Apple-2-SW/apple2_hgr_font_tutorial
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Fix bogus .ORG directive to ORG

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michaelangel007 2016-01-10 20:02:51 -08:00
parent ae78c1b7b6
commit 8c4c00cc24
1 changed files with 13 additions and 12 deletions
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@ -616,13 +616,13 @@ Here's the disassembly of our (hard-coded) DrawChar() program:
```assembly ```assembly
; FUNC: DrawChar() ; FUNC: DrawChar()
; NOTES: A, X, Y is destroyed ; NOTES: A, X, Y is destroyed
.ORG $0300 ORG $0300
300: JSR ScreenPtrToTempPtr 300: JSR ScreenPtrToTempPtr
303: LDA #00 ; glyph 'c' to draw (not used yet) 303: LDA #00 ; glyph 'c' to draw (not used yet)
305: LDY #00 ; Y = column to draw at (hard-coded) 305: LDY #00 ; Y = column to draw at (hard-coded)
307: JMP _DrawChar 307: JMP _DrawChar
.ORG $0352 ORG $0352
352: _DrawChar 352: _DrawChar
352: LDX #0 352: LDX #0
354: .1 LDA $6200,X ; A = font[ offset + i ] 354: .1 LDA $6200,X ; A = font[ offset + i ]
@ -709,7 +709,7 @@ After drawing a character with `DrawChar()` it is handy if we can advance both:
; OUTPUT: Y-Register (column) is incremented ; OUTPUT: Y-Register (column) is incremented
; Increment the cursor column and move the destination screen pointer back ; Increment the cursor column and move the destination screen pointer back
; up 8 scan lines previously to what it was when DrawChar() was called. ; up 8 scan lines previously to what it was when DrawChar() was called.
.ORG $0370 ORG $0370
370:C8 INY 370:C8 INY
371:18 CLC 371:18 CLC
372:A5 F6 LDA $F6 372:A5 F6 LDA $F6
@ -834,7 +834,7 @@ Our prefix code to setup the source address becomes:
; PARAM: A = glyph to draw ; PARAM: A = glyph to draw
; PARAM: Y = column to draw at; $0 .. $27 (Columns 0 .. 39) (not modified) ; PARAM: Y = column to draw at; $0 .. $27 (Columns 0 .. 39) (not modified)
; NOTES: X is destroyed ; NOTES: X is destroyed
.ORG $033B ORG $033B
33B:48 PHA ; push c = %PQRSTUVW to draw 33B:48 PHA ; push c = %PQRSTUVW to draw
33C:29 1F AND #1F ; = %000STUVW R=0, Optimization: implicit CLC 33C:29 1F AND #1F ; = %000STUVW R=0, Optimization: implicit CLC
33E:0A ASL ; c * 2 %00STUVW0 33E:0A ASL ; c * 2 %00STUVW0
@ -977,12 +977,12 @@ Let's fix it up to print the hex value of the current character we are inspectin
1048:29 0F AND #F ; base 16 1048:29 0F AND #F ; base 16
104A:AA TAX ; 104A:AA TAX ;
104B:20 66 03 JSR ScreenPtrToTempPtr 104B:20 66 03 JSR ScreenPtrToTempPtr
104E:BD 58 10 LDA $1058,X ; nibble to ASCII 104E:BD 58 10 LDA NIB2HEX,X ; nibble to ASCII
1051:C8 INY ; IncCursorCol() 1051:C8 INY ; IncCursorCol()
1052:20 3B 03 JSR $033B ; DrawCharCol() 1052:20 3B 03 JSR $033B ; DrawCharCol()
1055:60 RTS 1055:60 RTS
.ORG $358 ORG $358
1058:30 31 32 33 ASC "0123456789ABCDEF" 1058:30 31 32 33 NIB2HEX ASC "0123456789ABCDEF"
105C:34 35 36 37 105C:34 35 36 37
1060:38 39 41 42 1060:38 39 41 42
1064:43 44 45 46 1064:43 44 45 46
@ -1242,7 +1242,7 @@ This is a little clunky but it is progress. Let's write the new SetCursorColRow(
; PARAM: Y = row to draw at; $0 .. $17 (Rows 0 .. 23) (not modified) ; PARAM: Y = row to draw at; $0 .. $17 (Rows 0 .. 23) (not modified)
; NOTES: Version 3! X and Y is swapped from earlier version! ; NOTES: Version 3! X and Y is swapped from earlier version!
; [$F5] = HgrLo[ Y ] + ScreenLo + X ; [$F5] = HgrLo[ Y ] + ScreenLo + X
.ORG $0379 ORG $0379
379:86 F5 STX $F5 379:86 F5 STX $F5
37B:B9 00 64 LDA HgrLo,Y ; HgrLo[ row ] 37B:B9 00 64 LDA HgrLo,Y ; HgrLo[ row ]
37E:18 CLC 37E:18 CLC
@ -1268,10 +1268,10 @@ Enter in:
Now that we have the basic print char working lets extend it to print a C-style string (one that is zero terminated.) Now that we have the basic print char working lets extend it to print a C-style string (one that is zero terminated.)
```assembly ```assembly
; FUNC: DrawString( *text ) = $038E ; FUNC: DrawString( *text )
; PARAM: X = High byte of string address ; PARAM: X = High byte of string address
; PARAM: Y = Low byte of string address ; PARAM: Y = Low byte of string address
.ORG $038E ORG $038E
38E:84 F0 STY $F0 38E:84 F0 STY $F0
390:86 F1 STX $F1 390:86 F1 STX $F1
392:A0 00 LDY #0 392:A0 00 LDY #0
@ -1461,7 +1461,7 @@ And here is the assembly:
; DATA: ; DATA:
; $6000.$63FF Font 7x8 Data ; $6000.$63FF Font 7x8 Data
; $6400.$642F HgrLo, HgrHi table for every 8 scanlines ; $6400.$642F HgrLo, HgrHi table for every 8 scanlines
.ORG $1300 ORG $1300
1300:A9 00 LDA #0 1300:A9 00 LDA #0
1302:85 F3 STA row 1302:85 F3 STA row
1304:85 E5 STA $E5 1304:85 E5 STA $E5
@ -1821,7 +1821,8 @@ Sweet !
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.) 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.)
```assembly ```assembly
; FUNC: ScrollHgrUpPixel() = $1400 ; FUNC: ScrollHgrUpPixel()
ORG $1400
1400: LDX #27 ; 39 columns ; Src Y Dst Y 1400: LDX #27 ; 39 columns ; Src Y Dst Y
1402: .1 LDA $2400,X : STA $2000,X ; [ 1] -> [ 0] 1402: .1 LDA $2400,X : STA $2000,X ; [ 1] -> [ 0]
1408: LDA $2800,X : STA $2400,X ; [ 2] -> [ 1] 1408: LDA $2800,X : STA $2400,X ; [ 2] -> [ 1]