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FFI: Split up 64 bit x^k helper into signed/unsigned.

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This commit is contained in:
Mike Pall
2011-01-28 02:15:30 +01:00
parent cd9b8f90e2
commit 07d8a53b39
4 changed files with 34 additions and 20 deletions
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43
src/lj_carith.c
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@@ -184,7 +184,12 @@ static int carith_int64(lua_State *L, CTState *cts, CDArith *ca, MMS mm)
else
*up = u0 % u1;
break;
case MM_pow: *up = lj_carith_powi64(u0, u1, (id == CTID_UINT64)); break;
case MM_pow:
if (id == CTID_INT64)
*up = (uint64_t)lj_carith_powi64((int64_t)u0, (int64_t)u1);
else
*up = lj_carith_powu64(u0, u1);
break;
case MM_unm: *up = (uint64_t)-(int64_t)u0; break;
default: lua_assert(0); break;
}
@@ -225,24 +230,12 @@ int lj_carith_op(lua_State *L, MMS mm)
/* -- 64 bit integer arithmetic helpers ----------------------------------- */
/* 64 bit integer x^k. */
uint64_t lj_carith_powi64(uint64_t x, uint64_t k, int isunsigned)
/* Unsigned 64 bit x^k. */
uint64_t lj_carith_powu64(uint64_t x, uint64_t k)
{
uint64_t y = 0;
uint64_t y;
if (k == 0)
return 1;
if (!isunsigned) {
if ((int64_t)k < 0) {
if (x == 0)
return U64x(7fffffff,ffffffff);
else if (x == 1)
return 1;
else if ((int64_t)x == -1)
return (k & 1) ? -1 : 1;
else
return 0;
}
}
for (; (k & 1) == 0; k >>= 1) x *= x;
y = x;
if ((k >>= 1) != 0) {
@@ -257,4 +250,22 @@ uint64_t lj_carith_powi64(uint64_t x, uint64_t k, int isunsigned)
return y;
}
/* Signed 64 bit x^k. */
int64_t lj_carith_powi64(int64_t x, int64_t k)
{
if (k == 0)
return 1;
if (k < 0) {
if (x == 0)
return U64x(7fffffff,ffffffff);
else if (x == 1)
return 1;
else if (x == -1)
return (k & 1) ? -1 : 1;
else
return 0;
}
return (int64_t)lj_carith_powu64((uint64_t)x, (uint64_t)k);
}
#endif