80 lines
1.9 KiB
Forth
80 lines
1.9 KiB
Forth
# https://adventofcode.com/2020/day/5
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#
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# To run (on Linux):
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# $ git clone https://github.com/akkartik/mu
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# $ cd mu
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# $ ./translate advent2020/5a.mu
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# $ ./a.elf < input
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#
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# You'll need to register to download the 'input' file for yourself.
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fn main -> _/ebx: int {
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var line-storage: (stream byte 0x10) # 16 bytes is enough
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var line/edx: (addr stream byte) <- address line-storage
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var max-seat-id/edi: int <- copy 0
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{
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# read line from stdin
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clear-stream line
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read-line-from-real-keyboard line
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print-stream-to-real-screen line
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# if line is empty (not even a newline), quit
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var done?/eax: boolean <- stream-empty? line
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compare done?, 0/false
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break-if-!=
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# process line
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var seat-id/eax: int <- convert-from-binary line
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compare seat-id, max-seat-id
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{
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break-if-<=
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max-seat-id <- copy seat-id
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}
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loop
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}
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print-int32-decimal 0, max-seat-id
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print-string 0, "\n"
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return 0
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}
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fn convert-from-binary in: (addr stream byte) -> _/eax: int {
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var result/edi: int <- copy 0
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var i/ecx: int <- copy 9 # loop counter and also exponent
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{
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compare i, 0
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break-if-<
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var c/eax: byte <- read-byte in
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#? print-string 0, "char: "
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#? {
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#? var c2/eax: int <- copy c
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#? print-int32-hex 0, c2
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#? }
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#? print-string 0, "\n"
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var bit/edx: int <- copy 0
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{
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compare c, 0x42/B
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break-if-!=
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bit <- copy 1
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}
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{
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compare c, 0x52/R
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break-if-!=
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bit <- copy 1
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}
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#? print-string 0, "bit: "
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#? print-int32-decimal 0, bit
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#? print-string 0, "\n"
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var bit-value/eax: int <- repeated-shift-left bit, i
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#? print-string 0, "bit value: "
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#? print-int32-decimal 0, bit-value
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#? print-string 0, "\n"
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result <- add bit-value
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#? print-string 0, "result: "
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#? print-int32-decimal 0, result
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#? print-string 0, "\n"
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i <- decrement
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loop
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}
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print-int32-decimal 0, result
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print-string 0, "\n"
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return result
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}
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