Apple-2-SW/apple2_hgr_font_tutorial
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Cleanup table header, and Ex. 2 hint

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michaelangel007 2016-01-10 14:50:30 -08:00
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@ -1294,8 +1294,8 @@ For our final trick we are going to copy the characters off the text screen onto
The text screen, like the HGR screen, is also non-linear, and also broken up into a triad:
|Row|Row2TextAddr|Row2HgrAddr|
|--:|:----:|:------:|
|Row|Text Addrress|HGR Address|
|--:|:----:|:----:|
| 0 | $400 |$2000|
| 1 | $480 |$2080|
| 2 | $500 |$2100|
@ -1427,13 +1427,15 @@ Hey! Homework? Yes, the only (true) way to demonstrate you understand the theo
* one scan line (1 pixel)
Hint: For scrolling up one pixel we can spot the pattern if we inspect the memory flow of how pixels get shuffled around:
Hint: For scrolling up one pixel we can spot the pattern if we inspect
the memory flow of how pixels get shuffled around:
40 bytes from $2400.$2427 -> $2000.$2027
40 bytes from $2800.$2827 -> $2400.$2427
etc
Don't forget that you only need to copy 191 rows, not 192, since the very bottom scanline should be "blank."
Don't forget that you only need to copy 191 rows, not 192, since the
very bottom scanline should be "blank."
## Conclusion