| 1 | //===-- lib/floatsidf.c - integer -> double-precision conversion --*- C -*-===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // |
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| 9 | // This file implements integer to double-precision conversion for the |
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| 10 | // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even |
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| 11 | // mode. |
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| 12 | // |
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| 13 | //===----------------------------------------------------------------------===// |
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| 14 | |
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| 15 | #define DOUBLE_PRECISION |
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| 16 | #include "fp_lib.h" |
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| 17 | |
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| 18 | #include "int_lib.h" |
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| 19 | |
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| 20 | COMPILER_RT_ABI fp_t __floatsidf(si_int a) { |
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| 21 | |
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| 22 | const int aWidth = sizeof a * CHAR_BIT; |
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| 23 | |
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| 24 | // Handle zero as a special case to protect clz |
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| 25 | if (a == 0) |
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| 26 | return fromRep(x: 0); |
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| 27 | |
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| 28 | // All other cases begin by extracting the sign and absolute value of a |
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| 29 | rep_t sign = 0; |
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| 30 | su_int aAbs = (su_int)a; |
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| 31 | if (a < 0) { |
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| 32 | sign = signBit; |
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| 33 | aAbs = -aAbs; |
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| 34 | } |
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| 35 | |
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| 36 | // Exponent of (fp_t)a is the width of abs(a). |
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| 37 | const int exponent = (aWidth - 1) - clzsi(aAbs); |
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| 38 | rep_t result; |
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| 39 | |
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| 40 | // Shift a into the significand field and clear the implicit bit. Extra |
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| 41 | // cast to unsigned int is necessary to get the correct behavior for |
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| 42 | // the input INT_MIN. |
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| 43 | const int shift = significandBits - exponent; |
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| 44 | result = (rep_t)aAbs << shift ^ implicitBit; |
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| 45 | |
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| 46 | // Insert the exponent |
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| 47 | result += (rep_t)(exponent + exponentBias) << significandBits; |
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| 48 | // Insert the sign bit and return |
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| 49 | return fromRep(x: result | sign); |
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| 50 | } |
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| 51 | |
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| 52 | #if defined(__ARM_EABI__) |
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| 53 | #if defined(COMPILER_RT_ARMHF_TARGET) |
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| 54 | AEABI_RTABI fp_t __aeabi_i2d(si_int a) { return __floatsidf(a); } |
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| 55 | #else |
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| 56 | COMPILER_RT_ALIAS(__floatsidf, __aeabi_i2d) |
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| 57 | #endif |
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| 58 | #endif |
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| 59 | |
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