mirror of
https://github.com/libretro/bsnes-libretro.git
synced 2024-11-23 08:59:40 +00:00
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.]
66 lines
1.7 KiB
C++
66 lines
1.7 KiB
C++
#pragma once
|
|
|
|
//error detection code
|
|
|
|
namespace nall::CD::EDC {
|
|
|
|
//polynomial(x) = (x^16 + x^15 + x^2 + 1) * (x^16 + x^2 + x + 1)
|
|
inline auto polynomial(uint8_t x) -> uint32_t {
|
|
static uint32_t lookup[256]{};
|
|
static bool once = false;
|
|
if(!once) { once = true;
|
|
for(uint n : range(256)) {
|
|
uint32_t edc = n;
|
|
for(uint b : range(8)) edc = edc >> 1 ^ (edc & 1 ? 0xd8018001 : 0);
|
|
lookup[n] = edc;
|
|
}
|
|
}
|
|
return lookup[x];
|
|
}
|
|
|
|
//
|
|
|
|
inline auto create(array_view<uint8_t> input) -> uint32_t {
|
|
uint32_t sum = 0;
|
|
for(auto& byte : input) sum = sum >> 8 ^ polynomial(sum ^ byte);
|
|
return sum;
|
|
}
|
|
|
|
inline auto create(array_view<uint8_t> input, array_span<uint8_t> output) -> bool {
|
|
if(output.size() != 4) return false;
|
|
auto sum = create(input);
|
|
output[0] = sum >> 0;
|
|
output[1] = sum >> 8;
|
|
output[2] = sum >> 16;
|
|
output[3] = sum >> 24;
|
|
return true;
|
|
}
|
|
|
|
inline auto createMode1(array_span<uint8_t> sector) -> bool {
|
|
if(sector.size() != 2352) return false;
|
|
return create({sector, 2064}, {sector + 2064, 4});
|
|
}
|
|
|
|
//
|
|
|
|
inline auto verify(array_view<uint8_t> input, uint32_t edc) -> bool {
|
|
return edc == create(input);
|
|
}
|
|
|
|
inline auto verify(array_view<uint8_t> input, array_view<uint8_t> compare) -> bool {
|
|
if(compare.size() != 4) return false;
|
|
auto sum = create(input);
|
|
if(compare[0] != uint8_t(sum >> 0)) return false;
|
|
if(compare[1] != uint8_t(sum >> 8)) return false;
|
|
if(compare[2] != uint8_t(sum >> 16)) return false;
|
|
if(compare[3] != uint8_t(sum >> 24)) return false;
|
|
return true;
|
|
}
|
|
|
|
inline auto verifyMode1(array_view<uint8_t> sector) -> bool {
|
|
if(sector.size() != 2352) return false;
|
|
return verify({sector, 2064}, {sector + 2064, 4});
|
|
}
|
|
|
|
}
|