From ca9211ecdede9bdedb812b2243a4abdb8dacd1b9 Mon Sep 17 00:00:00 2001 From: Dimitry Andric Date: Wed, 7 Jan 2015 19:55:37 +0000 Subject: Import compiler-rt trunk r224034. https://llvm.org/svn/llvm-project/compiler-rt/trunk@224034 --- lib/builtins/floatunsidf.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 lib/builtins/floatunsidf.c (limited to 'lib/builtins/floatunsidf.c') diff --git a/lib/builtins/floatunsidf.c b/lib/builtins/floatunsidf.c new file mode 100644 index 000000000000..445e18041c48 --- /dev/null +++ b/lib/builtins/floatunsidf.c @@ -0,0 +1,42 @@ +//===-- lib/floatunsidf.c - uint -> double-precision conversion ---*- C -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is dual licensed under the MIT and the University of Illinois Open +// Source Licenses. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements unsigned integer to double-precision conversion for the +// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even +// mode. +// +//===----------------------------------------------------------------------===// + +#define DOUBLE_PRECISION +#include "fp_lib.h" + +#include "int_lib.h" + +ARM_EABI_FNALIAS(ui2d, floatunsidf) + +COMPILER_RT_ABI fp_t +__floatunsidf(unsigned int a) { + + const int aWidth = sizeof a * CHAR_BIT; + + // Handle zero as a special case to protect clz + if (a == 0) return fromRep(0); + + // Exponent of (fp_t)a is the width of abs(a). + const int exponent = (aWidth - 1) - __builtin_clz(a); + rep_t result; + + // Shift a into the significand field and clear the implicit bit. + const int shift = significandBits - exponent; + result = (rep_t)a << shift ^ implicitBit; + + // Insert the exponent + result += (rep_t)(exponent + exponentBias) << significandBits; + return fromRep(result); +} -- cgit v1.2.3