32 lines
829 B
Forth
32 lines
829 B
Forth
# Draw pixels in response to keyboard events, starting from the top-left
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# and in raster order.
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#
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# To build a disk image:
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# ./translate ex3.mu # emits code.img
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# To run:
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# qemu-system-i386 code.img
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# Or:
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# bochs -f bochsrc # bochsrc loads code.img
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#
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# Expected output: a new green pixel starting from the top left corner of the
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# screen every time you press a key (letter or digit)
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fn main screen: (addr screen), keyboard: (addr keyboard), data-disk: (addr disk) {
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var x/ecx: int <- copy 0
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var y/edx: int <- copy 0
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{
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var key/eax: byte <- read-key keyboard
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compare key, 0
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loop-if-= # busy wait
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pixel-on-real-screen x, y, 0x31/green
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x <- increment
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compare x, 0x400/screen-width=1024
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{
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break-if-<
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y <- increment
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x <- copy 0
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}
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loop
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}
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}
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