size_t s;
{
mp_limb_t msd = b_ptr[b_len - 1]; /* = b[n-1], > 0 */
- s = 31;
- if (msd >= 0x10000)
- {
- msd = msd >> 16;
- s -= 16;
- }
- if (msd >= 0x100)
- {
- msd = msd >> 8;
- s -= 8;
- }
- if (msd >= 0x10)
- {
- msd = msd >> 4;
- s -= 4;
- }
- if (msd >= 0x4)
+ /* Determine s = GMP_LIMB_BITS - integer_length (msd).
+ Code copied from gnulib's integer_length.c. */
+# if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
+ s = __builtin_clz (msd);
+# else
+# if defined DBL_EXPBIT0_WORD && defined DBL_EXPBIT0_BIT
+ if (GMP_LIMB_BITS <= DBL_MANT_BIT)
{
- msd = msd >> 2;
- s -= 2;
+ /* Use 'double' operations.
+ Assumes an IEEE 754 'double' implementation. */
+# define DBL_EXP_MASK ((DBL_MAX_EXP - DBL_MIN_EXP) | 7)
+# define DBL_EXP_BIAS (DBL_EXP_MASK / 2 - 1)
+# define NWORDS \
+ ((sizeof (double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
+ union { double value; unsigned int word[NWORDS]; } m;
+
+ /* Use a single integer to floating-point conversion. */
+ m.value = msd;
+
+ s = GMP_LIMB_BITS
+ - (((m.word[DBL_EXPBIT0_WORD] >> DBL_EXPBIT0_BIT) & DBL_EXP_MASK)
+ - DBL_EXP_BIAS);
}
- if (msd >= 0x2)
+ else
+# undef NWORDS
+# endif
{
- msd = msd >> 1;
- s -= 1;
+ s = 31;
+ if (msd >= 0x10000)
+ {
+ msd = msd >> 16;
+ s -= 16;
+ }
+ if (msd >= 0x100)
+ {
+ msd = msd >> 8;
+ s -= 8;
+ }
+ if (msd >= 0x10)
+ {
+ msd = msd >> 4;
+ s -= 4;
+ }
+ if (msd >= 0x4)
+ {
+ msd = msd >> 2;
+ s -= 2;
+ }
+ if (msd >= 0x2)
+ {
+ msd = msd >> 1;
+ s -= 1;
+ }
}
+# endif
}
/* 0 <= s < GMP_LIMB_BITS.
Copy b, shifting it left by s bits. */
y = frexpl (x, &exp);
if (!(y >= 0.0L && y < 1.0L))
abort ();
- /* x = 2^exp * y = 2^(exp - LDBL_MANT_BIT) * (y * LDBL_MANT_BIT), and the
+ /* x = 2^exp * y = 2^(exp - LDBL_MANT_BIT) * (y * 2^LDBL_MANT_BIT), and the
latter is an integer. */
- /* Convert the mantissa (y * LDBL_MANT_BIT) to a sequence of limbs.
+ /* Convert the mantissa (y * 2^LDBL_MANT_BIT) to a sequence of limbs.
I'm not sure whether it's safe to cast a 'long double' value between
2^31 and 2^32 to 'unsigned int', therefore play safe and cast only
'long double' values between 0 and 2^16 (to 'unsigned int' or 'int',
abort ();
m.limbs[--i] = (hi << (GMP_LIMB_BITS / 2)) | lo;
}
-#if 0 /* On FreeBSD 6.1/x86, 'long double' numbers sometimes have excess
- precision. */
+# if 0 /* On FreeBSD 6.1/x86, 'long double' numbers sometimes have excess
+ precision. */
if (!(y == 0.0L))
abort ();
-#endif
+# endif
/* Normalise. */
while (m.nlimbs > 0 && m.limbs[m.nlimbs - 1] == 0)
m.nlimbs--;
y = frexp (x, &exp);
if (!(y >= 0.0 && y < 1.0))
abort ();
- /* x = 2^exp * y = 2^(exp - DBL_MANT_BIT) * (y * DBL_MANT_BIT), and the
+ /* x = 2^exp * y = 2^(exp - DBL_MANT_BIT) * (y * 2^DBL_MANT_BIT), and the
latter is an integer. */
- /* Convert the mantissa (y * DBL_MANT_BIT) to a sequence of limbs.
+ /* Convert the mantissa (y * 2^DBL_MANT_BIT) to a sequence of limbs.
I'm not sure whether it's safe to cast a 'double' value between
2^31 and 2^32 to 'unsigned int', therefore play safe and cast only
'double' values between 0 and 2^16 (to 'unsigned int' or 'int',
return NULL;
#define CLEANUP() \
- free (d.dir); \
- if (a.arg) \
+ if (d.dir != d.direct_alloc_dir) \
+ free (d.dir); \
+ if (a.arg != a.direct_alloc_arg) \
free (a.arg);
if (PRINTF_FETCHARGS (args, &a) < 0)