Apple-2-SW/apple2_hgr_font_tutorial
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Fix DemoCharInspect assembly source

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Michaelangel007 2016-01-27 20:21:22 -08:00
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README.md
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@ -1,6 +1,6 @@
#Apple ]\[ //e HGR Font 6502 Assembly Language Tutorial
Revision: 57, Jan 27, 2016.
Revision: 58, Jan 27, 2016.
# Table of Contents
@ -1518,12 +1518,13 @@ Listing Demo 3a:
```assembly
; FUNC: DemoCharInspect()
KEYBOARD EQU $C000
KEYSTROBE EQU $C010
HgrLo EQU $F5
HgrHi EQU $F6
glyph EQU $FE
KEYBOARD EQU $C000
KEYSTROBE EQU $C010
DrawChar EQU $310
ORG $1000
1000: DemoCharInspect
@ -1531,27 +1532,27 @@ Listing Demo 3a:
1002:85 FE STA glyph ; save which glyph to draw
1004:A9 00 .1 LDA #0 ; screen = 0x2000
1006:85 F5 STA HgrLo ;
1008:A9 20 LDA #20 ;
1008:A9 20 LDA #$20 ; HGR Page 1
100A:85 F6 STA HgrHi ;
100C:A5 FE LDA glyph ; A = glyph
100E:A0 00 LDY #00 ; Y = col
1010:20 10 03 JSR PrintChar
1010:20 10 03 JSR DrawChar
1013:AD 00 C0 .2 LDA KEYBOARD ; read A=key
1016:10 FB BMI .2 ; no key?
1016:10 FB BPL .2 ; no key?
1018:8D 10 C0 STA KEYSTROBE ; debounce key
101B:C9 88 CMP #88 ; key == <-- ?
101B:C9 88 CMP #$88 ; key == <-- ?
101D:D0 0A BNE .4 ;
101F:C6 FE DEC glyph ; yes, --glyph
1021:A5 FE .3 LDA glyph ; glyph &= 0x7F
1023:29 7F AND #7F ;
1023:29 7F AND #$7F ;
1025:85 FE STA glyph ;
1027:10 DB BPL .1 ; always branch, draw prev char
1029:C9 95 .4 CMP #95 ; key == --> ?
1029:C9 95 .4 CMP #$95 ; key == --> ?
102B:D0 05 BNE .5 ;
102D:E6 FE INC glyph ; yes, ++glyph
102F:18 CLC ; always branch
1030:90 EF BCC .3 ; draw prev char
1032:C9 9B .5 CMP #9B ; key == ESC ?
1032:C9 9B .5 CMP #$9B ; key == ESC ?
1034:D0 DD BNE .2 ;
1036:60 RTS ; yes, exit
```