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authorJoseph Myers <joseph@codesourcery.com>2012-09-12 23:36:19 +0000
committerJoseph Myers <joseph@codesourcery.com>2012-09-12 23:36:19 +0000
commit6c9b0f68267cf365d060d4e51e7cb8f61498b875 (patch)
tree7527c31f9593972fa3781f570b1712ba79d4a556 /stdlib/strtod_l.c
parent19fcedd5fcaab4355adf62350224ce53797f0f5a (diff)
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Make strtod respect the rounding mode (bug 14518).
Diffstat (limited to 'stdlib/strtod_l.c')
-rw-r--r--stdlib/strtod_l.c70
1 files changed, 47 insertions, 23 deletions
diff --git a/stdlib/strtod_l.c b/stdlib/strtod_l.c
index ccd117a..95f13e4 100644
--- a/stdlib/strtod_l.c
+++ b/stdlib/strtod_l.c
@@ -61,6 +61,7 @@ extern unsigned long long int ____strtoull_l_internal (const char *, char **,
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
+#include <rounding-mode.h>
/* The gmp headers need some configuration frobs. */
#define HAVE_ALLOCA 1
@@ -126,6 +127,8 @@ extern unsigned long long int ____strtoull_l_internal (const char *, char **,
#define MIN_EXP PASTE(FLT,_MIN_EXP)
#define MAX_10_EXP PASTE(FLT,_MAX_10_EXP)
#define MIN_10_EXP PASTE(FLT,_MIN_10_EXP)
+#define MAX_VALUE PASTE(FLT,_MAX)
+#define MIN_VALUE PASTE(FLT,_MIN)
/* Extra macros required to get FLT expanded before the pasting. */
#define PASTE(a,b) PASTE1(a,b)
@@ -172,6 +175,34 @@ extern const mp_limb_t _tens_in_limb[MAX_DIG_PER_LIMB + 1];
memcpy (dst, src, (dst##size = src##size) * sizeof (mp_limb_t))
+/* Set errno and return an overflowing value with sign specified by
+ NEGATIVE. */
+static FLOAT
+overflow_value (int negative)
+{
+ __set_errno (ERANGE);
+#if FLT_EVAL_METHOD != 0
+ volatile
+#endif
+ FLOAT result = (negative ? -MAX_VALUE : MAX_VALUE) * MAX_VALUE;
+ return result;
+}
+
+
+/* Set errno and return an underflowing value with sign specified by
+ NEGATIVE. */
+static FLOAT
+underflow_value (int negative)
+{
+ __set_errno (ERANGE);
+#if FLT_EVAL_METHOD != 0
+ volatile
+#endif
+ FLOAT result = (negative ? -MIN_VALUE : MIN_VALUE) * MIN_VALUE;
+ return result;
+}
+
+
/* Return a floating point number of the needed type according to the given
multi-precision number after possible rounding. */
static FLOAT
@@ -181,10 +212,7 @@ round_and_return (mp_limb_t *retval, intmax_t exponent, int negative,
if (exponent < MIN_EXP - 1)
{
if (exponent < MIN_EXP - 1 - MANT_DIG)
- {
- __set_errno (ERANGE);
- return negative ? -0.0 : 0.0;
- }
+ return underflow_value (negative);
mp_size_t shift = MIN_EXP - 1 - exponent;
@@ -237,9 +265,14 @@ round_and_return (mp_limb_t *retval, intmax_t exponent, int negative,
if (exponent > MAX_EXP)
goto overflow;
- if ((round_limb & (((mp_limb_t) 1) << round_bit)) != 0
- && (more_bits || (retval[0] & 1) != 0
- || (round_limb & ((((mp_limb_t) 1) << round_bit) - 1)) != 0))
+ int mode = get_rounding_mode ();
+
+ if (round_away (negative,
+ (retval[0] & 1) != 0,
+ (round_limb & (((mp_limb_t) 1) << round_bit)) != 0,
+ (more_bits
+ || (round_limb & ((((mp_limb_t) 1) << round_bit) - 1)) != 0),
+ mode))
{
mp_limb_t cy = __mpn_add_1 (retval, retval, RETURN_LIMB_SIZE, 1);
@@ -263,7 +296,7 @@ round_and_return (mp_limb_t *retval, intmax_t exponent, int negative,
if (exponent > MAX_EXP)
overflow:
- return negative ? -FLOAT_HUGE_VAL : FLOAT_HUGE_VAL;
+ return overflow_value (negative);
return MPN2FLOAT (retval, exponent, negative);
}
@@ -914,9 +947,9 @@ ____STRTOF_INTERNAL (nptr, endptr, group, loc)
else
{
/* Overflow or underflow. */
- __set_errno (ERANGE);
- result = (exp_negative ? (negative ? -0.0 : 0.0) :
- negative ? -FLOAT_HUGE_VAL : FLOAT_HUGE_VAL);
+ result = (exp_negative
+ ? underflow_value (negative)
+ : overflow_value (negative));
}
/* Accept all following digits as part of the exponent. */
@@ -1112,16 +1145,10 @@ ____STRTOF_INTERNAL (nptr, endptr, group, loc)
}
if (__builtin_expect (exponent > MAX_10_EXP + 1 - (intmax_t) int_no, 0))
- {
- __set_errno (ERANGE);
- return negative ? -FLOAT_HUGE_VAL : FLOAT_HUGE_VAL;
- }
+ return overflow_value (negative);
if (__builtin_expect (exponent < MIN_10_EXP - (DIG + 1), 0))
- {
- __set_errno (ERANGE);
- return negative ? -0.0 : 0.0;
- }
+ return underflow_value (negative);
if (int_no > 0)
{
@@ -1182,10 +1209,7 @@ ____STRTOF_INTERNAL (nptr, endptr, group, loc)
/* Now we know the exponent of the number in base two.
Check it against the maximum possible exponent. */
if (__builtin_expect (bits > MAX_EXP, 0))
- {
- __set_errno (ERANGE);
- return negative ? -FLOAT_HUGE_VAL : FLOAT_HUGE_VAL;
- }
+ return overflow_value (negative);
/* We have already the first BITS bits of the result. Together with
the information whether more non-zero bits follow this is enough