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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
parent19fcedd5fcaab4355adf62350224ce53797f0f5a (diff)
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Make strtod respect the rounding mode (bug 14518).
Diffstat (limited to 'stdlib')
-rw-r--r--stdlib/Makefile1
-rw-r--r--stdlib/strtod_l.c70
-rw-r--r--stdlib/tst-strtod-round.c133
3 files changed, 152 insertions, 52 deletions
diff --git a/stdlib/Makefile b/stdlib/Makefile
index dfc5eaf97b..c730b47433 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -150,3 +150,4 @@ else
link-libm = $(common-objpfx)math/libm.a
endif
$(objpfx)bug-getcontext: $(link-libm)
+$(objpfx)tst-strtod-round: $(link-libm)
diff --git a/stdlib/strtod_l.c b/stdlib/strtod_l.c
index ccd117a9f1..95f13e40a2 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
diff --git a/stdlib/tst-strtod-round.c b/stdlib/tst-strtod-round.c
index c6ad126873..76385a94d3 100644
--- a/stdlib/tst-strtod-round.c
+++ b/stdlib/tst-strtod-round.c
@@ -17,6 +17,7 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
+#include <fenv.h>
#include <float.h>
#include <math.h>
#include <stdbool.h>
@@ -24,21 +25,32 @@
#include <stdlib.h>
#include <string.h>
-struct test {
- const char *s;
+struct test_results {
float f;
double d;
- bool ld_ok;
long double ld;
};
+struct test {
+ const char *s;
+ bool ld_ok;
+ struct test_results rd, rn, rz, ru;
+};
+
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
# define TEST(s, fd, fn, fz, fu, dd, dn, dz, du, ld53d, ld53n, ld53z, ld53u, \
ld64id, ld64in, ld64iz, ld64iu, \
ld64md, ld64mn, ld64mz, ld64mu, \
ld106exact, ld106d, ld106n, ld106z, ld106u, \
ld113d, ld113n, ld113z, ld113u) \
- { s, fn, dn, true, ld53n }
+ { \
+ s, \
+ true, \
+ { fd, dd, ld53d }, \
+ { fn, dn, ld53n }, \
+ { fz, dz, ld53z }, \
+ { fu, du, ld53u } \
+ }
#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 && LDBL_MIN_EXP == -16381
/* This is for the Intel extended float format. */
# define TEST(s, fd, fn, fz, fu, dd, dn, dz, du, ld53d, ld53n, ld53z, ld53u, \
@@ -46,7 +58,14 @@ struct test {
ld64md, ld64mn, ld64mz, ld64mu, \
ld106exact, ld106d, ld106n, ld106z, ld106u, \
ld113d, ld113n, ld113z, ld113u) \
- { s, fn, dn, true, ld64in }
+ { \
+ s, \
+ true, \
+ { fd, dd, ld64id }, \
+ { fn, dn, ld64in }, \
+ { fz, dz, ld64iz }, \
+ { fu, du, ld64iu } \
+ }
#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 && LDBL_MIN_EXP == -16382
/* This is for the Motorola extended float format. */
# define TEST(s, fd, fn, fz, fu, dd, dn, dz, du, ld53d, ld53n, ld53z, ld53u, \
@@ -54,21 +73,42 @@ struct test {
ld64md, ld64mn, ld64mz, ld64mu, \
ld106exact, ld106d, ld106n, ld106z, ld106u, \
ld113d, ld113n, ld113z, ld113u) \
- { s, fn, dn, true, ld64mn }
+ { \
+ s, \
+ true, \
+ { fd, dd, ld64md }, \
+ { fn, dn, ld64mn }, \
+ { fz, dz, ld64mz }, \
+ { fu, du, ld64mu } \
+ }
#elif LDBL_MANT_DIG == 106 && LDBL_MAX_EXP == 1024
# define TEST(s, fd, fn, fz, fu, dd, dn, dz, du, ld53d, ld53n, ld53z, ld53u, \
ld64id, ld64in, ld64iz, ld64iu, \
ld64md, ld64mn, ld64mz, ld64mu, \
ld106exact, ld106d, ld106n, ld106z, ld106u, \
ld113d, ld113n, ld113z, ld113u) \
