Re: printf("%La\n", 1e1000L) crashes with segv.
Takashi Yano <[email protected]>
| Newsgroups | gmane.comp.lib.newlib |
|---|---|
| Message-ID | <[email protected]> |
On Sun, 28 Nov 2021 16:49:53 +0900
Takashi Yano wrote:
> I noticed that printf("%La\n", 1e1000L) crashes with segv.
> I confirmed this in 32bit cygwin, however, I guess this is
> newlib issue.
>
> Is this the known issue?
I found that the main cause of this issue is lack of frexpl()
function. This is not implemented yet in newlib.
I have made a patch which implements frexpl() to fix this issue.
Please see attachd patch.
--
Takashi Yano <[email protected]>
0001-stdio-Fix-issue-of-printing-La-format-with-large-exp.patch
(application/octet-stream, 6 KB)
From 2929df82449dc65eb75350e5d038968698582330 Mon Sep 17 00:00:00 2001 From: Takashi Yano <[email protected]> Date: Mon, 29 Nov 2021 19:50:47 +0900 Subject: [PATCH] stdio: Fix issue of printing "%La" format with large exp part. - Currently, printf("%La\n", 1e1000L) crashes with segv due to lack of frexpl() function. With this patch, frexpl() function has been implemented in libm to solve this issue. Addresses: https://sourceware.org/pipermail/newlib/2021/018718.html --- newlib/Makefile.am | 2 +- newlib/Makefile.in | 3 +- newlib/libc/include/math.h | 1 + newlib/libc/stdio/vfprintf.c | 5 +-- newlib/libc/stdio/vfwprintf.c | 5 +-- newlib/libm/common/frexpl.c | 72 ++++++++++++++++++++++++++++++++++- 6 files changed, 77 insertions(+), 11 deletions(-) diff --git a/newlib/Makefile.am b/newlib/Makefile.am index d3da43a4b..1235adb8b 100644 --- a/newlib/Makefile.am +++ b/newlib/Makefile.am @@ -105,7 +105,7 @@ MATHOBJS_IN_LIBC = \ $(lpfx)s_isnand.$(oext) $(lpfx)sf_isnanf.$(oext) \ $(lpfx)s_nan.$(oext) $(lpfx)sf_nan.$(oext) \ $(lpfx)s_ldexp.$(oext) $(lpfx)sf_ldexp.$(oext) \ - $(lpfx)s_frexp.$(oext) $(lpfx)sf_frexp.$(oext) \ + $(lpfx)s_frexp.$(oext) $(lpfx)sf_frexp.$(oext) $(lpfx)frexpl.$(oext) \ $(lpfx)s_modf.$(oext) \ $(lpfx)sf_modf.$(oext) $(lpfx)s_scalbn.$(oext) \ $(lpfx)sf_scalbn.$(oext) \ diff --git a/newlib/Makefile.in b/newlib/Makefile.in index bf15dfea3..68417953d 100644 --- a/newlib/Makefile.in +++ b/newlib/Makefile.in @@ -312,6 +312,7 @@ pdfdir = @pdfdir@ prefix = @prefix@ program_transform_name = @program_transform_name@ psdir = @psdir@ +runstatedir = @runstatedir@ sbindir = @sbindir@ shared_machine_dir = @shared_machine_dir@ sharedstatedir = @sharedstatedir@ @@ -415,7 +416,7 @@ MATHOBJS_IN_LIBC = \ $(lpfx)s_isnand.$(oext) $(lpfx)sf_isnanf.$(oext) \ $(lpfx)s_nan.$(oext) $(lpfx)sf_nan.$(oext) \ $(lpfx)s_ldexp.$(oext) $(lpfx)sf_ldexp.$(oext) \ - $(lpfx)s_frexp.$(oext) $(lpfx)sf_frexp.$(oext) \ + $(lpfx)s_frexp.$(oext) $(lpfx)sf_frexp.$(oext) $(lpfx)frexpl.$(oext) \ $(lpfx)s_modf.$(oext) \ $(lpfx)sf_modf.$(oext) $(lpfx)s_scalbn.$(oext) \ $(lpfx)sf_scalbn.$(oext) \ diff --git a/newlib/libc/include/math.h b/newlib/libc/include/math.h index 0b6494e6a..799ac494a 100644 --- a/newlib/libc/include/math.h +++ b/newlib/libc/include/math.h @@ -509,6 +509,7 @@ extern long double erfcl (long double); #else /* !_LDBL_EQ_DBL && !