1 /* ===-- floatundixf.c - Implement __floatundixf ---------------------------=== 2 * 3 * The LLVM Compiler Infrastructure 4 * 5 * This file is distributed under the University of Illinois Open Source 6 * License. See LICENSE.TXT for details. 7 * 8 * ===----------------------------------------------------------------------=== 9 * 10 * This file implements __floatundixf for the compiler_rt library. 11 * 12 * ===----------------------------------------------------------------------=== 13 */ 14 15 #if !_ARCH_PPC 16 17 #include "int_lib.h" 18 19 /* Returns: convert a to a long double, rounding toward even. */ 20 21 /* Assumption: long double is a IEEE 80 bit floating point type padded to 128 bits 22 * du_int is a 64 bit integral type 23 */ 24 25 /* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee | 26 * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm 27 */ 28 long double 29 __floatundixf(du_int a) 30 { 31 if (a == 0) 32 return 0.0; 33 const unsigned N = sizeof(du_int) * CHAR_BIT; 34 int clz = __builtin_clzll(a); 35 int e = (N - 1) - clz ; /* exponent */ 36 long_double_bits fb; 37 fb.u.high.s.low = (e + 16383); /* exponent */ 38 fb.u.low.all = a << clz; /* mantissa */ 39 return fb.f; 40 } 41 42 #endif /* _ARCH_PPC */ 43
