Apple-2-SW/apple2_hgr_font_tutorial
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Add cycle timings

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michaelangel007 2016-01-13 22:01:18 -08:00
parent 31f9edaecf
commit bdcaf29228
1 changed files with 22 additions and 3 deletions
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README.md
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@ -1333,11 +1333,28 @@ Let's code this up:
Since we'll re-use our existing font drawing code `_DrawChar1` at $034C it is always a good idea to document why there is no `RTS` at the end.
Here is a comparison between the original and final version:
Here is a comparison between the original and final version (clock cycle timings are the #'s):
ORG $0335 (old) ORG $033A (new)
3 PHA 2 ROL
2 AND #1F 2 ROL
2 ASL 2 ROL
2 ASL 2 TAX
2 ASL 2 AND #F8
2 ADC #<Font 4 STA _LoadFont+1
4 STA _LoadFont+1 2 TXA
4 PLA 2 AND #3
2 AND #E0 2 ROL
2 ROL 3 ADC #>Font
2 ROL 4 STA _LoadFont+2
2 ROL -
2 ROL -
2 ADC #>Font -
4 STA _LoadFont+2 -
Original Final
Bytes 23 18
Cycles ? TODO ? TODO
Cycles 37 27
Much better!!!
@ -2624,9 +2641,11 @@ That's all folks! Now go write some cool font blitter code.
# TODO:
- [x] Screenshots!
- [ ] Cleanup all assembly for consistent indentation and alignment (IN PROGRESS)
- [x] Cleanup all assembly for consistent indentation and alignment
- [ ] Binary code for 300.bin and 1000.bin so you can load it directly into the emulator
- [ ] Disk image: `HGR_FONT.DSK` (In progress)
- [x] Count cycles of old and new DrawCharCol Address Calculation
- [ ] Alternative fonts
- [ ] Re-engineer Codepage 437 Font to 7x8 cells:
![font_codepage_437_8x8.png](font_codepage_437_8x8.png)
- [ ] Double Hi-Res