__CYGWIN__ */ extern long double hypotl (long double, long double); extern long double sqrtl (long double); +extern long double frexpl (long double, int *); #ifdef __i386__ /* Other long double precision functions. */ extern _LONG_DOUBLE rintl (_LONG_DOUBLE); diff --git a/newlib/libc/stdio/vfprintf.c b/newlib/libc/stdio/vfprintf.c index 1aaf05aa4..c1483c0ac 100644 --- a/newlib/libc/stdio/vfprintf.c +++ b/newlib/libc/stdio/vfprintf.c @@ -517,10 +517,7 @@ extern int _ldcheck (_LONG_DOUBLE *); # define _PRINTF_FLOAT_TYPE _LONG_DOUBLE # define _DTOA_R _ldtoa_r -/* FIXME - frexpl is not yet supported; and cvt infloops if (double)f - converts a finite value into infinity. */ -/* # define FREXP frexpl */ -# define FREXP(f,e) ((_LONG_DOUBLE) frexp ((double)f, e)) +# define FREXP frexpl # endif /* !_NO_LONGDBL */ static char *cvt(struct _reent *, _PRINTF_FLOAT_TYPE, int, int, char *, int *, diff --git a/newlib/libc/stdio/vfwprintf.c b/newlib/libc/stdio/vfwprintf.c index 980b31e3b..7384b37d3 100644 --- a/newlib/libc/stdio/vfwprintf.c +++ b/newlib/libc/stdio/vfwprintf.c @@ -243,10 +243,7 @@ extern int _ldcheck (_LONG_DOUBLE *); # define _PRINTF_FLOAT_TYPE _LONG_DOUBLE # define _DTOA_R _ldtoa_r -/* FIXME - frexpl is not yet supported; and cvt infloops if (double)f - converts a finite value into infinity. */ -/* # define FREXP frexpl */ -# define FREXP(f,e) ((_LONG_DOUBLE) frexp ((double)f, e)) +# define FREXP frexpl # endif /* !_NO_LONGDBL */ static wchar_t *wcvt(struct _reent *, _PRINTF_FLOAT_TYPE, int, int, wchar_t *, diff --git a/newlib/libm/common/frexpl.c b/newlib/libm/common/frexpl.c index 79e41fd9e..42ea41062 100644 --- a/newlib/libm/common/frexpl.c +++ b/newlib/libm/common/frexpl.c @@ -29,10 +29,11 @@ POSSIBILITY OF SUCH DAMAGE. */ #include <math.h> +#include <float.h> #include "local.h" /* On platforms where long double is as wide as double. */ -#ifdef _LDBL_EQ_DBL +#if defined(_LDBL_EQ_DBL) || (LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024) long double frexpl (long double x, int *eptr) { @@ -40,3 +41,72 @@ frexpl (long double x, int *eptr) } #endif +#if (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384 +# if (LDBL_MANT_DIG == 64) /* 80-bit long double */ +union ldbl { + long double x; + struct { +# ifdef __IEEE_LITTLE_ENDIAN /* for Intel CPU */ + __uint32_t fracl; + __uint32_t frach; + __uint32_t sexp:16; + __uint32_t pad:16; +# endif +# ifdef __IEEE_BIG_ENDIAN /* for m86k */ + __uint32_t sexp:16; + __uint32_t pad:16 + __uint32_t frach; + __uint32_t fracl; +# endif + } u32; +}; +# else /* LDBL_MANT_DIG == 113, 128-bit long double */ +union ldbl { + long double x; + struct { +# ifdef __IEEE_LITTLE_ENDIAN + __uint32_t fracl; + __uint32_t fraclm; + __uint32_t frachm; + __uint32_t frach:16; + __uint32_t sexp:16; +# endif +# ifdef __IEEE_BIG_ENDIAN +#ifndef ___IEEE_BYTES_LITTLE_ENDIAN + __uint32_t sexp:16; + __uint32_t frach:16; +#else /* ARMEL without __VFP_FP__ */ + __uint32_t frach:16; + __uint32_t sexp:16; +#endif + __uint32_t frachm; + __uint32_t fraclm; + __uint32_t fracl; +# endif + } u32; +}; +# endif + +static const double two114 = 0x1p114; + +long double +frexpl (long double x, int *eptr) +{ + union ldbl u; + u.x = x; + int e = u.u32.sexp & 0x7fff; + *eptr = 0; + if (e == 0x7fff || x == 0) + return x; /* 0,inf,nan */ + if (e == 0) + { + x *= two114; + u.x = x; + e = u.u32.sexp & 0x7fff; + *eptr -= 114; + } + *eptr += e - 16382; + u.u32.sexp = (u.u32.sexp & 0x8000) | 0x3ffe; + return u.x; +} +#endif /* End of 80-bit or 128-bit long double */ -- 2.33.0