71 lines
2.4 KiB
Markdown
71 lines
2.4 KiB
Markdown
# PrintShop / MiniPix Viewer
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* 
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* 
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Utility to decode a PrintShop / MiniPix 88x52 monochrome imag written
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in 6502 assembly language for the Apple \]\[.
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By default MiniPix are loaded at $5800. File size is 572 ($23C).
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From UseNet this question was asked: _PrintShop graphics to DHR?_
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I really like this "puzzle" as there are 6 variations:
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* a) MiniPixToSrcBufHGR (Over-writes source minipix)
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* b) MiniPixToDstBufHGR (Unpacks to different buffer)
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* c) MiniPixToScreenHGR
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* d) MiniPixToSrcBufDHGR (Over-writes source minipix)
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* e) MiniPixToDstBufDHGR (Unpacks to different buffer)
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* f) MiniPixToScreenDHGR
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I was bored this weekend so I whipped up an implementation for:
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* (c) MiniPixToScreenHGR:
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# Pros
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+ Unpacks directly to the HGR screen
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+ Doesn't need any secondary buffers
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+ Source MiniPix image is left untouched
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+ Image is perfectly centered both horizontally and vertically
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(If you don't care about perfectly centered horizontally by being shifted
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over 1 pixel to the left then you can shave off 166 - 157 = 9 bytes. You
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will also need to fixup the Column2ColorHGR table.)
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+ Uses correct 2:3 aspect ratio
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+ Technically, the HGR screen does NOT need to be initialized, however it DOES
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call HGR @ $F3E2 though to in order to initialize a few zero page variables.
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# Meh
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o Uses a 7 byte look-up table for pixel doubling
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# Cons
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- Uses a crap ton of zero page variables -- 16 in total:
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$1C, $26, $27, $30, $E4 .. $E6, $F7 .. $FF
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- Requires Applesoft ROM to be banked in as it uses 2 ROM entry points:
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HGR, HPOSN.
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- Code size is 152 bytes. (Demo is 166 bytes.)
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```
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6000:20 e2 f3 8d 52 c0 a2 58 a0 00 86 f8 84 f7 a9 12
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6010:85 fc a0 00 84 e4 84 ff a2 34 a5 fc 20 17 f4 a8
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6020:85 fb 85 fd 18 a5 e5 65 26 85 26 a2 01 86 fe a9
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6030:01 85 fa b1 f7 85 f9 06 f9 a5 fd b0 05 1d 9f 60
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6040:85 fd e8 e0 04 f0 04 e0 07 d0 13 84 fb 20 8a 60
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6050:85 fd a4 fb e6 26 e0 07 d0 04 a2 00 86 fe 06 fa
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6060:90 d5 c8 84 fb c0 0b 90 c6 a5 fd 20 8a 60 e6 fc
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6070:e6 ff a6 ff e0 03 d0 a0 18 a9 0b 65 f7 85 f7 90
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6080:02 e6 f8 a5 fc c9 ae d0 8d 60 48 29 7f a0 00 91
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6090:26 68 2a a9 00 2a f0 06 e0 04 d0 02 a9 03 60 06
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60a0:18 60 80 0c 30 c0
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BSAVE MINIPIXVIEWER,A$6000,L$A6
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```
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It expects a PrintShop MiniPix (572 bytes) to be loaded at $5800.
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Demo disk and (Merlin32) assembly source included.
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