Apple-2-SW/apple2_hgr_font_tutorial
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Add proper .ORG to DrawChar()

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michaelangel007 2016-01-10 19:25:08 -08:00
parent 23a79b0a88
commit 2177111f62
1 changed files with 2 additions and 3 deletions
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README.md
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@ -616,12 +616,13 @@ Here's the disassembly of our (hard-coded) DrawChar() program:
```assembly
; FUNC: DrawChar() = $0300
; NOTES: A, X, Y is destroyed
.ORG $300
300: JSR ScreenPtrToTempPtr
303: LDA #00 ; glyph 'c' to draw (not used yet)
305: LDY #00 ; Y = column to draw at (hard-coded)
307: JMP _DrawChar
307 .ORG $0352
.ORG $352
352: _DrawChar:
352: LDX #0
354: .1 LDA $6200,X ; A = font[ offset + i ]
@ -828,7 +829,6 @@ However we can save one instruction (and 2 cycles) if we optimize `c/32` to use
Our prefix code to setup the source address becomes:
```assembly
; FUNC: DrawCharCol( c, col ) = $03BB
; FUNC: DrawCharCol( c, col ) = $03BB
; PARAM: A = glyph to draw
; PARAM: Y = column to draw at; $0 .. $27 (Columns 0 .. 39) (not modified)
@ -1047,7 +1047,6 @@ Let's use IncCursorCol() to automatically advance the cusor. We'll also add a s
1064:43 44 45 46
```
Enter in:
310:20 3B 03 4C 70 03