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grasshoper: mgm: small speedup #153

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43 changes: 21 additions & 22 deletions gost_grasshopper_cipher.c
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Original file line number Diff line number Diff line change
Expand Up @@ -599,32 +599,29 @@ static void gf128_mul_uint64(uint64_t *result, uint64_t *arg1, uint64_t *arg2)
{
int i = 0, n = 0;
uint64_t t, s0, s1;
uint64_t x[2], y[2], z[2];

BUF_reverse((unsigned char *)x, (unsigned char *)arg1, 16);
BUF_reverse((unsigned char *)y, (unsigned char *)arg2, 16);
uint64_t z[2];

#ifdef L_ENDIAN
s0 = x[0];
s1 = x[1];
s0 = bswap_64(arg1[1]);
s1 = bswap_64(arg1[0]);
#else
s0 = bswap_64(x[0]);
s1 = bswap_64(x[1]);
s0 = arg1[1];
s1 = arg1[0];
#endif

memset(z, 0, sizeof(uint64_t) * 2);

/* lower half */
#ifdef L_ENDIAN
t = y[0];
t = bswap_64(arg2[1]);
#else
t = bswap_64(y[0]);
t = arg2[1];
#endif

for (i = 0; i < 64; i++) {
if (t & 0x1) {
z[0] ^= s0;
z[1] ^= s1;
z[1] ^= s0;
z[0] ^= s1;
}
t >>= 1;
n = s1 >> 63;
Expand All @@ -637,15 +634,15 @@ static void gf128_mul_uint64(uint64_t *result, uint64_t *arg1, uint64_t *arg2)

/* upper half */
#ifdef L_ENDIAN
t = y[1];
t = bswap_64(arg2[0]);
#else
t = bswap_64(y[1]);
t = arg2[0];
#endif

for (i = 0; i < 63; i++) {
if (t & 0x1) {
z[0] ^= s0;
z[1] ^= s1;
z[1] ^= s0;
z[0] ^= s1;
}
t >>= 1;
n = s1 >> 63;
Expand All @@ -657,14 +654,16 @@ static void gf128_mul_uint64(uint64_t *result, uint64_t *arg1, uint64_t *arg2)
}

if (t & 0x1) {
z[0] ^= s0;
z[1] ^= s1;
z[1] ^= s0;
z[0] ^= s1;
}
#ifndef L_ENDIAN
z[0] = bswap_64(z[0]);
z[1] = bswap_64(z[1]);
#ifdef L_ENDIAN
result[0] = bswap_64(z[0]);
result[1] = bswap_64(z[1]);
#else
result[0] = z[0];
result[1] = z[1];
#endif
BUF_reverse((unsigned char *)result, (unsigned char *)z, 16);
}

static void hexdump(FILE *f, const char *title, const unsigned char *s, int l)
Expand Down