From c5033d780310ddc5b679ed37ccefcdb87a30ef0c Mon Sep 17 00:00:00 2001 From: Atsushi Nemoto Date: Mon, 2 Jan 2006 21:59:49 +0900 Subject: [PATCH] [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 Signed-off-by: Ralf Baechle --- arch/mips/math-emu/dp_simple.c | 14 ++++++++++---- 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; } -- 2.30.2