mirror of
https://github.com/irmen/prog8.git
synced 2024-07-10 08:28:57 +00:00
43 lines
1.1 KiB
Lua
43 lines
1.1 KiB
Lua
%import textio
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main {
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sub crc32(uword data, uword length) {
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; because prog8 doesn't have 32 bits integers, we have to split up the calucation over 2 words.
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; result in cx16.r0 (high word) and cx1.r1 (low word).
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cx16.r0 = 0
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cx16.r1 = 0
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repeat length {
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cx16.r0 ^= @(data) << $0008
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repeat 8 {
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if cx16.r0 & $8000 {
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sys.clear_carry()
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rol(cx16.r1)
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rol(cx16.r0)
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cx16.r0 ^= $04c1
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cx16.r1 ^= $1db7
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}
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else {
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sys.clear_carry()
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rol(cx16.r1)
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rol(cx16.r0)
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}
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}
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data++
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}
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cx16.r0 ^= $ffff
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cx16.r1 ^= $ffff
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}
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sub start() {
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txt.print("calculating...")
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c64.SETTIM(0,0,0)
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crc32($e000, $2000)
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txt.print_uwhex(cx16.r0, true)
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txt.print_uwhex(cx16.r1, false)
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txt.nl()
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txt.print_uw(c64.RDTIM16())
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txt.print(" jiffies")
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sys.wait(100)
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}
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}
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