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https://github.com/bsnes-emu/bsnes.git
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559a6585ef
byuu says:
First 32 instructions implemented in the TLCS900H disassembler. Only 992
to go!
I removed the use of anonymous namespaces in nall. It was something I
rarely used, because it rarely did what I wanted.
I updated all nested namespaces to use C++17-style namespace Foo::Bar {}
syntax instead of classic C++-style namespace Foo { namespace Bar {}}.
I updated ruby::Video::acquire() to return a struct, so we can use C++17
structured bindings. Long term, I want to get away from all functions
that take references for output only. Even though C++ botched structured
bindings by not allowing you to bind to existing variables, it's even
worse to have function calls that take arguments by reference and then
write to them. From the caller side, you can't tell the value is being
written, nor that the value passed in doesn't matter, which is terrible.
110 lines
2.9 KiB
C++
110 lines
2.9 KiB
C++
#pragma once
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#include <nall/arithmetic.hpp>
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#include <nall/array-view.hpp>
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namespace nall::Cipher {
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//64-bit nonce; 64-bit x 64-byte (256GB) counter
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struct ChaCha20 {
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ChaCha20(uint256_t key, uint64_t nonce, uint64_t counter = 0) {
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static const uint128_t sigma = 0x6b20657479622d323320646e61707865_u128; //"expand 32-byte k"
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input[ 0] = sigma >> 0;
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input[ 1] = sigma >> 32;
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input[ 2] = sigma >> 64;
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input[ 3] = sigma >> 96;
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input[ 4] = key >> 0;
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input[ 5] = key >> 32;
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input[ 6] = key >> 64;
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input[ 7] = key >> 96;
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input[ 8] = key >> 128;
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input[ 9] = key >> 160;
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input[10] = key >> 192;
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input[11] = key >> 224;
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input[12] = counter >> 0;
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input[13] = counter >> 32;
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input[14] = nonce >> 0;
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input[15] = nonce >> 32;
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offset = 0;
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}
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auto encrypt(array_view<uint8_t> input) -> vector<uint8_t> {
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vector<uint8_t> output;
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while(input) {
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if(!offset) {
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cipher();
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increment();
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}
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auto byte = offset++;
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output.append(*input++ ^ (block[byte >> 2] >> (byte & 3) * 8));
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offset &= 63;
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}
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return output;
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}
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auto decrypt(array_view<uint8_t> input) -> vector<uint8_t> {
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return encrypt(input); //reciprocal cipher
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}
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//protected:
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inline auto rol(uint32_t value, uint bits) -> uint32_t {
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return value << bits | value >> 32 - bits;
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}
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auto quarterRound(uint32_t x[16], uint a, uint b, uint c, uint d) -> void {
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x[a] += x[b]; x[d] = rol(x[d] ^ x[a], 16);
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x[c] += x[d]; x[b] = rol(x[b] ^ x[c], 12);
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x[a] += x[b]; x[d] = rol(x[d] ^ x[a], 8);
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x[c] += x[d]; x[b] = rol(x[b] ^ x[c], 7);
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}
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auto cipher() -> void {
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memory::copy(block, input, 64);
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for(uint n : range(10)) {
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quarterRound(block, 0, 4, 8, 12);
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quarterRound(block, 1, 5, 9, 13);
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quarterRound(block, 2, 6, 10, 14);
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quarterRound(block, 3, 7, 11, 15);
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quarterRound(block, 0, 5, 10, 15);
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quarterRound(block, 1, 6, 11, 12);
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quarterRound(block, 2, 7, 8, 13);
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quarterRound(block, 3, 4, 9, 14);
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}
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}
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auto increment() -> void {
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for(uint n : range(16)) {
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block[n] += input[n];
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}
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if(!++input[12]) ++input[13];
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}
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uint32_t input[16];
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uint32_t block[16];
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uint64_t offset;
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};
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struct HChaCha20 : protected ChaCha20 {
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HChaCha20(uint256_t key, uint128_t nonce) : ChaCha20(key, nonce >> 64, nonce >> 0) {
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cipher();
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}
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auto key() const -> uint256_t {
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uint256_t key = 0;
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for(uint n : range(4)) key |= (uint256_t)block[ 0 + n] << (n + 0) * 32;
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for(uint n : range(4)) key |= (uint256_t)block[12 + n] << (n + 4) * 32;
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return key;
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}
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};
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//192-bit nonce; 64-bit x 64-byte (256GB) counter
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struct XChaCha20 : ChaCha20 {
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XChaCha20(uint256_t key, uint192_t nonce, uint64_t counter = 0):
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ChaCha20(HChaCha20(key, nonce).key(), nonce >> 128, counter) {
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}
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};
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}
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