1/* scalbnq.c -- __float128 version of s_scalbn.c. 2 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz. 3 */ 4 5/* 6 * ==================================================== 7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 8 * 9 * Developed at SunPro, a Sun Microsystems, Inc. business. 10 * Permission to use, copy, modify, and distribute this 11 * software is freely granted, provided that this notice 12 * is preserved. 13 * ==================================================== 14 */ 15 16 17/* 18 * scalbnq (__float128 x, int n) 19 * scalbnq(x,n) returns x* 2**n computed by exponent 20 * manipulation rather than by actually performing an 21 * exponentiation or a multiplication. 22 */ 23 24#include "quadmath-imp.h" 25 26static const __float128 27two114 = 2.0769187434139310514121985316880384E+34Q, /* 0x4071000000000000, 0 */ 28twom114 = 4.8148248609680896326399448564623183E-35Q, /* 0x3F8D000000000000, 0 */ 29huge = 1.0E+4900Q, 30tiny = 1.0E-4900Q; 31 32__float128 33scalbnq (__float128 x, int n) 34{ 35 int64_t k,hx,lx; 36 GET_FLT128_WORDS64(hx,lx,x); 37 k = (hx>>48)&0x7fff; /* extract exponent */ 38 if (k==0) { /* 0 or subnormal x */ 39 if ((lx|(hx&0x7fffffffffffffffULL))==0) return x; /* +-0 */ 40 x *= two114; 41 GET_FLT128_MSW64(hx,x); 42 k = ((hx>>48)&0x7fff) - 114; 43 } 44 if (k==0x7fff) return x+x; /* NaN or Inf */ 45 if (n< -50000) return tiny*copysignq(tiny,x); /*underflow*/ 46 if (n> 50000 || k+n > 0x7ffe) 47 return huge*copysignq(huge,x); /* overflow */ 48 /* Now k and n are bounded we know that k = k+n does not 49 overflow. */ 50 k = k+n; 51 if (k > 0) /* normal result */ 52 {SET_FLT128_MSW64(x,(hx&0x8000ffffffffffffULL)|(k<<48)); return x;} 53 if (k <= -114) 54 return tiny*copysignq(tiny,x); /*underflow*/ 55 k += 114; /* subnormal result */ 56 SET_FLT128_MSW64(x,(hx&0x8000ffffffffffffULL)|(k<<48)); 57 return x*twom114; 58} 59