2004-12-21 Jakub Jelinek <jakub@redhat.com>

	[BZ #725]
	* misc/efgcvt_r.c (FLOAT_MIN_10_EXP, FLOAT_MIN_10_NORM): Define.
	(ecvt_r): Special case denormals.
	* misc/qefgcvt_r.c (FLOAT_MIN_10_EXP, FLOAT_MIN_10_NORM): Define.
	* misc/tst-efgcvt.c: Include float.h.
	(ecvt_tests): Add 2 new tests.

diff --git a/misc/efgcvt_r.c b/misc/efgcvt_r.c
index ac2a5c45bf6cdaf1e972d3dceb114432bd101f4e..28bf170c810f0c3d4360aee33cbf4fafb50a9b08 100644 (file)
--- a/misc/efgcvt_r.c
+++ b/misc/efgcvt_r.c
@@ -31,6 +31,7 @@
 # define FUNC_PREFIX
 # define FLOAT_FMT_FLAG
 # define FLOAT_NAME_EXT
+# define FLOAT_MIN_10_EXP DBL_MIN_10_EXP
 # if DBL_MANT_DIG == 53
 #  define NDIGIT_MAX 17
 # elif DBL_MANT_DIG == 24
@@ -43,6 +44,17 @@
 #  error "NDIGIT_MAX must be precomputed"
 #  define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0)))
 # endif
+# if DBL_MIN_10_EXP == -37
+#  define FLOAT_MIN_10_NORM    1.0e-37
+# elif DBL_MIN_10_EXP == -307
+#  define FLOAT_MIN_10_NORM    1.0e-307
+# elif DBL_MIN_10_EXP == -4931
+#  define FLOAT_MIN_10_NORM    1.0e-4931
+# else
+/* libc can't depend on libm.  */
+#  error "FLOAT_MIN_10_NORM must be precomputed"
+#  define FLOAT_MIN_10_NORM    exp10 (DBL_MIN_10_EXP)
+# endif
 #endif
 
 #define APPEND(a, b) APPEND2 (a, b)
@@ -171,6 +183,17 @@ APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign, buf, len)
        d = -value;
       else
        d = value;
+      /* For denormalized numbers the d < 1.0 case below won't work,
+        as f can overflow to +Inf.  */
+      if (d < FLOAT_MIN_10_NORM)
+       {
+         value /= FLOAT_MIN_10_NORM;
+         if (value < 0.0)
+           d = -value;
+         else
+           d = value;
+         exponent += FLOAT_MIN_10_EXP;
+       }
       if (d < 1.0)
        {
          do

diff --git a/misc/qefgcvt_r.c b/misc/qefgcvt_r.c
index 66cc049ec8df206c60b88f8617177b074f7af6ef..d5b2a799b3ae0d3174d4c1120c0a0a9494ab5c38 100644 (file)
--- a/misc/qefgcvt_r.c
+++ b/misc/qefgcvt_r.c
@@ -24,6 +24,7 @@
 #define FUNC_PREFIX q
 #define FLOAT_FMT_FLAG "L"
 #define FLOAT_NAME_EXT l
+#define FLOAT_MIN_10_EXP LDBL_MIN_10_EXP
 #if LDBL_MANT_DIG == 64
 # define NDIGIT_MAX 21
 #elif LDBL_MANT_DIG == 53
@@ -40,5 +41,16 @@
 # error "NDIGIT_MAX must be precomputed"
 # define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * LDBL_MANT_DIG + 1.0)))
 #endif
+#if LDBL_MIN_10_EXP == -37
+# define FLOAT_MIN_10_NORM     1.0e-37L
+#elif LDBL_MIN_10_EXP == -307
+# define FLOAT_MIN_10_NORM     1.0e-307L
+#elif LDBL_MIN_10_EXP == -4931
+# define FLOAT_MIN_10_NORM     1.0e-4931L
+#else
+/* libc can't depend on libm.  */
+# error "FLOAT_MIN_10_NORM must be precomputed"
+# define FLOAT_MIN_10_NORM     exp10l (LDBL_MIN_10_EXP)
+#endif
 
 #include "efgcvt_r.c"

diff --git a/misc/tst-efgcvt.c b/misc/tst-efgcvt.c
index 91e5cf929edf24dfe2d571d6edbd26f16e0d9917..8a31e0280a932fb82c0b5dbc3b6ea778bc28a77c 100644 (file)
--- a/misc/tst-efgcvt.c
+++ b/misc/tst-efgcvt.c
@@ -20,6 +20,7 @@
 # define _GNU_SOURCE   1
 #endif
 
+#include <float.h>
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -59,6 +60,10 @@ static testcase ecvt_tests[] =
   { 123.01, -4, 3, "" },
   { 126.71, -4, 3, "" },
   { 0.0, 4, 1, "0000" },
+#if DBL_MANT_DIG == 53
+  { 0x1p-1074, 3, -323, "494" },
+  { -0x1p-1074, 3, -323, "494" },
+#endif
   /* -1.0 is end marker.  */
   { -1.0, 0, 0, "" }
 };