powidf2.c revision 2d1fdb26e458c4ddc04155c1d421bced3ba90cd0
1e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson/* ===-- powidf2.cpp - Implement __powidf2 ---------------------------------=== 2e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson * 3e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson * The LLVM Compiler Infrastructure 4e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson * 5e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson * This file is dual licensed under the MIT and the University of Illinois Open 6e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson * Source Licenses. See LICENSE.TXT for details. 7e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson * 8e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson * ===----------------------------------------------------------------------=== 9e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson * 10e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson * This file implements __powidf2 for the compiler_rt library. 11e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson * 12e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson * ===----------------------------------------------------------------------=== 13e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson */ 14e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson 15e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson#include "int_lib.h" 16e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson 17e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson/* Returns: a ^ b */ 18e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson 19e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian ParkinsonCOMPILER_RT_ABI double 20e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson__powidf2(double a, si_int b) 21e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson{ 22e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson const int recip = b < 0; 23e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson double r = 1; 24e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson while (1) 25e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson { 26e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson if (b & 1) 27e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson r *= a; 28e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson b /= 2; 29e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson if (b == 0) 30e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson break; 31e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson a *= a; 32e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson } 33e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson return recip ? 1/r : r; 34e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson} 35e0ae5d7e87b1dd6e789803c1b9615a84bd7488b7Ian Parkinson