Apple-2-SW/apple2_hgr_font_tutorial
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Added CharInspect assembly source

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Michaelangel007 2016-01-27 20:41:38 -08:00
parent e03f7d3c85
commit 530b473ad2
1 changed files with 55 additions and 0 deletions
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asm/charinspect.s Normal file
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__MAIN = $1000
.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
DemoCharInspect:
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
.a LDA #0 ; screen = 0x2000
STA HgrLo ;
LDA #$20 ; HGR Page 1
STA HgrHi ;
LDA glyph ; A = glyph
LDY #00 ; Y = col
JSR DrawChar
.b LDA KEYBOARD ; read A=key
BPL .b ; no key?
STA KEYSTROBE ; debounce key
CMP #$88 ; key == <-- ? CTRL-H
BNE .d ;
DEC glyph ; yes, --glyph
.c LDA glyph ; glyph &= 0x7F
AND #$7F ;
STA glyph ;
BPL .a ; always branch, draw prev char
.d CMP #$95 ; key == --> ? CTRL-U
BNE .e ;
INC glyph ; yes, ++glyph
CLC ; always branch
BCC .c ; draw prev char
.e CMP #$9B ; key == ESC ?
BNE .b ;
RTS ; yes, exit
PrintChar
__END: