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Hi!
BZ #15522:
| strtod ("nan(N)") (and likewise for the other float types) exhibits wrong
| behavior such that for architectures defining
| HIGH_ORDER_BIT_IS_SET_FOR_SNAN, a sNaN is returned for N = 0, and for
| other architectures a sNaN is returned for positive integral N != 0.
Use the ieee754_* unions' ieee_nan member for easily setting a NaN's
mantissa without touching the quiet/signaling bit (or anything else), and
only if that new mantissa is unequal to zero (denoting infinity) use it
to overwrite the generic NaN's mantissa (which has been pre-set before
invoking SET_MANTISSA).
Tested for several MIPS multilibs, x86, x86_64, PowerPC -m64 (but a
PowerPC maintainer please confirm the
sysdeps/ieee754/ldbl-128ibm/ieee754.h change; I copied the ieee member
and changed it as done for other ldbl-*/ieee754.h's long double
structures/unions).
* stdlib/strtof_l.c (SET_MANTISSA): Rewrite.
* stdlib/strtod_l.c (SET_MANTISSA): Likewise.
* sysdeps/ieee754/ldbl-64-128/strtold_l.c (SET_MANTISSA): Likewise.
* sysdeps/ieee754/ldbl-96/strtold_l.c (SET_MANTISSA): Likewise.
* sysdeps/ieee754/ldbl-128/strtold_l.c (SET_MANTISSA): Likewise.
* sysdeps/ieee754/ldbl-128ibm/strtold_l.c (SET_MANTISSA): Likewise.
* sysdeps/ieee754/ldbl-128ibm/ieee754.h (ibm_extended_long_double):
Add ieee_nan member.
* stdlib/tst-strtod6.c (test): New function, renamed from do_test.
(do_test): New function.
diff --git stdlib/strtod_l.c stdlib/strtod_l.c
index 47247b5..5ed5a35 100644
--- stdlib/strtod_l.c
+++ stdlib/strtod_l.c
@@ -42,11 +42,10 @@ extern unsigned long long int ____strtoull_l_internal (const char *, char **,
# define SET_MANTISSA(flt, mant) \
do { union ieee754_double u; \
u.d = (flt); \
- if ((mant & 0xfffffffffffffULL) == 0) \
- mant = 0x8000000000000ULL; \
- u.ieee.mantissa0 = ((mant) >> 32) & 0xfffff; \
- u.ieee.mantissa1 = (mant) & 0xffffffff; \
- (flt) = u.d; \
+ u.ieee_nan.mantissa0 = (mant) >> 32; \
+ u.ieee_nan.mantissa1 = (mant); \
+ if ((u.ieee.mantissa0 | u.ieee.mantissa1) != 0) \
+ (flt) = u.d; \
} while (0)
#endif
/* End of configuration part. */
diff --git stdlib/strtof_l.c stdlib/strtof_l.c
index 6fb44bd..c4c1c1f 100644
--- stdlib/strtof_l.c
+++ stdlib/strtof_l.c
@@ -37,10 +37,9 @@ extern unsigned long long int ____strtoull_l_internal (const char *, char **,
#define SET_MANTISSA(flt, mant) \
do { union ieee754_float u; \
u.f = (flt); \
- if ((mant & 0x7fffff) == 0) \
- mant = 0x400000; \
- u.ieee.mantissa = (mant) & 0x7fffff; \
- (flt) = u.f; \
+ u.ieee_nan.mantissa = (mant); \
+ if (u.ieee.mantissa != 0) \
+ (flt) = u.f; \
} while (0)
#include "strtod_l.c"
diff --git stdlib/tst-strtod6.c stdlib/tst-strtod6.c
index 1d87266..15e79fd 100644
--- stdlib/tst-strtod6.c
+++ stdlib/tst-strtod6.c
@@ -4,12 +4,13 @@
#include <string.h>
static int
-do_test (void)
+test (const char str[])
{
