Apple-2-SW/apple2_hgr_font_tutorial
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Short asciitable, don't hard-code starting row

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Michaelangel007 2016-01-28 00:14:53 -08:00
parent 8a5b55c971
commit a641b5bd18
2 changed files with 18 additions and 18 deletions
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36
asm/asciitable.s
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@ -13,21 +13,27 @@
HgrLo = $F5
HgrHi = $F6
glyph = $FE
row = $FF
DrawChar = $310
HgrLoY = $3A0
HgrHiY = $3B8
START_ROW = 0
AsciiTable
BIT PAGE1 ; Page 1
BIT TXTCLR ; not text, but graphics
BIT MIXSET ; Split screen text/graphics
BIT HIRES ; HGR, no GR
LDY #(START_ROW-1) & $FF
STY row
LDA #0 ; glyph=0
STA glyph ; save which glyph to draw
LDY #8 ; Row=8
_RowN
BIT PAGE1 ; Page 1
BIT TXTCLR ; not text, but graphics
BIT MIXSET ; Split screen text/graphics
BIT HIRES ; HGR, no GR
_NextRow
INC row
LDY row
LDA HgrLoY,Y
STA HgrLo ; Screen Address Lo
LDA HgrHiY,Y
@ -35,26 +41,20 @@ _RowN
STA HgrHi ; Screen Address Hi
LDY #00 ; Y = col
_Glyph
_NextCol
LDA glyph ; A = glyph
JSR DrawChar
INC glyph ; yes, ++glyph
LDA glyph ;
CMP #$20 ; done 16 chars?
BEQ _Row1
BEQ _NextRow
CMP #$40
BEQ _Row2
BEQ _NextRow
CMP #$60
BEQ _Row3
BEQ _NextRow
CMP #$80
BNE _Glyph ;
_Done RTS ; Optimization: BEQ _Row4
_Row1 LDY #9
BNE _RowN
_Row2 LDY #10
BNE _RowN
_Row3 LDY #11
BNE _RowN
BNE _NextCol
_Done RTS ; Optimization: BEQ _NextRow
__END:

BIN
bin/asciitable.bin
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