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[PATCH v2] Fix formatting of denormal IBM long double numbers
- From: Andreas Schwab <schwab at linux-m68k dot org>
- To: libc-alpha at sourceware dot org
- Date: Tue, 24 Apr 2012 19:23:31 +0200
- Subject: [PATCH v2] Fix formatting of denormal IBM long double numbers
- References: <m2y5pmw5rb.fsf@igel.home>
[BZ #13941]
* sysdeps/ieee754/ldbl-128ibm/ldbl2mpn.c
(__mpn_extract_long_double): Use DBL_MIN_EXP instead of
LDBL_MIN_EXP.
* stdio-common/Makefile (tests): Add tst-sprintf3.
* stdio-common/tst-sprintf3.c: New file.
diff --git a/stdio-common/Makefile b/stdio-common/Makefile
index 8cf6335..7519bc1 100644
--- a/stdio-common/Makefile
+++ b/stdio-common/Makefile
@@ -56,7 +56,7 @@ tests := tstscanf test_rdwr test-popen tstgetln test-fseek \
tst-fwrite bug16 bug17 tst-swscanf tst-sprintf2 bug18 bug18a \
bug19 bug19a tst-popen2 scanf13 scanf14 scanf15 bug20 bug21 bug22 \
scanf16 scanf17 tst-setvbuf1 tst-grouping bug23 bug24 \
- bug-vfprintf-nargs tst-long-dbl-fphex tst-fphex-wide
+ bug-vfprintf-nargs tst-long-dbl-fphex tst-fphex-wide tst-sprintf3
test-srcs = tst-unbputc tst-printf
diff --git a/stdio-common/tst-sprintf3.c b/stdio-common/tst-sprintf3.c
new file mode 100644
index 0000000..4be24b0
--- /dev/null
+++ b/stdio-common/tst-sprintf3.c
@@ -0,0 +1,71 @@
+#include <float.h>
+#include <math.h>
+#include <stdio.h>
+#include <string.h>
+
+int
+main (void)
+{
+#if LDBL_MANT_DIG >= 106
+ volatile union { long double l; long long x[2]; } u, v;
+ char buf[64];
+#endif
+ int result = 0;
+
+#if LDBL_MANT_DIG == 106 || LDBL_MANT_DIG == 113
+# define COMPARE_LDBL(u, v) \
+ ((u).l == (v).l && (u).x[0] == (v).x[0] && (u).x[1] == (v).x[1])
+#else
+# define COMPARE_LDBL(u, v) ((u).l == (v).l)
+#endif
+
+#define TEST(val) \
+ do \
+ { \
+ u.l = (val); \
+ snprintf (buf, sizeof buf, "%.30LgL", u.l); \
+ if (strcmp (buf, #val) != 0) \
+ { \
+ printf ("Error on line %d: %s != %s\n", __LINE__, buf, #val); \
+ result = 1; \
+ } \
+ if (sscanf (#val, "%Lg", &v.l) != 1 || !COMPARE_LDBL (u, v)) \
+ { \
+ printf ("Error sscanf on line %d: %.30Lg != %.30Lg\n", __LINE__, \
+ u.l, v.l); \
+ result = 1; \
+ } \
+ /* printf ("%s %Lg %016Lx %016Lx\n", #val, u.l, u.x[0], u.x[1]); */ \
+ } \
+ while (0)
+
+#if LDBL_MANT_DIG >= 106
+# if LDBL_MANT_DIG == 106
+ TEST (2.22507385850719347803989925739e-308L);
+ TEST (2.22507385850719397210554509863e-308L);
+ TEST (2.22507385850720088902458687609e-308L);
+# endif
+ TEST (2.22507385850720138309023271733e-308L);
+ TEST (2.22507385850720187715587855858e-308L);
+ TEST (2.2250738585074419930597574044e-308L);
+ TEST (4.45014771701440227211481959342e-308L);
+ TEST (4.45014771701440276618046543466e-308L);
+ TEST (4.45014771701440375431175711716e-308L);
+ TEST (4.45014771701440474244304879965e-308L);
+ TEST (7.12023634722304600689881138745e-307L);
+ TEST (1.13923781555569064960474854133e-305L);
+ TEST (1.13777777777777776389998996996L);
+ TEST (1.13777777777777765287768750745L);
+ TEST (20988295479420645138.2044444444L);
+ TEST (20988295479420643090.2044444444L);
+ TEST (2.14668699894294423266045294316e-292L);
+# if LDBL_MANT_DIG == 106
+ TEST (-2.35993711055432139266626434123e-292L);
+ TEST (6.26323524637968345414769634658e-302L);
+ TEST (1.49327164802066885331814201989e-308L);
+ TEST (3.71834550652787023640837473722e-308L);
+ TEST (9.51896449671134907001349268087e-306L);
+# endif
+#endif
+ return result;
+}
diff --git a/sysdeps/ieee754/ldbl-128ibm/ldbl2mpn.c b/sysdeps/ieee754/ldbl-128ibm/ldbl2mpn.c
index 3162bbd..e65366d 100644
--- a/sysdeps/ieee754/ldbl-128ibm/ldbl2mpn.c
+++ b/sysdeps/ieee754/ldbl-128ibm/ldbl2mpn.c
@@ -1,5 +1,4 @@
-/* Copyright (C) 1995,1996,1997,1998,1999,2002,2003,2006
- Free Software Foundation, Inc.
+/* Copyright (C) 1995-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
@@ -104,7 +103,10 @@ __mpn_extract_long_double (mp_ptr res_ptr, mp_size_t size,
else
{
/* It is a denormal number, meaning it has no implicit leading
- one bit, and its exponent is in fact the format minimum. */
+ one bit, and its exponent is in fact the format minimum. We
+ use DBL_MIN_EXP instead of LDBL_MIN_EXP below because the
+ latter describes the properties of the both parts together,
+ but the exponent is computed from the high part only. */
int cnt;
#if N == 2
@@ -115,7 +117,7 @@ __mpn_extract_long_double (mp_ptr res_ptr, mp_size_t size,
res_ptr[N - 1] = res_ptr[N - 1] << cnt
| (res_ptr[0] >> (BITS_PER_MP_LIMB - cnt));
res_ptr[0] <<= cnt;
- *expt = LDBL_MIN_EXP - 1 - cnt;
+ *expt = DBL_MIN_EXP - 1 - cnt;
}
else
{
@@ -130,7 +132,7 @@ __mpn_extract_long_double (mp_ptr res_ptr, mp_size_t size,
res_ptr[N - 1] = res_ptr[0] >> (NUM_LEADING_ZEROS - cnt);
res_ptr[0] <<= BITS_PER_MP_LIMB - (NUM_LEADING_ZEROS - cnt);
}
- *expt = LDBL_MIN_EXP - 1
+ *expt = DBL_MIN_EXP - 1
- (BITS_PER_MP_LIMB - NUM_LEADING_ZEROS) - cnt;
}
#else
@@ -161,7 +163,7 @@ __mpn_extract_long_double (mp_ptr res_ptr, mp_size_t size,
for (; k >= 0; k--)
res_ptr[k] = 0;
- *expt = LDBL_MIN_EXP - 1 - l * BITS_PER_MP_LIMB - cnt;
+ *expt = DBL_MIN_EXP - 1 - l * BITS_PER_MP_LIMB - cnt;
#endif
}
}
--
1.7.10
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."