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Fix #1991 asm multiply again

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Tweak temp variables and constraints. Was working before if not inlined
but newer gcc tends to inline it.
This commit is contained in:
Howard Chu 2017-06-08 20:40:51 +01:00
parent e3da0ca828
commit 1dd524151d
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GPG key ID: FD2A70B44AB11BA7
1 changed files with 13 additions and 16 deletions
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29
src/crypto/slow-hash.c
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@ -979,34 +979,31 @@ STATIC void cn_mul128(const uint64_t *a, const uint64_t *b, uint64_t *r)
r[1] = lo;
}
#else /* ARM32 */
/* Can work as inline, but actually runs slower. Keep it separate */
#define mul(a, b, c) cn_mul128((const uint32_t *)a, (const uint32_t *)b, (uint32_t *)c)
void cn_mul128(const uint32_t *aa, const uint32_t *bb, uint32_t *r)
STATIC void cn_mul128(const uint32_t *aa, const uint32_t *bb, uint32_t *r)
{
uint32_t t0, t1;
uint32_t t0, t1, t2=0, t3=0;
__asm__ __volatile__(
"umull %[t0], %[t1], %[a], %[b]\n\t"
"str %[t0], [%[r], #8]\n\t"
"str %[t0], %[ll]\n\t"
// accumulating with 0 can never overflow/carry
"mov %[t0], #0\n\t"
"eor %[t0], %[t0]\n\t"
"umlal %[t1], %[t0], %[a], %[B]\n\t"
"mov %[a], #0\n\t"
"umlal %[t1], %[a], %[A], %[b]\n\t"
"str %[t1], [%[r], #12]\n\t"
"umlal %[t1], %[t2], %[A], %[b]\n\t"
"str %[t1], %[lh]\n\t"
"mov %[b], #0\n\t"
"umlal %[t0], %[b], %[A], %[B]\n\t"
"umlal %[t0], %[t3], %[A], %[B]\n\t"
// final add may have a carry
"adds %[t0], %[t0], %[a]\n\t"
"adc %[t1], %[b], #0\n\t"
"adds %[t0], %[t0], %[t2]\n\t"
"adc %[t1], %[t3], #0\n\t"
"str %[t0], [%[r]]\n\t"
"str %[t1], [%[r], #4]\n\t"
: [t0]"=&r"(t0), [t1]"=&r"(t1), "=m"(r[0]), "=m"(r[1]), "=m"(r[2]), "=m"(r[3])
: [A]"r"(aa[1]), [a]"r"(aa[0]), [B]"r"(bb[1]), [b]"r"(bb[0]), [r]"r"(r)
"str %[t0], %[hl]\n\t"
"str %[t1], %[hh]\n\t"
: [t0]"=&r"(t0), [t1]"=&r"(t1), [t2]"+r"(t2), [t3]"+r"(t3), [hl]"=m"(r[0]), [hh]"=m"(r[1]), [ll]"=m"(r[2]), [lh]"=m"(r[3])
: [A]"r"(aa[1]), [a]"r"(aa[0]), [B]"r"(bb[1]), [b]"r"(bb[0])
: "cc");
}
#endif /* !aarch64 */