- static const char str[] = "NaN(blabla)something";
char *endp;
int result = 0;
+ puts (str);
+
double d = strtod (str, &endp);
if (!isnan (d))
{
@@ -64,5 +65,24 @@ do_test (void)
return result;
}
+static int
+do_test (void)
+{
+ int result = 0;
+
+ result |= test ("NaN(blabla)something");
+ result |= test ("NaN(1234)something");
+ /* UINT32_MAX. */
+ result |= test ("NaN(4294967295)something");
+ /* UINT64_MAX. */
+ result |= test ("NaN(18446744073709551615)something");
+ /* The case of zero is special in that "something" has to be done to make the
+ mantissa different from zero, which would mean infinity instead of
+ NaN. */
+ result |= test ("NaN(0)something");
+
+ return result;
+}
+
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"
diff --git sysdeps/ieee754/ldbl-128/strtold_l.c sysdeps/ieee754/ldbl-128/strtold_l.c
index 8e0bc03..d3a1d1e 100644
--- sysdeps/ieee754/ldbl-128/strtold_l.c
+++ sysdeps/ieee754/ldbl-128/strtold_l.c
@@ -34,11 +34,13 @@
#define SET_MANTISSA(flt, mant) \
do { union ieee854_long_double u; \
u.d = (flt); \
- u.ieee.mantissa0 = 0x8000; \
- u.ieee.mantissa1 = 0; \
- u.ieee.mantissa2 = ((mant) >> 32); \
- u.ieee.mantissa3 = (mant) & 0xffffffff; \
- (flt) = u.d; \
+ u.ieee_nan.mantissa0 = 0; \
+ u.ieee_nan.mantissa1 = 0; \
+ u.ieee_nan.mantissa2 = (mant) >> 32; \
+ u.ieee_nan.mantissa3 = (mant); \
+ if ((u.ieee.mantissa0 | u.ieee.mantissa1 \
+ | u.ieee.mantissa2 | u.ieee.mantissa3) != 0) \
+ (flt) = u.d; \
} while (0)
#include <strtod_l.c>
diff --git sysdeps/ieee754/ldbl-128ibm/ieee754.h sysdeps/ieee754/ldbl-128ibm/ieee754.h
index e5644f5..9e94f53 100644
--- sysdeps/ieee754/ldbl-128ibm/ieee754.h
+++ sysdeps/ieee754/ldbl-128ibm/ieee754.h
@@ -199,6 +199,25 @@ union ibm_extended_long_double
unsigned int mantissa2:20;
unsigned int mantissa3:32;
} ieee;
+
+ /* This format makes it easier to see if a NaN is a signalling NaN. */
+ struct
+ { /* Big endian. There is no other. */
+
+ unsigned int negative:1;
+ unsigned int exponent:11;
+ unsigned int quiet_nan:1;
+ /* Together Mantissa0-3 comprise the mantissa. */
+ unsigned int mantissa0:19;
+ unsigned int mantissa1:32;
+
+ unsigned int negative2:1;
+ unsigned int exponent2:11;
+ /* There is an implied 1 here? */
+ /* Together these comprise the mantissa. */
+ unsigned int mantissa2:20;
+ unsigned int mantissa3:32;
+ } ieee_nan;
};
#define IBM_EXTENDED_LONG_DOUBLE_BIAS 0x3ff /* Added to exponent. */
diff --git sysdeps/ieee754/ldbl-128ibm/strtold_l.c sysdeps/ieee754/ldbl-128ibm/strtold_l.c
index 93415f0..04e3288 100644
--- sysdeps/ieee754/ldbl-128ibm/strtold_l.c
+++ sysdeps/ieee754/ldbl-128ibm/strtold_l.c
@@ -44,11 +44,10 @@ libc_hidden_proto (STRTOF)
# define SET_MANTISSA(flt, mant) \
do { union ibm_extended_long_double u; \
u.d = (flt); \
- if ((mant & 0xfffffffffffffULL) == 0) \
- mant = 0x8000000000000ULL; \
- u.ieee.mantissa0 = ((mant) >> 32) & 0xfffff; \
