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author | Ben Cheng <bccheng@google.com> | 2014-03-25 22:37:19 -0700 |
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committer | Ben Cheng <bccheng@google.com> | 2014-03-25 22:37:19 -0700 |
commit | 1bc5aee63eb72b341f506ad058502cd0361f0d10 (patch) | |
tree | c607e8252f3405424ff15bc2d00aa38dadbb2518 /gcc-4.9/libquadmath/math/sqrtq.c | |
parent | 283a0bf58fcf333c58a2a92c3ebbc41fb9eb1fdb (diff) | |
download | toolchain_gcc-1bc5aee63eb72b341f506ad058502cd0361f0d10.tar.gz toolchain_gcc-1bc5aee63eb72b341f506ad058502cd0361f0d10.tar.bz2 toolchain_gcc-1bc5aee63eb72b341f506ad058502cd0361f0d10.zip |
Initial checkin of GCC 4.9.0 from trunk (r208799).
Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba
Diffstat (limited to 'gcc-4.9/libquadmath/math/sqrtq.c')
-rw-r--r-- | gcc-4.9/libquadmath/math/sqrtq.c | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/gcc-4.9/libquadmath/math/sqrtq.c b/gcc-4.9/libquadmath/math/sqrtq.c new file mode 100644 index 000000000..f63c0d1f6 --- /dev/null +++ b/gcc-4.9/libquadmath/math/sqrtq.c @@ -0,0 +1,60 @@ +#include "quadmath-imp.h" +#include <math.h> +#include <float.h> + +__float128 +sqrtq (const __float128 x) +{ + __float128 y; + int exp; + + if (isnanq (x) || (isinfq (x) && x > 0)) + return x; + + if (x == 0) + return x; + + if (x < 0) + { + /* Return NaN with invalid signal. */ + return (x - x) / (x - x); + } + + if (x <= DBL_MAX && x >= DBL_MIN) + { + /* Use double result as starting point. */ + y = sqrt ((double) x); + + /* Two Newton iterations. */ + y -= 0.5q * (y - x / y); + y -= 0.5q * (y - x / y); + return y; + } + +#ifdef HAVE_SQRTL + if (x <= LDBL_MAX && x >= LDBL_MIN) + { + /* Use long double result as starting point. */ + y = sqrtl ((long double) x); + + /* One Newton iteration. */ + y -= 0.5q * (y - x / y); + return y; + } +#endif + + /* If we're outside of the range of C types, we have to compute + the initial guess the hard way. */ + y = frexpq (x, &exp); + if (exp % 2) + y *= 2, exp--; + + y = sqrt (y); + y = scalbnq (y, exp / 2); + + /* Two Newton iterations. */ + y -= 0.5q * (y - x / y); + y -= 0.5q * (y - x / y); + return y; +} + |