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| author | Joseph Myers <joseph@codesourcery.com> | 2015-05-14 23:38:07 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2015-05-14 23:38:07 +0000 |
| commit | 0b7a5f920163d03806d7c5d9d1c83b16942c9496 (patch) | |
| tree | a108347db6f5f094bf917214f562b9a3a7ae8b04 /sysdeps/i386/fpu/s_log1pf.S | |
| parent | 95b07fbcc702a83b421cb5d0488ba2817d3123c1 (diff) | |
| download | glibc-0b7a5f920163d03806d7c5d9d1c83b16942c9496.tar.gz glibc-0b7a5f920163d03806d7c5d9d1c83b16942c9496.tar.xz glibc-0b7a5f920163d03806d7c5d9d1c83b16942c9496.zip | |
Fix log1p missing underflows (bug 16339).
Similar to various other bugs in this area, some log1p implementations do not raise the underflow exception for subnormal arguments, when the result is tiny and inexact. This patch forces the exception in a similar way to previous fixes. (The ldbl-128ibm implementation doesn't currently need any change as it already generates this exception, albeit through code that would generate spurious exceptions in other cases; special code for this issue will only be needed there when fixing the spurious exceptions.) Tested for x86_64, x86, powerpc and mips64. [BZ #16339] * sysdeps/i386/fpu/s_log1p.S (dbl_min): New object. (__log1p): Force underflow exception for results with small absolute value. * sysdeps/i386/fpu/s_log1pf.S (flt_min): New object. (__log1pf): Force underflow exception for results with small absolute value. * sysdeps/ieee754/dbl-64/s_log1p.c: Include <float.h>. (__log1p): Force underflow exception for results with small absolute value. * sysdeps/ieee754/flt-32/s_log1pf.c: Include <float.h>. (__log1pf): Force underflow exception for results with small absolute value. * sysdeps/ieee754/ldbl-128/s_log1pl.c: Include <float.h>. (__log1pl): Force underflow exception for results with small absolute value. * math/auto-libm-test-in: Do not allow missing underflow exceptions from log1p. * math/auto-libm-test-out: Regenerated.
Diffstat (limited to 'sysdeps/i386/fpu/s_log1pf.S')
| -rw-r--r-- | sysdeps/i386/fpu/s_log1pf.S | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/sysdeps/i386/fpu/s_log1pf.S b/sysdeps/i386/fpu/s_log1pf.S index b071e7372d..8fca22e4ff 100644 --- a/sysdeps/i386/fpu/s_log1pf.S +++ b/sysdeps/i386/fpu/s_log1pf.S @@ -17,6 +17,13 @@ RCSID("$NetBSD: s_log1pf.S,v 1.4 1995/05/09 00:13:05 jtc Exp $") limit: .float 0.29 one: .float 1.0 + .section .rodata.cst4,"aM",@progbits,4 + + .p2align 2 + .type flt_min,@object +flt_min: .byte 0, 0, 0x80, 0 + ASM_SIZE_DIRECTIVE(flt_min) + /* * Use the fyl2xp1 function when the argument is in the range -0.29 to 0.29, * otherwise fyl2x with the needed extra computation. @@ -55,7 +62,25 @@ ENTRY(__log1pf) ret 2: fyl2xp1 - ret +#ifdef PIC + flds flt_min@GOTOFF(%edx) +#else + flds flt_min +#endif + fld %st(1) + fabs + fucompp + fnstsw + sahf + jnc 1f + subl $4, %esp + cfi_adjust_cfa_offset (4) + fld %st(0) + fmul %st(0) + fstps (%esp) + addl $4, %esp + cfi_adjust_cfa_offset (-4) +1: ret 3: jp 4b // in case x is ħInf fstp %st(1) |