- u.ieee.mantissa1 = (mant) & 0xffffffff; \
- (flt) = u.d; \
+ u.ieee_nan.mantissa0 = (mant) >> 32; \
+ u.ieee_nan.mantissa1 = (mant); \
+ if ((u.ieee.mantissa0 | u.ieee.mantissa1) != 0) \
+ (flt) = u.d; \
} while (0)
#include <strtod_l.c>
diff --git sysdeps/ieee754/ldbl-64-128/strtold_l.c sysdeps/ieee754/ldbl-64-128/strtold_l.c
index 8182b2b..e9b33f2 100644
--- sysdeps/ieee754/ldbl-64-128/strtold_l.c
+++ sysdeps/ieee754/ldbl-64-128/strtold_l.c
@@ -44,11 +44,13 @@ libc_hidden_proto (STRTOF)
#define SET_MANTISSA(flt, mant) \
do { union ieee854_long_double u; \
u.d = (flt); \
- u.ieee.mantissa0 = 0x8000; \
- u.ieee.mantissa1 = 0; \
- u.ieee.mantissa2 = ((mant) >> 32); \
- u.ieee.mantissa3 = (mant) & 0xffffffff; \
- (flt) = u.d; \
+ u.ieee_nan.mantissa0 = 0; \
+ u.ieee_nan.mantissa1 = 0; \
+ u.ieee_nan.mantissa2 = (mant) >> 32; \
+ u.ieee_nan.mantissa3 = (mant); \
+ if ((u.ieee.mantissa0 | u.ieee.mantissa1 \
+ | u.ieee.mantissa2 | u.ieee.mantissa3) != 0) \
+ (flt) = u.d; \
} while (0)
#include <strtod_l.c>
diff --git sysdeps/ieee754/ldbl-96/strtold_l.c sysdeps/ieee754/ldbl-96/strtold_l.c
index ded84f3..dccf98c 100644
--- sysdeps/ieee754/ldbl-96/strtold_l.c
+++ sysdeps/ieee754/ldbl-96/strtold_l.c
@@ -34,11 +34,10 @@
#define SET_MANTISSA(flt, mant) \
do { union ieee854_long_double u; \
u.d = (flt); \
- if ((mant & 0x7fffffffffffffffULL) == 0) \
- mant = 0x4000000000000000ULL; \
- u.ieee.mantissa0 = (((mant) >> 32) & 0x7fffffff) | 0x80000000; \
- u.ieee.mantissa1 = (mant) & 0xffffffff; \
- (flt) = u.d; \
+ u.ieee_nan.mantissa0 = (mant) >> 32; \
+ u.ieee_nan.mantissa1 = (mant); \
+ if ((u.ieee.mantissa0 | u.ieee.mantissa1) != 0) \
+ (flt) = u.d; \
} while (0)
#include <stdlib/strtod_l.c>
I used the following hack for manually verifying the expected bit
patterns for the resulting NaNs' mantissas; not proposing to commit. ;-)
diff --git stdlib/tst-strtod6.c stdlib/tst-strtod6.c
index 15e79fd..05532b6 100644
--- stdlib/tst-strtod6.c
+++ stdlib/tst-strtod6.c
@@ -2,6 +2,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <stdint.h>
static int
test (const char str[])
@@ -12,6 +13,9 @@ test (const char str[])
puts (str);
double d = strtod (str, &endp);
+ printf("%08x ", ((uint32_t *) &d)[0]);
+ printf("%08x ", ((uint32_t *) &d)[1]);
+ puts("");
if (!isnan (d))
{
puts ("strtod did not return NAN");
@@ -29,6 +33,8 @@ test (const char str[])
}
float f = strtof (str, &endp);
+ printf("%08x ", ((uint32_t *) &f)[0]);
+ puts("");
if (!isnanf (f))
{
puts ("strtof did not return NAN");
@@ -46,6 +52,11 @@ test (const char str[])
}
long double ld = strtold (str, &endp);
+ printf("%08x ", ((uint32_t *) &ld)[0]);
+ printf("%08x ", ((uint32_t *) &ld)[1]);
+ printf("%08x ", ((uint32_t *) &ld)[2]);
+ printf("%08x ", ((uint32_t *) &ld)[3]);
+ puts("");
if (!isnan (ld))
{
puts ("strtold did not return NAN");
GrÃÃe,
Thomas
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