Add asciitable asm source

2024-12-27 05:32:19 +00:00 · 2016-01-27 23:26:52 -08:00 · 2016-01-27 23:26:52 -08:00 · 2c15cf46f9
commit 2c15cf46f9
parent 5e8239fbb4
1 changed files with 60 additions and 0 deletions
--- a/asm/asciitable.s
+++ b/asm/asciitable.s
@ -0,0 +1,60 @@
+        __MAIN = $1080
+        .include "dos33.inc"
+        .include "ca65.inc"
+
+        KEYBOARD    = $C000
+        KEYSTROBE   = $C010
+        TXTCLR      = $C050 ; Mode Graphics
+        MIXCLR      = $C052 ; Full  screen
+        MIXSET      = $C053 ; Split screen
+        PAGE1       = $C054
+        HIRES       = $C057 ; Mode HGR
+
+        HgrLo       = $F5
+        HgrHi       = $F6
+        glyph       = $FE
+        DrawChar    = $310
+        HgrLoY      = $3A0
+        HgrHiY      = $3B8
+
+AsciiTable
+        BIT PAGE1       ; Page 1
+        BIT TXTCLR      ; not text, but graphics
+        BIT MIXSET      ; Split screen text/graphics
+        BIT HIRES       ; HGR, no GR
+
+        LDA #0          ; glyph=0
+        STA glyph       ; save which glyph to draw
+
+        LDY #8          ; Row=8
+_RowN
+        LDA HgrLoY,Y
+        STA HgrLo       ; Screen Address Lo
+        LDA HgrHiY,Y
+        ORA #$20        ; HGR Page 1
+        STA HgrHi       ; Screen Address Hi
+
+        LDY #00         ; Y = col
+_Glyph
+        LDA glyph       ; A = glyph
+        JSR DrawChar
+        INC glyph       ; yes, ++glyph
+        LDA glyph       ;
+        CMP #$20        ; done 16 chars?
+        BEQ _Row1
+        CMP #$40
+        BEQ _Row2
+        CMP #$60
+        BEQ _Row3
+        CMP #$80
+        BNE _Glyph      ;
+_Done   RTS             ; Optimization: BEQ _Row4
+_Row1   LDY #9
+        BNE _RowN
+_Row2   LDY #10
+        BNE _RowN
+_Row3   LDY #11
+        BNE _RowN
+
+__END:
+