mirror of
https://github.com/Michaelangel007/apple2_hgr_font_tutorial.git
synced 2024-11-22 03:30:50 +00:00
Fix EQU alignment
This commit is contained in:
parent
6c1a2695e2
commit
5c36f6b288
44
README.md
44
README.md
@ -1,6 +1,6 @@
|
||||
#Apple ]\[ //e HGR Font 6502 Assembly Language Tutorial
|
||||
|
||||
Revision: 56, Jan 27, 2016.
|
||||
Revision: 57, Jan 27, 2016.
|
||||
|
||||
# Table of Contents
|
||||
|
||||
@ -696,12 +696,12 @@ How did I know to use $0400 when going to the next line? One quirk of the HGR s
|
||||
Before we can start a simple `DrawChar(char c)` function, we also first need to assign some zero page memory locations for our static and temporary variables, our 16-bit address of where want to draw to. Since we also have our font data, we need a symbol for that too.
|
||||
|
||||
```assembly
|
||||
HgrLo EQU $E5 ; Low byte Pointer to screen destination
|
||||
HgrHi EQU $E6 ; High byte Pointer to screen destination
|
||||
TmpLo EQU $F5 ; Low byte Working pointer to screen byte
|
||||
TmpHi EQU $F6 ; High byte Working pointer to screen byte
|
||||
HgrLo EQU $E5 ; Low byte Pointer to screen destination
|
||||
HgrHi EQU $E6 ; High byte Pointer to screen destination
|
||||
TmpLo EQU $F5 ; Low byte Working pointer to screen byte
|
||||
TmpHi EQU $F6 ; High byte Working pointer to screen byte
|
||||
|
||||
Font EQU $6000
|
||||
Font EQU $6000
|
||||
```
|
||||
|
||||
Here's the disassembly of our (hard-coded) DrawChar() program:
|
||||
@ -1008,7 +1008,7 @@ Wait, you say! There IS a way to solve this problem -- and it doesn't take later
|
||||
Listing 4a:
|
||||
|
||||
```assembly
|
||||
TopHi EQU $FD
|
||||
TopHi EQU $FD
|
||||
|
||||
ORG $034C
|
||||
034C: _DrawChar1
|
||||
@ -1960,22 +1960,22 @@ Now that we have the basic print char working lets extend it to print a C-style
|
||||
Listing 12:
|
||||
|
||||
```assembly
|
||||
String EQU $F0
|
||||
String EQU $F0
|
||||
|
||||
; FUNC: DrawString( *text )
|
||||
; PARAM: X = High byte of string address
|
||||
; PARAM: Y = Low byte of string address
|
||||
037E: ORG $037E
|
||||
037E: DrawString
|
||||
037E:84 F0 STY String+0
|
||||
0380:86 F1 STX String+1
|
||||
0382:A0 00 LDY #0
|
||||
0384:B1 F0 .1 LDA (String),Y
|
||||
0386:F0 07 BEQ .2 ; null byte? Done
|
||||
0388:20 10 03 JSR DrawChar ; or DrawCharCol for speed
|
||||
038B:C0 28 CPY #40 ; col < 40?
|
||||
038D:90 F5 BCC .1
|
||||
038F:60 .2 RTS
|
||||
037E:84 F0 STY String+0
|
||||
0380:86 F1 STX String+1
|
||||
0382:A0 00 LDY #0
|
||||
0384:B1 F0 .1 LDA (String),Y
|
||||
0386:F0 07 BEQ .2 ; null byte? Done
|
||||
0388:20 10 03 JSR DrawChar ; or DrawCharCol for speed
|
||||
038B:C0 28 CPY #40 ; col < 40?
|
||||
038D:90 F5 BCC .1
|
||||
038F:60 .2 RTS
|
||||
```
|
||||
<hr>
|
||||
**AppleWin**:
|
||||
@ -2123,9 +2123,9 @@ And here is the assembly:
|
||||
; DATA:
|
||||
; $6000.$63FF Font 7x8 Data
|
||||
; $6400.$642F HgrLoY, HgrHiY table for every 8 scanlines
|
||||
1300: Txt EQU $F7
|
||||
1300: Txt EQU $F7
|
||||
ORG $1300
|
||||
1300: CopyTextToHgr
|
||||
1300: CopyTextToHgr
|
||||
1300:A9 00 LDA #0
|
||||
1302:85 F3 STA row
|
||||
1304:85 E5 STA $E5
|
||||
@ -2656,9 +2656,9 @@ However each HGR "text" line takes 8 scanlines (since our font cell is 7x8).
|
||||
We could code this up as:
|
||||
|
||||
```assembly
|
||||
Src EQU $F8
|
||||
Dst EQU $FA
|
||||
Tmp EQU $FC
|
||||
Src EQU $F8
|
||||
Dst EQU $FA
|
||||
Tmp EQU $FC
|
||||
|
||||
; NOTE: Requires $E6 to be initialized with $20 or $40 for graphics page
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user