diff options
Diffstat (limited to 'sysdeps/ieee754/dbl-64/s_scalbn.c')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/s_scalbn.c | 61 |
1 files changed, 33 insertions, 28 deletions
diff --git a/sysdeps/ieee754/dbl-64/s_scalbn.c b/sysdeps/ieee754/dbl-64/s_scalbn.c index 1f302557ef..6e7d5ad217 100644 --- a/sysdeps/ieee754/dbl-64/s_scalbn.c +++ b/sysdeps/ieee754/dbl-64/s_scalbn.c @@ -20,38 +20,43 @@ #include <math_private.h> static const double -two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */ -twom54 = 5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */ -huge = 1.0e+300, -tiny = 1.0e-300; + two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */ + twom54 = 5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */ + huge = 1.0e+300, + tiny = 1.0e-300; double __scalbn (double x, int n) { - int32_t k,hx,lx; - EXTRACT_WORDS(hx,lx,x); - k = (hx&0x7ff00000)>>20; /* extract exponent */ - if (__builtin_expect(k==0, 0)) { /* 0 or subnormal x */ - if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */ - x *= two54; - GET_HIGH_WORD(hx,x); - k = ((hx&0x7ff00000)>>20) - 54; - } - if (__builtin_expect(k==0x7ff, 0)) return x+x; /* NaN or Inf */ - if (__builtin_expect(n< -50000, 0)) - return tiny*__copysign(tiny,x); /*underflow*/ - if (__builtin_expect(n> 50000 || k+n > 0x7fe, 0)) - return huge*__copysign(huge,x); /* overflow */ - /* Now k and n are bounded we know that k = k+n does not - overflow. */ - k = k+n; - if (__builtin_expect(k > 0, 1)) /* normal result */ - {SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20)); return x;} - if (k <= -54) - return tiny*__copysign(tiny,x); /*underflow*/ - k += 54; /* subnormal result */ - SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20)); - return x*twom54; + int32_t k, hx, lx; + EXTRACT_WORDS (hx, lx, x); + k = (hx & 0x7ff00000) >> 20; /* extract exponent */ + if (__builtin_expect (k == 0, 0)) /* 0 or subnormal x */ + { + if ((lx | (hx & 0x7fffffff)) == 0) + return x; /* +-0 */ + x *= two54; + GET_HIGH_WORD (hx, x); + k = ((hx & 0x7ff00000) >> 20) - 54; + } + if (__builtin_expect (k == 0x7ff, 0)) + return x + x; /* NaN or Inf */ + if (__builtin_expect (n < -50000, 0)) + return tiny * __copysign (tiny, x); /*underflow*/ + if (__builtin_expect (n > 50000 || k + n > 0x7fe, 0)) + return huge * __copysign (huge, x); /* overflow */ + /* Now k and n are bounded we know that k = k+n does not + overflow. */ + k = k + n; + if (__builtin_expect (k > 0, 1)) /* normal result */ + { + SET_HIGH_WORD (x, (hx & 0x800fffff) | (k << 20)); return x; + } + if (k <= -54) + return tiny * __copysign (tiny, x); /*underflow*/ + k += 54; /* subnormal result */ + SET_HIGH_WORD (x, (hx & 0x800fffff) | (k << 20)); + return x * twom54; } weak_alias (__scalbn, scalbn) #ifdef NO_LONG_DOUBLE |