diff options
| author | Atsushi Nemoto <anemo@mba.ocn.ne.jp> | 2006-01-02 21:59:49 +0900 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2006-02-07 13:30:25 +0000 |
| commit | c5033d780310ddc5b679ed37ccefcdb87a30ef0c (patch) | |
| tree | 76d4dbd9b8a34a5540f94abf45a4ecb73ae2d0f0 /arch/mips | |
| parent | d4264f183967db9c2dae4275abb98eb1f79facb2 (diff) | |
| download | lwn-c5033d780310ddc5b679ed37ccefcdb87a30ef0c.tar.gz lwn-c5033d780310ddc5b679ed37ccefcdb87a30ef0c.zip | |
[MIPS] ieee754[sd]p_neg workaround
It looks glibc's pow() assumes an unary '-' operation for any number
(including NaNs) always inverts its sign bit (though IEEE754 does not
specify the sign bit for NaNs). This patch make the kernel math-emu
emulates real MIPS neg.[ds] instruction.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/math-emu/dp_simple.c | 14 | ||||
| -rw-r--r-- | arch/mips/math-emu/sp_simple.c | 14 |
2 files changed, 20 insertions, 8 deletions
diff --git a/arch/mips/math-emu/dp_simple.c b/arch/mips/math-emu/dp_simple.c index 495c1ac94298..1c555e6c6a9f 100644 --- a/arch/mips/math-emu/dp_simple.c +++ b/arch/mips/math-emu/dp_simple.c @@ -48,16 +48,22 @@ ieee754dp ieee754dp_neg(ieee754dp x) CLEARCX; FLUSHXDP; + /* + * Invert the sign ALWAYS to prevent an endless recursion on + * pow() in libc. + */ + /* quick fix up */ + DPSIGN(x) ^= 1; + if (xc == IEEE754_CLASS_SNAN) { + ieee754dp y = ieee754dp_indef(); SETCX(IEEE754_INVALID_OPERATION); - return ieee754dp_nanxcpt(ieee754dp_indef(), "neg"); + DPSIGN(y) = DPSIGN(x); + return ieee754dp_nanxcpt(y, "neg"); } if (ieee754dp_isnan(x)) /* but not infinity */ return ieee754dp_nanxcpt(x, "neg", x); - - /* quick fix up */ - DPSIGN(x) ^= 1; return x; } diff --git a/arch/mips/math-emu/sp_simple.c b/arch/mips/math-emu/sp_simple.c index c809830dffb4..770f0f4677cd 100644 --- a/arch/mips/math-emu/sp_simple.c +++ b/arch/mips/math-emu/sp_simple.c @@ -48,16 +48,22 @@ ieee754sp ieee754sp_neg(ieee754sp x) CLEARCX; FLUSHXSP; + /* + * Invert the sign ALWAYS to prevent an endless recursion on + * pow() in libc. + */ + /* quick fix up */ + SPSIGN(x) ^= 1; + if (xc == IEEE754_CLASS_SNAN) { + ieee754sp y = ieee754sp_indef(); SETCX(IEEE754_INVALID_OPERATION); - return ieee754sp_nanxcpt(ieee754sp_indef(), "neg"); + SPSIGN(y) = SPSIGN(x); + return ieee754sp_nanxcpt(y, "neg"); } if (ieee754sp_isnan(x)) /* but not infinity */ return ieee754sp_nanxcpt(x, "neg", x); - - /* quick fix up */ - SPSIGN(x) ^= 1; return x; } |