52 lines
1.6 KiB
Forth
52 lines
1.6 KiB
Forth
# Demo of reading and writing to disk.
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#
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# Steps for trying it out:
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# 1. Translate this example into a disk image code.img.
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# ./translate ex9.mu
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# 2. Build a second disk image data.img containing some text.
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# dd if=/dev/zero of=data.img count=20160
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# echo 'abc def ghi' |dd of=data.img conv=notrunc
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# 3. Familiarize yourself with how the data disk looks within xxd:
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# xxd data.img |head
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# 4. Run in an emulator, either Qemu or Bochs.
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# qemu-system-i386 -hda code.img -hdb data.img
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# bochs -f bochsrc.2disks
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# 5. Exit the emulator.
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# 6. Notice that the data disk now contains the word count of the original text.
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# xxd data.img |head
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fn main screen: (addr screen), keyboard: (addr keyboard), data-disk: (addr disk) {
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var text-storage: (stream byte 0x200)
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var text/esi: (addr stream byte) <- address text-storage
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load-sectors data-disk, 0/lba, 1/num-sectors, text
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var word-count/eax: int <- word-count text
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var result-storage: (stream byte 0x10)
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var result/edi: (addr stream byte) <- address result-storage
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write-int32-decimal result, word-count
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store-sectors data-disk, 0/lba, 1/num-sectors, result
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}
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fn word-count in: (addr stream byte) -> _/eax: int {
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var result/edi: int <- copy 0
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{
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var done?/eax: boolean <- stream-empty? in
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compare done?, 0/false
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break-if-!=
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var g/eax: grapheme <- read-grapheme in
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{
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compare g, 0x20/space
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break-if-!=
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result <- increment
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}
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{
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compare g, 0xa/newline
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break-if-!=
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result <- increment
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}
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loop
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}
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return result
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}
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