Index: fusl/src/math/log10f.c |
diff --git a/fusl/src/math/log10f.c b/fusl/src/math/log10f.c |
index 9ca2f017da666e2a4da75df66f1ab846eb0537e9..19584702c9efb16321c6c9bfb6e8e0a7ca9bd240 100644 |
--- a/fusl/src/math/log10f.c |
+++ b/fusl/src/math/log10f.c |
@@ -16,62 +16,64 @@ |
#include <math.h> |
#include <stdint.h> |
-static const float |
-ivln10hi = 4.3432617188e-01, /* 0x3ede6000 */ |
-ivln10lo = -3.1689971365e-05, /* 0xb804ead9 */ |
-log10_2hi = 3.0102920532e-01, /* 0x3e9a2080 */ |
-log10_2lo = 7.9034151668e-07, /* 0x355427db */ |
-/* |(log(1+s)-log(1-s))/s - Lg(s)| < 2**-34.24 (~[-4.95e-11, 4.97e-11]). */ |
-Lg1 = 0xaaaaaa.0p-24, /* 0.66666662693 */ |
-Lg2 = 0xccce13.0p-25, /* 0.40000972152 */ |
-Lg3 = 0x91e9ee.0p-25, /* 0.28498786688 */ |
-Lg4 = 0xf89e26.0p-26; /* 0.24279078841 */ |
+static const float ivln10hi = 4.3432617188e-01, /* 0x3ede6000 */ |
+ ivln10lo = -3.1689971365e-05, /* 0xb804ead9 */ |
+ log10_2hi = 3.0102920532e-01, /* 0x3e9a2080 */ |
+ log10_2lo = 7.9034151668e-07, /* 0x355427db */ |
+ /* |(log(1+s)-log(1-s))/s - Lg(s)| < 2**-34.24 (~[-4.95e-11, 4.97e-11]). */ |
+ Lg1 = 0xaaaaaa.0p-24, /* 0.66666662693 */ |
+ Lg2 = 0xccce13.0p-25, /* 0.40000972152 */ |
+ Lg3 = 0x91e9ee.0p-25, /* 0.28498786688 */ |
+ Lg4 = 0xf89e26.0p-26; /* 0.24279078841 */ |
-float log10f(float x) |
-{ |
- union {float f; uint32_t i;} u = {x}; |
- float_t hfsq,f,s,z,R,w,t1,t2,dk,hi,lo; |
- uint32_t ix; |
- int k; |
+float log10f(float x) { |
+ union { |
+ float f; |
+ uint32_t i; |
+ } u = {x}; |
+ float_t hfsq, f, s, z, R, w, t1, t2, dk, hi, lo; |
+ uint32_t ix; |
+ int k; |
- ix = u.i; |
- k = 0; |
- if (ix < 0x00800000 || ix>>31) { /* x < 2**-126 */ |
- if (ix<<1 == 0) |
- return -1/(x*x); /* log(+-0)=-inf */ |
- if (ix>>31) |
- return (x-x)/0.0f; /* log(-#) = NaN */ |
- /* subnormal number, scale up x */ |
- k -= 25; |
- x *= 0x1p25f; |
- u.f = x; |
- ix = u.i; |
- } else if (ix >= 0x7f800000) { |
- return x; |
- } else if (ix == 0x3f800000) |
- return 0; |
+ ix = u.i; |
+ k = 0; |
+ if (ix < 0x00800000 || ix >> 31) { /* x < 2**-126 */ |
+ if (ix << 1 == 0) |
+ return -1 / (x * x); /* log(+-0)=-inf */ |
+ if (ix >> 31) |
+ return (x - x) / 0.0f; /* log(-#) = NaN */ |
+ /* subnormal number, scale up x */ |
+ k -= 25; |
+ x *= 0x1p25f; |
+ u.f = x; |
+ ix = u.i; |
+ } else if (ix >= 0x7f800000) { |
+ return x; |
+ } else if (ix == 0x3f800000) |
+ return 0; |
- /* reduce x into [sqrt(2)/2, sqrt(2)] */ |
- ix += 0x3f800000 - 0x3f3504f3; |
- k += (int)(ix>>23) - 0x7f; |
- ix = (ix&0x007fffff) + 0x3f3504f3; |
- u.i = ix; |
- x = u.f; |
+ /* reduce x into [sqrt(2)/2, sqrt(2)] */ |
+ ix += 0x3f800000 - 0x3f3504f3; |
+ k += (int)(ix >> 23) - 0x7f; |
+ ix = (ix & 0x007fffff) + 0x3f3504f3; |
+ u.i = ix; |
+ x = u.f; |
- f = x - 1.0f; |
- s = f/(2.0f + f); |
- z = s*s; |
- w = z*z; |
- t1= w*(Lg2+w*Lg4); |
- t2= z*(Lg1+w*Lg3); |
- R = t2 + t1; |
- hfsq = 0.5f*f*f; |
+ f = x - 1.0f; |
+ s = f / (2.0f + f); |
+ z = s * s; |
+ w = z * z; |
+ t1 = w * (Lg2 + w * Lg4); |
+ t2 = z * (Lg1 + w * Lg3); |
+ R = t2 + t1; |
+ hfsq = 0.5f * f * f; |
- hi = f - hfsq; |
- u.f = hi; |
- u.i &= 0xfffff000; |
- hi = u.f; |
- lo = f - hi - hfsq + s*(hfsq+R); |
- dk = k; |
- return dk*log10_2lo + (lo+hi)*ivln10lo + lo*ivln10hi + hi*ivln10hi + dk*log10_2hi; |
+ hi = f - hfsq; |
+ u.f = hi; |
+ u.i &= 0xfffff000; |
+ hi = u.f; |
+ lo = f - hi - hfsq + s * (hfsq + R); |
+ dk = k; |
+ return dk * log10_2lo + (lo + hi) * ivln10lo + lo * ivln10hi + hi * ivln10hi + |
+ dk * log10_2hi; |
} |