- { s, fn, dn, ld106exact, ld106n }
+ { \
+ s, \
+ ld106exact, \
+ { fd, dd, ld106d }, \
+ { fn, dn, ld106n }, \
+ { fz, dz, ld106z }, \
+ { fu, du, ld106u } \
+ }
#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
# define TEST(s, fd, fn, fz, fu, dd, dn, dz, du, ld53d, ld53n, ld53z, ld53u, \
ld64id, ld64in, ld64iz, ld64iu, \
ld64md, ld64mn, ld64mz, ld64mu, \
ld106exact, ld106d, ld106n, ld106z, ld106u, \
ld113d, ld113n, ld113z, ld113u) \
- { s, fn, dn, true, ld113n }
+ { \
+ s, \
+ true, \
+ { fd, dd, ld113d }, \
+ { fn, dn, ld113n }, \
+ { fz, dz, ld113z }, \
+ { fu, du, ld113u } \
+ }
#else
# error "unknown long double format"
#endif
@@ -6819,38 +6859,73 @@ static const struct test tests[] = {
};
static int
+test_in_one_mode (const char *s, const struct test_results *expected,
+ bool ld_ok, const char *mode_name)
+{
+ int result = 0;
+ float f = strtof (s, NULL);
+ double d = strtod (s, NULL);
+ long double ld = strtold (s, NULL);
+ if (f != expected->f
+ || copysignf (1.0f, f) != copysignf (1.0f, expected->f))
+ {
+ printf ("strtof (%s) returned %a not %a (%s)\n", s, f,
+ expected->f, mode_name);
+ result = 1;
+ }
+ if (d != expected->d
+ || copysign (1.0, d) != copysign (1.0, expected->d))
+ {
+ printf ("strtod (%s) returned %a not %a (%s)\n", s, d,
+ expected->d, mode_name);
+ result = 1;
+ }
+ if (ld != expected->ld
+ || copysignl (1.0L, ld) != copysignl (1.0L, expected->ld))
+ {
+ printf ("strtold (%s) returned %La not %La (%s)\n", s, ld,
+ expected->ld, mode_name);
+ if (ld_ok)
+ result = 1;
+ else
+ printf ("ignoring this inexact long double result\n");
+ }
+ return result;
+}
+
+static int
do_test (void)
{
+ int save_round_mode = fegetround ();
int result = 0;
for (size_t i = 0; i < sizeof (tests) / sizeof (tests[0]); i++)
{
- float f = strtof (tests[i].s, NULL);
- double d = strtod (tests[i].s, NULL);
- long double ld = strtold (tests[i].s, NULL);
- if (f != tests[i].f
- || copysignf (1.0f, f) != copysignf (1.0f, tests[i].f))
+ result |= test_in_one_mode (tests[i].s, &tests[i].rn, tests[i].ld_ok,
+ "default rounding mode");
+#ifdef FE_DOWNWARD
+ if (!fesetround (FE_DOWNWARD))
{
- printf ("strtof (%s) returned %a not %a\n", tests[i].s, f,
- tests[i].f);
- result = 1;
+ result |= test_in_one_mode (tests[i].s, &tests[i].rd, tests[i].ld_ok,
+ "FE_DOWNWARD");
+ fesetround (save_round_mode);
}
- if (d != tests[i].d
- || copysign (1.0, d) != copysign (1.0, tests[i].d))
+#endif
+#ifdef FE_TOWARDZERO
+ if (!fesetround (FE_TOWARDZERO))
{
- printf ("strtod (%s) returned %a not %a\n", tests[i].s, d,
- tests[i].d);
- result = 1;
+ result |= test_in_one_mode (tests[i].s, &tests[i].rz, tests[i].ld_ok,
+ "FE_TOWARDZERO");
+ fesetround (save_round_mode);
}
- if (ld != tests[i].ld
- || copysignl (1.0L, ld) != copysignl (1.0L, tests[i].ld))
+#endif
+#ifdef FE_UPWARD
+ if (!fesetround (FE_UPWARD))
{
- printf ("strtold (%s) returned %La not %La\n", tests[i].s, ld,
- tests[i].ld);
- if (tests[i].ld_ok)
- result = 1;
- else
- printf ("ignoring this inexact long double result\n");
+ result |= test_in_one_mode (tests[i].s, &tests[i].ru, tests[i].ld_ok,
+ "FE_UPWARD");
+ fesetround (save_round_mode);
}
+#endif
}
return result;
}