From f3f15cfd25dc5379ca48021884f4b96471dd895e Mon Sep 17 00:00:00 2001
From: Greg King <gregdk@users.sf.net>
Date: Sat, 12 Oct 2019 04:01:03 -0400
Subject: [PATCH 060/170] Fixed problems with the Atari Lynx's TGI driver.
* The sprite-types for black and transparent backgrounds were swapped.
* A filler-byte for text output isn't printed. (A hardware bug might not need that work-around in most cases.)
---
libsrc/lynx/tgi/lynx-160-102-16.s | 52 +++++++++++++++++--------------
1 file changed, 28 insertions(+), 24 deletions(-)
diff --git a/libsrc/lynx/tgi/lynx-160-102-16.s b/libsrc/lynx/tgi/lynx-160-102-16.s
index 04bdaae0..0728e687 100644
--- a/libsrc/lynx/tgi/lynx-160-102-16.s
+++ b/libsrc/lynx/tgi/lynx-160-102-16.s
@@ -1,10 +1,10 @@
;
; Graphics driver for the 160x102x16 mode on the Lynx.
;
-; All the drawing functions are simply done by sprites as the sprite
+; All the drawing functions simply are done by sprites, as the sprite
; engine is the only way to do fast graphics on a Lynx.
;
-; This code is written by Karri Kaksonen, 2004 for the cc65 compiler.
+; This code was written by Karri Kaksonen, 2004 for the cc65 compiler.
;
.include "zeropage.inc"
@@ -104,8 +104,10 @@ BGINDEX: .res 1 ; Pen to use for text background
DRAWPAGE: .res 1
SWAPREQUEST: .res 1
+; 8 rows with (one offset-byte plus 20 character bytes plus one fill-byte) plus one 0-offset-byte.
+; (As an experiment, the fill-byte isn't being generated.
+; It might not be needed to work around a Suzy bug.)
text_bitmap: .res 8*(1+20+1)+1
-; 8 rows with (one offset-byte plus 20 character bytes plus one fill-byte) plus one 0-offset-byte
; Constants and tables
@@ -830,7 +832,7 @@ TEXTSTYLE:
; ------------------------------------------------------------------------
; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
-; current text style. The text to output is given as a zero terminated
+; current text style. The text to output is given as a zero-terminated
; string with address in ptr3.
;
; Must set an error code: NO
@@ -842,12 +844,11 @@ OUTTEXT:
lda TEXTMAGY
sta text_sy+1
- stz text_sprite ; Set normal sprite
lda BGINDEX
- bne @L1
- lda #4
- sta text_sprite ; Set opaque sprite
+ beq @L1 ; Choose opaque black sprite?
+ lda #$04 ; No, choose normal sprite
@L1:
+ sta text_sprite
lda DRAWINDEX ; Set color
asl
asl
@@ -875,15 +876,18 @@ OUTTEXT:
ldy #20
@L3:
sty STRLEN
+ tya
bne @L4
- rts ; Zero length string
+ rts ; Zero-length string
@L4:
iny ; Prepare text_bitmap
- iny
+
+; The next instruction is commented because the code won't include a fill-byte.
+; iny
sty STROFF
ldy #8-1 ; 8 pixel lines per character
- ldx #0
+ ldx #$00
clc
@L5:
lda STROFF
@@ -891,45 +895,45 @@ OUTTEXT:
txa
adc STROFF
tax
- lda #$ff
- sta text_bitmap-1,x
+
+; This was the fill-byte.
+; lda #$FF
+; sta text_bitmap-1,x
dey
bpl @L5
stz text_bitmap,x
stz tmp2
- iny
+ iny ;(ldy #$00)
@L6:
lda (STRPTR),y
sty tmp1
- sec ; (ch-' ') * 8
- sbc #32
- stz FONTOFF
+ sub #' ' ; (ch - ' ') * 8
stz FONTOFF+1
asl
asl
rol FONTOFF+1
asl
rol FONTOFF+1
- clc ; Choose font
- adc #<font
+ ;clc ; (cleared by rol)
+ adc #<font ; Choose font
sta FONTOFF
lda FONTOFF+1
adc #>font
sta FONTOFF+1
-; and now copy the 8 bytes of that char
+; And now, copy the 8 bytes of that glyph.
ldx tmp2
inx
stx tmp2
-; draw char from top to bottom, reading char-data from offset 8-1 to offset 0
+; Draw char. from top to bottom, reading char-data from offset 8-1 to offset 0.
ldy #8-1
@L7:
- lda (FONTOFF),y ; *chptr
- sta text_bitmap,x ;textbuf[y*(1+len+1)+1+x]
+ lda (FONTOFF),y ; *chptr
+ sta text_bitmap,x ; textbuf[y*(1+len+1)+1+x]
txa
adc STROFF
@@ -938,7 +942,7 @@ OUTTEXT:
dey
bpl @L7
- ; goto next char
+ ; Goto next char.
ldy tmp1
iny
dec STRLEN
--
2.26.0