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102 lines
2.8 KiB
C++
102 lines
2.8 KiB
C++
//===-- ctfloat.cpp -------------------------------------------------------===//
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//
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// LDC – the LLVM D compiler
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//
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// This file is distributed under the BSD-style LDC license. See the LICENSE
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// file for details.
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//
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//===----------------------------------------------------------------------===//
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#include "ctfloat.h"
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#include "gen/llvm.h"
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using llvm::APFloat;
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#if LDC_LLVM_VER >= 400
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#define AP_SEMANTICS_PARENS ()
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#else
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#define AP_SEMANTICS_PARENS
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#endif
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namespace {
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const llvm::fltSemantics *apSemantics = nullptr;
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constexpr unsigned numUint64Parts = (sizeof(real_t) + 7) / 8;
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union CTFloatUnion {
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real_t fp;
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uint64_t bits[numUint64Parts];
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};
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APFloat parseLiteral(const llvm::fltSemantics &semantics, const char *literal,
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bool *isOutOfRange = nullptr) {
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APFloat ap(semantics, APFloat::uninitialized);
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const auto r = ap.convertFromString(literal, APFloat::rmNearestTiesToEven);
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if (isOutOfRange) {
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*isOutOfRange = (r & (APFloat::opOverflow | APFloat::opUnderflow)) != 0;
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}
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return ap;
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}
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} // anonymous namespace
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////////////////////////////////////////////////////////////////////////////////
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void CTFloat::_init() {
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static_assert(sizeof(real_t) >= 8, "real_t < 64 bits?");
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if (sizeof(real_t) == 8) {
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apSemantics = &(APFloat::IEEEdouble AP_SEMANTICS_PARENS);
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return;
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}
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#if __i386__ || __x86_64__
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apSemantics = &(APFloat::x87DoubleExtended AP_SEMANTICS_PARENS);
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#elif __aarch64__
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apSemantics = &(APFloat::IEEEquad AP_SEMANTICS_PARENS);
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#elif __ppc__ || __ppc64__
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apSemantics = &(APFloat::PPCDoubleDouble AP_SEMANTICS_PARENS);
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#else
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llvm_unreachable("Unknown host real_t type for compile-time reals");
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#endif
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}
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////////////////////////////////////////////////////////////////////////////////
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void CTFloat::toAPFloat(const real_t src, APFloat &dst) {
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if (sizeof(real_t) == 8) {
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dst = APFloat(static_cast<double>(src));
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return;
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}
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CTFloatUnion u;
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u.fp = src;
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const unsigned sizeInBits = APFloat::getSizeInBits(*apSemantics);
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const APInt bits = APInt(sizeInBits, numUint64Parts, u.bits);
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dst = APFloat(*apSemantics, bits);
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}
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////////////////////////////////////////////////////////////////////////////////
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real_t CTFloat::parse(const char *literal, bool *isOutOfRange) {
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const APFloat ap = parseLiteral(*apSemantics, literal, isOutOfRange);
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const APInt bits = ap.bitcastToAPInt();
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CTFloatUnion u;
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memcpy(u.bits, bits.getRawData(), bits.getBitWidth() / 8);
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return u.fp;
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}
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bool CTFloat::isFloat32LiteralOutOfRange(const char *literal) {
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bool isOutOfRange;
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parseLiteral(APFloat::IEEEsingle AP_SEMANTICS_PARENS, literal, &isOutOfRange);
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return isOutOfRange;
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}
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bool CTFloat::isFloat64LiteralOutOfRange(const char *literal) {
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bool isOutOfRange;
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parseLiteral(APFloat::IEEEdouble AP_SEMANTICS_PARENS, literal, &isOutOfRange);
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return isOutOfRange;
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}
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