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113 lines
3.9 KiB
113 lines
3.9 KiB
# commit 62a728aeff93507ce5975f245a5f1d2046fb4503 |
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# Author: Alan Modra <amodra@gmail.com> |
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# Date: Sat Aug 17 18:27:19 2013 +0930 |
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# |
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# PowerPC floating point little-endian [6 of 15] |
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# http://sourceware.org/ml/libc-alpha/2013-07/msg00197.html |
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# |
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# A rewrite to make this code correct for little-endian. |
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# |
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# * sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c (mynumber): Replace |
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# union 32-bit int array member with 64-bit int array. |
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# (t515, tm256): Double rather than long double. |
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# (__ieee754_sqrtl): Rewrite using 64-bit arithmetic. |
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# |
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diff -urN glibc-2.17-c758a686/sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c glibc-2.17-c758a686/sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c |
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--- glibc-2.17-c758a686/sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c 2014-05-27 22:20:12.000000000 -0500 |
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+++ glibc-2.17-c758a686/sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c 2014-05-27 22:21:39.000000000 -0500 |
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@@ -34,15 +34,13 @@ |
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#include <math_private.h> |
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-typedef unsigned int int4; |
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-typedef union {int4 i[4]; long double x; double d[2]; } mynumber; |
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+typedef union {int64_t i[2]; long double x; double d[2]; } mynumber; |
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-static const mynumber |
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- t512 = {{0x5ff00000, 0x00000000, 0x00000000, 0x00000000 }}, /* 2^512 */ |
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- tm256 = {{0x2ff00000, 0x00000000, 0x00000000, 0x00000000 }}; /* 2^-256 */ |
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static const double |
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-two54 = 1.80143985094819840000e+16, /* 0x4350000000000000 */ |
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-twom54 = 5.55111512312578270212e-17; /* 0x3C90000000000000 */ |
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+ t512 = 0x1p512, |
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+ tm256 = 0x1p-256, |
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+ two54 = 0x1p54, /* 0x4350000000000000 */ |
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+ twom54 = 0x1p-54; /* 0x3C90000000000000 */ |
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/*********************************************************************/ |
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/* An ultimate sqrt routine. Given an IEEE double machine number x */ |
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@@ -54,56 +52,53 @@ |
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static const long double big = 134217728.0, big1 = 134217729.0; |
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long double t,s,i; |
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mynumber a,c; |
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- int4 k, l, m; |
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- int n; |
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+ uint64_t k, l; |
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+ int64_t m, n; |
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double d; |
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a.x=x; |
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- k=a.i[0] & 0x7fffffff; |
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+ k=a.i[0] & INT64_C(0x7fffffffffffffff); |
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/*----------------- 2^-1022 <= | x |< 2^1024 -----------------*/ |
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- if (k>0x000fffff && k<0x7ff00000) { |
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+ if (k>INT64_C(0x000fffff00000000) && k<INT64_C(0x7ff0000000000000)) { |
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if (x < 0) return (big1-big1)/(big-big); |
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- l = (k&0x001fffff)|0x3fe00000; |
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- if (((a.i[2] & 0x7fffffff) | a.i[3]) != 0) { |
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- n = (int) ((l - k) * 2) >> 21; |
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- m = (a.i[2] >> 20) & 0x7ff; |
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+ l = (k&INT64_C(0x001fffffffffffff))|INT64_C(0x3fe0000000000000); |
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+ if ((a.i[1] & INT64_C(0x7fffffffffffffff)) != 0) { |
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+ n = (int64_t) ((l - k) * 2) >> 53; |
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+ m = (a.i[1] >> 52) & 0x7ff; |
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if (m == 0) { |
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a.d[1] *= two54; |
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- m = ((a.i[2] >> 20) & 0x7ff) - 54; |
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+ m = ((a.i[1] >> 52) & 0x7ff) - 54; |
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} |
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m += n; |
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- if ((int) m > 0) |
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- a.i[2] = (a.i[2] & 0x800fffff) | (m << 20); |
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- else if ((int) m <= -54) { |
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- a.i[2] &= 0x80000000; |
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- a.i[3] = 0; |
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+ if (m > 0) |
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+ a.i[1] = (a.i[1] & INT64_C(0x800fffffffffffff)) | (m << 52); |
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+ else if (m <= -54) { |
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+ a.i[1] &= INT64_C(0x8000000000000000); |
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} else { |
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m += 54; |
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- a.i[2] = (a.i[2] & 0x800fffff) | (m << 20); |
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+ a.i[1] = (a.i[1] & INT64_C(0x800fffffffffffff)) | (m << 52); |
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a.d[1] *= twom54; |
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} |
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} |
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a.i[0] = l; |
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s = a.x; |
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d = __ieee754_sqrt (a.d[0]); |
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- c.i[0] = 0x20000000+((k&0x7fe00000)>>1); |
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+ c.i[0] = INT64_C(0x2000000000000000)+((k&INT64_C(0x7fe0000000000000))>>1); |
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c.i[1] = 0; |
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- c.i[2] = 0; |
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- c.i[3] = 0; |
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i = d; |
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t = 0.5L * (i + s / i); |
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i = 0.5L * (t + s / t); |
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return c.x * i; |
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} |
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else { |
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- if (k>=0x7ff00000) { |
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- if (a.i[0] == 0xfff00000 && a.i[1] == 0) |
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+ if (k>=INT64_C(0x7ff0000000000000)) { |
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+ if (a.i[0] == INT64_C(0xfff0000000000000)) |
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return (big1-big1)/(big-big); /* sqrt (-Inf) = NaN. */ |
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return x; /* sqrt (NaN) = NaN, sqrt (+Inf) = +Inf. */ |
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} |
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if (x == 0) return x; |
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if (x < 0) return (big1-big1)/(big-big); |
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- return tm256.x*__ieee754_sqrtl(x*t512.x); |
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+ return tm256*__ieee754_sqrtl(x*t512); |
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} |
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} |
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strong_alias (__ieee754_sqrtl, __sqrtl_finite)
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