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| author | Bruce Evans <bde@FreeBSD.org> | 2002-06-17 15:28:59 +0000 |
|---|---|---|
| committer | Bruce Evans <bde@FreeBSD.org> | 2002-06-17 15:28:59 +0000 |
| commit | 3e2ec6ea886d3704fed746305b05bda766fe7f8a (patch) | |
| tree | 1fc315e9d825331ac4e0122b0f2e257a36001a1a /lib/msun | |
| parent | 93b99d6264fdb4305cae158b56bf916bec73181c (diff) | |
| download | src-3e2ec6ea886d3704fed746305b05bda766fe7f8a.tar.gz src-3e2ec6ea886d3704fed746305b05bda766fe7f8a.zip | |
e_pow.c:
Fixed pow(x, y) when x is very close to -1.0 and y is a very large odd
integer. E.g., pow(-1.0 - pow(2.0, -52.0), 1.0 + pow(2.0, 52.0)) was
0.0 instead of being very close to -exp(1.0).
PR: 39236
Submitted by: Stephen L Moshier <steve@moshier.net>
e_powf.c:
Apply the same patch although it is just cosmetic because odd integers
large enough to cause the problem are too large to be precisely represented
as floats.
MFC after: 1 week
Notes
Notes:
svn path=/head/; revision=98349
Diffstat (limited to 'lib/msun')
| -rw-r--r-- | lib/msun/src/e_pow.c | 2 | ||||
| -rw-r--r-- | lib/msun/src/e_powf.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/lib/msun/src/e_pow.c b/lib/msun/src/e_pow.c index 206f561984cf..e211ec706587 100644 --- a/lib/msun/src/e_pow.c +++ b/lib/msun/src/e_pow.c @@ -190,7 +190,7 @@ __ieee754_pow(double x, double y) if(ix>0x3ff00000) return (hy>0)? huge*huge:tiny*tiny; /* now |1-x| is tiny <= 2**-20, suffice to compute log(x) by x-x^2/2+x^3/3-x^4/4 */ - t = x-1; /* t has 20 trailing zeros */ + t = ax-1; /* t has 20 trailing zeros */ w = (t*t)*(0.5-t*(0.3333333333333333333333-t*0.25)); u = ivln2_h*t; /* ivln2_h has 21 sig. bits */ v = t*ivln2_l-w*ivln2; diff --git a/lib/msun/src/e_powf.c b/lib/msun/src/e_powf.c index 3301937a0666..0f1497fa17c3 100644 --- a/lib/msun/src/e_powf.c +++ b/lib/msun/src/e_powf.c @@ -130,7 +130,7 @@ __ieee754_powf(float x, float y) if(ix>0x3f800007) return (hy>0)? huge*huge:tiny*tiny; /* now |1-x| is tiny <= 2**-20, suffice to compute log(x) by x-x^2/2+x^3/3-x^4/4 */ - t = x-1; /* t has 20 trailing zeros */ + t = ax-1; /* t has 20 trailing zeros */ w = (t*t)*((float)0.5-t*((float)0.333333333333-t*(float)0.25)); u = ivln2_h*t; /* ivln2_h has 16 sig. bits */ v = t*ivln2_l-w*ivln2; |