From 257dd6af88e8bb4962a99a57f34d04e8265f31c8 Mon Sep 17 00:00:00 2001 From: Olaf Barthel Date: Tue, 11 Oct 2005 19:05:18 +0000 Subject: [PATCH] - Updated math_hypot.c to a newer (e_hypot.c 1.3 95/01/18) version from fdlibm which uses macros for manipulating the high and low words of a double, like the rest of fdlibm functions in clib2. The previous version would give bogus results when compiled with -O3 in clib2 which lead to "interesting" results (and lots of fun while searching for the problem) in Ghostscript. Wish I managed to track this down yesterday for 1.196 release... git-svn-id: file:///Users/olsen/Code/migration-svn-zu-git/logical-line-staging/clib2/trunk@15043 87f5fb63-7c3d-0410-a384-fd976d0f7a62 --- library/changes | 8 ++++++++ library/math_hypot.c | 47 +++++++++++++++++++++++++------------------- 2 files changed, 35 insertions(+), 20 deletions(-) diff --git a/library/changes b/library/changes index 9e7883a..16daba6 100644 --- a/library/changes +++ b/library/changes @@ -1,3 +1,11 @@ +- Updated math_hypot.c to a newer (e_hypot.c 1.3 95/01/18) version from + fdlibm which uses macros for manipulating the high and low words of a + double, like the rest of fdlibm functions in clib2. The previous version + would give bogus results when compiled with -O3 in clib2 which lead to + "interesting" results (and lots of fun while searching for the problem) + in Ghostscript. Wish I managed to track this down yesterday for 1.196 + release... + c.lib 1.196 (11.10.2005) - Removed the various workarounds associated with , required diff --git a/library/math_hypot.c b/library/math_hypot.c index f67692e..209a317 100644 --- a/library/math_hypot.c +++ b/library/math_hypot.c @@ -1,5 +1,5 @@ /* - * $Id: math_hypot.c,v 1.3 2005-02-25 10:14:21 obarthel Exp $ + * $Id: math_hypot.c,v 1.4 2005-10-11 19:05:18 theantony Exp $ * * :ts=4 * @@ -88,35 +88,40 @@ static const double one = 1.0; INLINE STATIC const double __hypot(double x,double y) { - int n0; double a=x,b=y,t1,t2,y1,y2,w; int j,k,ha,hb; - n0 = ((*(int*)&one)>>29)^1; /* high word index */ - ha = *(n0+(int*)&x)&0x7fffffff; /* high word of x */ - hb = *(n0+(int*)&y)&0x7fffffff; /* high word of y */ + GET_HIGH_WORD(ha,x); + ha &= 0x7fffffff; + GET_HIGH_WORD(hb,y); + hb &= 0x7fffffff; if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;} - *(n0+(int*)&a) = ha; /* a <- |a| */ - *(n0+(int*)&b) = hb; /* b <- |b| */ + SET_HIGH_WORD(a,ha); /* a <- |a| */ + SET_HIGH_WORD(b,hb); /* b <- |b| */ if((ha-hb)>0x3c00000) {return a+b;} /* x/y > 2**60 */ k=0; if(ha > 0x5f300000) { /* a>2**500 */ if(ha >= 0x7ff00000) { /* Inf or NaN */ + unsigned int low; w = a+b; /* for sNaN */ - if(((ha&0xfffff)|*(1-n0+(int*)&a))==0) w = a; - if(((hb^0x7ff00000)|*(1-n0+(int*)&b))==0) w = b; + GET_LOW_WORD(low,a); + if(((ha&0xfffff)|low)==0) w = a; + GET_LOW_WORD(low,b); + if(((hb^0x7ff00000)|low)==0) w = b; return w; } /* scale a and b by 2**-600 */ ha -= 0x25800000; hb -= 0x25800000; k += 600; - *(n0+(int*)&a) = ha; - *(n0+(int*)&b) = hb; + SET_HIGH_WORD(a,ha); + SET_HIGH_WORD(b,hb); } if(hb < 0x20b00000) { /* b < 2**-500 */ - if(hb <= 0x000fffff) { /* subnormal b or 0 */ - if((hb|(*(1-n0+(int*)&b)))==0) return a; + if(hb <= 0x000fffff) { /* subnormal b or 0 */ + unsigned int low; + GET_LOW_WORD(low,b); + if((hb|low)==0) return a; t1=0; - *(n0+(int*)&t1) = 0x7fd00000; /* t1=2^1022 */ + SET_HIGH_WORD(t1,0x7fd00000); /* t1=2^1022 */ b *= t1; a *= t1; k -= 1022; @@ -124,30 +129,32 @@ __hypot(double x,double y) ha += 0x25800000; /* a *= 2^600 */ hb += 0x25800000; /* b *= 2^600 */ k -= 600; - *(n0+(int*)&a) = ha; - *(n0+(int*)&b) = hb; + SET_HIGH_WORD(a,ha); + SET_HIGH_WORD(b,hb); } } /* medium size a and b */ w = a-b; if (w>b) { t1 = 0; - *(n0+(int*)&t1) = ha; + SET_HIGH_WORD(t1,ha); t2 = a-t1; w = sqrt(t1*t1-(b*(-b)-t2*(a+t1))); } else { a = a+a; y1 = 0; - *(n0+(int*)&y1) = hb; + SET_HIGH_WORD(y1,hb); y2 = b - y1; t1 = 0; - *(n0+(int*)&t1) = ha+0x00100000; + SET_HIGH_WORD(t1,ha+0x00100000); t2 = a - t1; w = sqrt(t1*y1-(w*(-w)-(t1*y2+t2*b))); } if(k!=0) { + unsigned int high; t1 = 1.0; - *(n0+(int*)&t1) += (k<<20); + GET_HIGH_WORD(high,t1); + SET_HIGH_WORD(t1,high+(k<<20)); return t1*w; } else return w; }