mirror of
https://github.com/bsnes-emu/bsnes.git
synced 2025-08-16 06:54:08 +02:00
d87a0f633d
byuu says:
- bsnes: added video filters from bsnes v082
- bsnes: added ZSNES snow effect option when games paused or unloaded
(no, I'm not joking)
- bsnes: added 7-zip support (LZMA 19.00 SDK)
[Recent higan WIPs have also mentioned bsnes changes, although the higan code
no longer includes the bsnes code. These changes include:
- higan, bsnes: added EXLOROM, EXLOROM-RAM, EXHIROM mappings
- higan, bsnes: focus the viewport after leaving fullscreen exclusive
mode
- bsnes: re-added mightymo's cheat code database
- bsnes: improved make install rules for the game and cheat code
databases
- bsnes: delayed construction of hiro::Window objects to properly show
bsnes window icons
- Ed.]
36 lines
754 B
C++
36 lines
754 B
C++
#pragma once
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namespace nall::CD::Scrambler {
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//polynomial(x) = x^15 + x + 1
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inline auto polynomial(uint x) -> uint8_t {
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static uint8_t lookup[2340]{};
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static bool once = false;
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if(!once) { once = true;
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uint16_t shift = 0x0001;
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for(uint n : range(2340)) {
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lookup[n] = shift;
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for(uint b : range(8)) {
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bool carry = shift & 1 ^ shift >> 1 & 1;
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shift = (carry << 15 | shift) >> 1;
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}
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}
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}
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return lookup[x];
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}
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//
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inline auto transform(array_span<uint8_t> sector) -> bool {
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if(sector.size() == 2352) sector += 12; //header is not scrambled
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if(sector.size() != 2340) return false; //F1 frames only
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for(uint index : range(2340)) {
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sector[index] ^= polynomial(index);
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}
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return true;
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}
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}
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