177ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao/* This file is distributed under the University of Illinois Open Source 277ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * License. See LICENSE.TXT for details. 377ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao */ 477ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 577ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao/* long double __floatditf(long long x); */ 677ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao/* This file implements the PowerPC long long -> long double conversion */ 777ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 877ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao#include "DD.h" 977ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao#include <stdint.h> 1077ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 1177ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liaolong double __floatditf(int64_t a) { 1277ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 1377ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao static const double twop32 = 0x1.0p32; 1477ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao static const double twop52 = 0x1.0p52; 1577ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 1677ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao doublebits low = { .d = twop52 }; 1777ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao low.x |= a & UINT64_C(0x00000000ffffffff); /* 0x1.0p52 + low 32 bits of a. */ 1877ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 1977ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao const double high_addend = (double)((int32_t)(a >> 32))*twop32 - twop52; 2077ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 2177ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao /* At this point, we have two double precision numbers 2277ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * high_addend and low.d, and we wish to return their sum 2377ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * as a canonicalized long double: 2477ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao */ 2577ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 2677ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao /* This implementation sets the inexact flag spuriously. 2777ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * This could be avoided, but at some substantial cost. 2877ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao */ 2977ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 3077ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao DD result; 3177ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 3277ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao result.s.hi = high_addend + low.d; 3377ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao result.s.lo = (high_addend - result.s.hi) + low.d; 3477ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 3577ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao return result.ld; 3677ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 3777ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao} 38