47 lines
2.4 KiB
C
47 lines
2.4 KiB
C
// SHA-256 block compression for frontend/sha256.js (built to WebAssembly).
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// No libc, no allocation: JS owns the memory layout.
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// state (8 x u32) at STATE
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// input (N x 64 B) at DATA
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// Build: scripts/build-sha256-wasm.sh (writes frontend/sha256-wasm.js)
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typedef unsigned int u32;
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typedef unsigned char u8;
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static const u32 K[64] = {
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0x428a2f98,0x71374491,0xb5c0fbcf,0xe9b5dba5,0x3956c25b,0x59f111f1,0x923f82a4,0xab1c5ed5,
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0xd807aa98,0x12835b01,0x243185be,0x550c7dc3,0x72be5d74,0x80deb1fe,0x9bdc06a7,0xc19bf174,
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0xe49b69c1,0xefbe4786,0x0fc19dc6,0x240ca1cc,0x2de92c6f,0x4a7484aa,0x5cb0a9dc,0x76f988da,
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0x983e5152,0xa831c66d,0xb00327c8,0xbf597fc7,0xc6e00bf3,0xd5a79147,0x06ca6351,0x14292967,
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0x27b70a85,0x2e1b2138,0x4d2c6dfc,0x53380d13,0x650a7354,0x766a0abb,0x81c2c92e,0x92722c85,
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0xa2bfe8a1,0xa81a664b,0xc24b8b70,0xc76c51a3,0xd192e819,0xd6990624,0xf40e3585,0x106aa070,
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0x19a4c116,0x1e376c08,0x2748774c,0x34b0bcb5,0x391c0cb3,0x4ed8aa4a,0x5b9cca4f,0x682e6ff3,
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0x748f82ee,0x78a5636f,0x84c87814,0x8cc70208,0x90befffa,0xa4506ceb,0xbef9a3f7,0xc67178f2 };
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#define ROR(x,n) (((x) >> (n)) | ((x) << (32 - (n))))
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__attribute__((export_name("compress")))
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void compress(u32 *state, const u8 *data, u32 blocks) {
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u32 W[64];
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while (blocks--) {
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for (int i = 0; i < 16; i++, data += 4)
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W[i] = ((u32)data[0] << 24) | ((u32)data[1] << 16) | ((u32)data[2] << 8) | data[3];
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for (int i = 16; i < 64; i++) {
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u32 s0 = ROR(W[i-15],7) ^ ROR(W[i-15],18) ^ (W[i-15] >> 3);
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u32 s1 = ROR(W[i-2],17) ^ ROR(W[i-2],19) ^ (W[i-2] >> 10);
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W[i] = W[i-16] + s0 + W[i-7] + s1;
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}
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u32 a=state[0],b=state[1],c=state[2],d=state[3],e=state[4],f=state[5],g=state[6],h=state[7];
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// 8 rounds per iteration with the variables renamed instead of shuffled.
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#define RND(a,b,c,d,e,f,g,h,i) do { \
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u32 t1 = h + (ROR(e,6) ^ ROR(e,11) ^ ROR(e,25)) + (g ^ (e & (f ^ g))) + K[i] + W[i]; \
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u32 t2 = (ROR(a,2) ^ ROR(a,13) ^ ROR(a,22)) + ((a & b) | (c & (a | b))); \
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d += t1; h = t1 + t2; } while (0)
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for (int i = 0; i < 64; i += 8) {
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RND(a,b,c,d,e,f,g,h,i); RND(h,a,b,c,d,e,f,g,i+1);
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RND(g,h,a,b,c,d,e,f,i+2); RND(f,g,h,a,b,c,d,e,i+3);
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RND(e,f,g,h,a,b,c,d,i+4); RND(d,e,f,g,h,a,b,c,i+5);
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RND(c,d,e,f,g,h,a,b,i+6); RND(b,c,d,e,f,g,h,a,i+7);
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}
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state[0]+=a; state[1]+=b; state[2]+=c; state[3]+=d; state[4]+=e; state[5]+=f; state[6]+=g; state[7]+=h;
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}
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}
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