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Unified Diff: fusl/src/math/log10.c

Issue 1714623002: [fusl] clang-format fusl (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: headers too Created 4 years, 10 months ago
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Index: fusl/src/math/log10.c
diff --git a/fusl/src/math/log10.c b/fusl/src/math/log10.c
index 81026876b223d4f56d6c2542b18898d6105aa34d..621e15e66c3935aba7a96e09093b6404f943eb95 100644
--- a/fusl/src/math/log10.c
+++ b/fusl/src/math/log10.c
@@ -20,82 +20,84 @@
#include <math.h>
#include <stdint.h>
-static const double
-ivln10hi = 4.34294481878168880939e-01, /* 0x3fdbcb7b, 0x15200000 */
-ivln10lo = 2.50829467116452752298e-11, /* 0x3dbb9438, 0xca9aadd5 */
-log10_2hi = 3.01029995663611771306e-01, /* 0x3FD34413, 0x509F6000 */
-log10_2lo = 3.69423907715893078616e-13, /* 0x3D59FEF3, 0x11F12B36 */
-Lg1 = 6.666666666666735130e-01, /* 3FE55555 55555593 */
-Lg2 = 3.999999999940941908e-01, /* 3FD99999 9997FA04 */
-Lg3 = 2.857142874366239149e-01, /* 3FD24924 94229359 */
-Lg4 = 2.222219843214978396e-01, /* 3FCC71C5 1D8E78AF */
-Lg5 = 1.818357216161805012e-01, /* 3FC74664 96CB03DE */
-Lg6 = 1.531383769920937332e-01, /* 3FC39A09 D078C69F */
-Lg7 = 1.479819860511658591e-01; /* 3FC2F112 DF3E5244 */
+static const double ivln10hi =
+ 4.34294481878168880939e-01, /* 0x3fdbcb7b, 0x15200000 */
+ ivln10lo = 2.50829467116452752298e-11, /* 0x3dbb9438, 0xca9aadd5 */
+ log10_2hi = 3.01029995663611771306e-01, /* 0x3FD34413, 0x509F6000 */
+ log10_2lo = 3.69423907715893078616e-13, /* 0x3D59FEF3, 0x11F12B36 */
+ Lg1 = 6.666666666666735130e-01, /* 3FE55555 55555593 */
+ Lg2 = 3.999999999940941908e-01, /* 3FD99999 9997FA04 */
+ Lg3 = 2.857142874366239149e-01, /* 3FD24924 94229359 */
+ Lg4 = 2.222219843214978396e-01, /* 3FCC71C5 1D8E78AF */
+ Lg5 = 1.818357216161805012e-01, /* 3FC74664 96CB03DE */
+ Lg6 = 1.531383769920937332e-01, /* 3FC39A09 D078C69F */
+ Lg7 = 1.479819860511658591e-01; /* 3FC2F112 DF3E5244 */
-double log10(double x)
-{
- union {double f; uint64_t i;} u = {x};
- double_t hfsq,f,s,z,R,w,t1,t2,dk,y,hi,lo,val_hi,val_lo;
- uint32_t hx;
- int k;
+double log10(double x) {
+ union {
+ double f;
+ uint64_t i;
+ } u = {x};
+ double_t hfsq, f, s, z, R, w, t1, t2, dk, y, hi, lo, val_hi, val_lo;
+ uint32_t hx;
+ int k;
- hx = u.i>>32;
- k = 0;
- if (hx < 0x00100000 || hx>>31) {
- if (u.i<<1 == 0)
- return -1/(x*x); /* log(+-0)=-inf */
- if (hx>>31)
- return (x-x)/0.0; /* log(-#) = NaN */
- /* subnormal number, scale x up */
- k -= 54;
- x *= 0x1p54;
- u.f = x;
- hx = u.i>>32;
- } else if (hx >= 0x7ff00000) {
- return x;
- } else if (hx == 0x3ff00000 && u.i<<32 == 0)
