This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[PATCH v2] Fix formatting of denormal IBM long double numbers


	[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."


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]