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     #

+        ;clc                    ; (cleared by rol)

+        adc     #

         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