36 lines
1019 B
C
36 lines
1019 B
C
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#include "transpose.h"
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/* input: in, a 64x64 matrix over GF(2) */
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/* output: out, transpose of in */
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void PQCLEAN_MCELIECE348864F_VEC_transpose_64x64(uint64_t *out, const uint64_t *in) {
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int i, j, s, d;
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uint64_t x, y;
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uint64_t masks[6][2] = {
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{0x5555555555555555, 0xAAAAAAAAAAAAAAAA},
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{0x3333333333333333, 0xCCCCCCCCCCCCCCCC},
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{0x0F0F0F0F0F0F0F0F, 0xF0F0F0F0F0F0F0F0},
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{0x00FF00FF00FF00FF, 0xFF00FF00FF00FF00},
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{0x0000FFFF0000FFFF, 0xFFFF0000FFFF0000},
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{0x00000000FFFFFFFF, 0xFFFFFFFF00000000}
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};
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for (i = 0; i < 64; i++) {
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out[i] = in[i];
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}
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for (d = 5; d >= 0; d--) {
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s = 1 << d;
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for (i = 0; i < 64; i += s * 2) {
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for (j = i; j < i + s; j++) {
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x = (out[j] & masks[d][0]) | ((out[j + s] & masks[d][0]) << s);
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y = ((out[j] & masks[d][1]) >> s) | (out[j + s] & masks[d][1]);
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out[j + 0] = x;
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out[j + s] = y;
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}
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}
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}
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}
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