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Fix bogus .ORG directive to ORG
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README.md
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README.md
@ -616,13 +616,13 @@ Here's the disassembly of our (hard-coded) DrawChar() program:
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```assembly
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; FUNC: DrawChar()
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; NOTES: A, X, Y is destroyed
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.ORG $0300
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ORG $0300
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300: JSR ScreenPtrToTempPtr
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303: LDA #00 ; glyph 'c' to draw (not used yet)
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305: LDY #00 ; Y = column to draw at (hard-coded)
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307: JMP _DrawChar
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.ORG $0352
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ORG $0352
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352: _DrawChar
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352: LDX #0
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354: .1 LDA $6200,X ; A = font[ offset + i ]
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@ -709,7 +709,7 @@ After drawing a character with `DrawChar()` it is handy if we can advance both:
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; OUTPUT: Y-Register (column) is incremented
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; Increment the cursor column and move the destination screen pointer back
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; up 8 scan lines previously to what it was when DrawChar() was called.
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.ORG $0370
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ORG $0370
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370:C8 INY
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371:18 CLC
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372:A5 F6 LDA $F6
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@ -834,7 +834,7 @@ Our prefix code to setup the source address becomes:
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; PARAM: A = glyph to draw
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; PARAM: Y = column to draw at; $0 .. $27 (Columns 0 .. 39) (not modified)
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; NOTES: X is destroyed
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.ORG $033B
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ORG $033B
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33B:48 PHA ; push c = %PQRSTUVW to draw
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33C:29 1F AND #1F ; = %000STUVW R=0, Optimization: implicit CLC
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33E:0A ASL ; c * 2 %00STUVW0
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@ -977,12 +977,12 @@ Let's fix it up to print the hex value of the current character we are inspectin
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1048:29 0F AND #F ; base 16
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104A:AA TAX ;
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104B:20 66 03 JSR ScreenPtrToTempPtr
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104E:BD 58 10 LDA $1058,X ; nibble to ASCII
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104E:BD 58 10 LDA NIB2HEX,X ; nibble to ASCII
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1051:C8 INY ; IncCursorCol()
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1052:20 3B 03 JSR $033B ; DrawCharCol()
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1055:60 RTS
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.ORG $358
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1058:30 31 32 33 ASC "0123456789ABCDEF"
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ORG $358
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1058:30 31 32 33 NIB2HEX ASC "0123456789ABCDEF"
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105C:34 35 36 37
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1060:38 39 41 42
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1064:43 44 45 46
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@ -1242,7 +1242,7 @@ This is a little clunky but it is progress. Let's write the new SetCursorColRow(
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; PARAM: Y = row to draw at; $0 .. $17 (Rows 0 .. 23) (not modified)
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; NOTES: Version 3! X and Y is swapped from earlier version!
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; [$F5] = HgrLo[ Y ] + ScreenLo + X
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.ORG $0379
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ORG $0379
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379:86 F5 STX $F5
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37B:B9 00 64 LDA HgrLo,Y ; HgrLo[ row ]
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37E:18 CLC
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@ -1268,10 +1268,10 @@ Enter in:
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Now that we have the basic print char working lets extend it to print a C-style string (one that is zero terminated.)
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```assembly
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; FUNC: DrawString( *text ) = $038E
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; FUNC: DrawString( *text )
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; PARAM: X = High byte of string address
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; PARAM: Y = Low byte of string address
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.ORG $038E
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ORG $038E
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38E:84 F0 STY $F0
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390:86 F1 STX $F1
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392:A0 00 LDY #0
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@ -1461,7 +1461,7 @@ And here is the assembly:
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; DATA:
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; $6000.$63FF Font 7x8 Data
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; $6400.$642F HgrLo, HgrHi table for every 8 scanlines
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.ORG $1300
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ORG $1300
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1300:A9 00 LDA #0
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1302:85 F3 STA row
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1304:85 E5 STA $E5
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@ -1821,7 +1821,8 @@ Sweet !
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Here's the (non-standard) assembly to scroll the HGR screen up one pixel: (I'm using the non-conventional `:` as an assembler end-of-statement sepearator to logically group the byte copies together.)
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```assembly
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; FUNC: ScrollHgrUpPixel() = $1400
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; FUNC: ScrollHgrUpPixel()
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ORG $1400
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1400: LDX #27 ; 39 columns ; Src Y Dst Y
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1402: .1 LDA $2400,X : STA $2000,X ; [ 1] -> [ 0]
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1408: LDA $2800,X : STA $2400,X ; [ 2] -> [ 1]
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