in ION.
@@ Line 14: / Line 13: @@
 ;-----> Copy the gbuf to the screen (fast)
 ;Input: nothing
-;Output:graph buffer is copied to the screen
+;Output: graph buffer is copied to the screen
 fastCopy:
   di

@@ Line 85: / Line 85: @@
 '''ld (hl),0''' takes 10 cycles, so we can replace both '''inc hl''' (6 cycles) whit '''nop''' (4 cycles) and thus load 12 into de instead of 10.
-this is still 2 clocks slower than the origional routine, so we change '''inc de''' and '''dec de''' (6 cycles) and use '''ret z''' (5 cycles) instand.
+this is still 2 clocks slower than the original routine, so we change '''inc de''' and '''dec de''' (6 cycles) and use '''ret z''' (5 cycles) instead.
 ==Safe Copy==
 Many calculators recently manufactured by TI contained a buggy LCD driver, which had different (or varying) delays required to interface with it. Using the fast copy routines above with the LCDs will cause the LCD to display garbled information. However, we can do some additional hardware work to solve this problem, by waiting until we know the LCD is ready to accept a command:
-* Bit 7 of Port 10 tells us that the lcd can accept an instruction
+* Bit 7 of Port 10 tells us that the LCD can accept an instruction
 * '''SE Only:''' Bit 1 of Port 2 tells us that how long since the last lcd access

@@ Line 68: / Line 68: @@
   out ($10),a
   add hl,de
-  ld de,11
+  ld de,12
 fastCopyLoop:
   add hl,de
-  inc hl
+  nop
-  inc de
+  ret z
   ld a,(hl)
   ld (hl),0    ; clears the graph buffer at the same time
   out ($11),a
-  dec de
+  ret z
   djnz fastCopyLoop
   ld a,c
@@ Line 85: / Line 85: @@
 '''ld (hl),0''' takes 10 cycles, so we can replace both '''inc hl''' (6 cycles) whit '''nop''' (4 cycles) and thus load 12 into de instead of 10.
 ==Safe Copy==

@@ Line 84: / Line 84: @@
 </nowiki>
-'''ld (hl),0''' takes 10 cycles, so we can do with one less '''inc hl''' (6 cycles) and thus load 11 into de instead of 10.
+'''ld (hl),0''' takes 10 cycles, so we can replace both '''inc hl''' (6 cycles) whit '''nop''' (4 cycles) and thus load 12 into de instead of 10.
 ==Safe Copy==

@@ Line 1: / Line 1: @@
 [[Category:Z80 Routines:Graphic|fastcopy]][[Category:Z80 Routines|fastcopy]]
-'''Warning:''' The routines presented below will fail on some calculators due to manufacturing defects. Before using any of the routines below, read the safe copy section below.
+__FORCETOC__
 The '''Fastcopy''' routine is used to copy the content of the Graph Buffer to the screen. It concerns all TI-z80 calculators, except TI-85 and TI-86, that has a special RAM area directly mapped to the screen.
@@ Line 86: / Line 89: @@
 Many calculators recently manufactured by TI contained a buggy LCD driver, which had different (or varying) delays required to interface with it. Using the fast copy routines above with the LCDs will cause the LCD to display garbled information. However, we can do some additional hardware work to solve this problem, by waiting until we know the LCD is ready to accept a command:
 * Bit 7 of Port 10 tells us that the lcd can accept an instruction
 The TI-OS and other apps generally use port 2 but being that bit 7 is sign bit we can use that as faster method of waiting.
@@ Line 99: / Line 102: @@
 ;It must be noted that you cannot specify any other register. Only f works.
 ;You may have to add it in order for the routine to work.
   .addinstr IN	F,(C)	70ED	2	NOP	1
 SafeCopy:
-	di
+	di                 ;DI is only required if an interrupt will alter the lcd.
 	ld c,$10
 	ld a,$80
@@ Line 110: / Line 117: @@
 	jp m,setrow
 	out ($10),a
 	ld de,12
 	ld a,$20

← Older revision	Revision as of 19:49, 25 October 2009
(No difference)

@@ Line 117: / Line 117: @@
 	jp m,col
 	out ($10),a
-	ex af,af'
+	push af
 	ld b,64
 row:
@@ Line 127: / Line 127: @@
 	add hl,de
 	djnz row
-	ex af,af'
+	pop af
 	dec h
 	dec h

@@ Line 97: / Line 97: @@
+;
 ;in f,(c) is an unofficial instruction.
 ;You may have to add it in order for the routine to work.