- return 0;
+ hx = u.i >> 32;
+ k = 0;
+ if (hx < 0x00100000 || hx >> 31) {
+ if (u.i << 1 == 0)
+ return -1 / (x * x); /* log(+-0)=-inf */
+ if (hx >> 31)
+ return (x - x) / 0.0; /* log(-#) = NaN */
+ /* subnormal number, scale x up */
+ k -= 54;
+ x *= 0x1p54;
+ u.f = x;
+ hx = u.i >> 32;
+ } else if (hx >= 0x7ff00000) {
+ return x;
+ } else if (hx == 0x3ff00000 && u.i << 32 == 0)
+ return 0;
- /* reduce x into [sqrt(2)/2, sqrt(2)] */
- hx += 0x3ff00000 - 0x3fe6a09e;
- k += (int)(hx>>20) - 0x3ff;
- hx = (hx&0x000fffff) + 0x3fe6a09e;
- u.i = (uint64_t)hx<<32 | (u.i&0xffffffff);
- x = u.f;
+ /* reduce x into [sqrt(2)/2, sqrt(2)] */
+ hx += 0x3ff00000 - 0x3fe6a09e;
+ k += (int)(hx >> 20) - 0x3ff;
+ hx = (hx & 0x000fffff) + 0x3fe6a09e;
+ u.i = (uint64_t)hx << 32 | (u.i & 0xffffffff);
+ x = u.f;
- f = x - 1.0;
- hfsq = 0.5*f*f;
- s = f/(2.0+f);
- z = s*s;
- w = z*z;
- t1 = w*(Lg2+w*(Lg4+w*Lg6));
- t2 = z*(Lg1+w*(Lg3+w*(Lg5+w*Lg7)));
- R = t2 + t1;
+ f = x - 1.0;
+ hfsq = 0.5 * f * f;
+ s = f / (2.0 + f);
+ z = s * s;
+ w = z * z;
+ t1 = w * (Lg2 + w * (Lg4 + w * Lg6));
+ t2 = z * (Lg1 + w * (Lg3 + w * (Lg5 + w * Lg7)));
+ R = t2 + t1;
- /* See log2.c for details. */
- /* hi+lo = f - hfsq + s*(hfsq+R) ~ log(1+f) */
- hi = f - hfsq;
- u.f = hi;
- u.i &= (uint64_t)-1<<32;
- hi = u.f;
- lo = f - hi - hfsq + s*(hfsq+R);
+ /* See log2.c for details. */
+ /* hi+lo = f - hfsq + s*(hfsq+R) ~ log(1+f) */
+ hi = f - hfsq;
+ u.f = hi;
+ u.i &= (uint64_t)-1 << 32;
+ hi = u.f;
+ lo = f - hi - hfsq + s * (hfsq + R);
- /* val_hi+val_lo ~ log10(1+f) + k*log10(2) */
- val_hi = hi*ivln10hi;
- dk = k;
- y = dk*log10_2hi;
- val_lo = dk*log10_2lo + (lo+hi)*ivln10lo + lo*ivln10hi;
+ /* val_hi+val_lo ~ log10(1+f) + k*log10(2) */
+ val_hi = hi * ivln10hi;
+ dk = k;
+ y = dk * log10_2hi;
+ val_lo = dk * log10_2lo + (lo + hi) * ivln10lo + lo * ivln10hi;
- /*
- * Extra precision in for adding y is not strictly needed
- * since there is no very large cancellation near x = sqrt(2) or
- * x = 1/sqrt(2), but we do it anyway since it costs little on CPUs
- * with some parallelism and it reduces the error for many args.
- */
- w = y + val_hi;
- val_lo += (y - w) + val_hi;
- val_hi = w;
+ /*
+ * Extra precision in for adding y is not strictly needed
+ * since there is no very large cancellation near x = sqrt(2) or
+ * x = 1/sqrt(2), but we do it anyway since it costs little on CPUs
+ * with some parallelism and it reduces the error for many args.
+ */
+ w = y + val_hi;
+ val_lo += (y - w) + val_hi;
+ val_hi = w;
- return val_lo + val_hi;
+ return val_lo + val_hi;
}

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