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//===-- lib/floatsisf.c - integer -> single-precision conversion --*- C -*-===// |
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// |
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// The LLVM Compiler Infrastructure |
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// |
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// This file is dual licensed under the MIT and the University of Illinois Open |
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// Source Licenses. See LICENSE.TXT for details. |
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// |
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//===----------------------------------------------------------------------===// |
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// |
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// This file implements integer to single-precision conversion for the |
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// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even |
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// mode. |
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// |
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//===----------------------------------------------------------------------===// |
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#define SINGLE_PRECISION |
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#include "fp_lib.h" |
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#include "int_lib.h" |
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ARM_EABI_FNALIAS(i2f, floatsisf) |
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COMPILER_RT_ABI fp_t |
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__floatsisf(int a) { |
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const int aWidth = sizeof a * CHAR_BIT; |
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// Handle zero as a special case to protect clz |
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if (a == 0) |
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return fromRep(0); |
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// All other cases begin by extracting the sign and absolute value of a |
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rep_t sign = 0; |
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if (a < 0) { |
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sign = signBit; |
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a = -a; |
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} |
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// Exponent of (fp_t)a is the width of abs(a). |
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const int exponent = (aWidth - 1) - __builtin_clz(a); |
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rep_t result; |
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// Shift a into the significand field, rounding if it is a right-shift |
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if (exponent <= significandBits) { |
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const int shift = significandBits - exponent; |
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result = (rep_t)a << shift ^ implicitBit; |
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} else { |
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const int shift = exponent - significandBits; |
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result = (rep_t)a >> shift ^ implicitBit; |
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rep_t round = (rep_t)a << (typeWidth - shift); |
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if (round > signBit) result++; |
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if (round == signBit) result += result & 1; |
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} |
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// Insert the exponent |
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result += (rep_t)(exponent + exponentBias) << significandBits; |
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// Insert the sign bit and return |
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return fromRep(result | sign); |
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} |