| //===- FixedPoint.cpp - Fixed point constant handling -----------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| /// \file |
| /// Defines the implementation for the fixed point number interface. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Basic/FixedPoint.h" |
| |
| namespace clang { |
| |
| APFixedPoint APFixedPoint::convert(const FixedPointSemantics &DstSema) const { |
| llvm::APSInt NewVal = Val; |
| unsigned DstWidth = DstSema.getWidth(); |
| unsigned DstScale = DstSema.getScale(); |
| bool Upscaling = DstScale > getScale(); |
| |
| if (Upscaling) { |
| NewVal = NewVal.extend(NewVal.getBitWidth() + DstScale - getScale()); |
| NewVal <<= (DstScale - getScale()); |
| } else { |
| NewVal >>= (getScale() - DstScale); |
| } |
| |
| if (DstSema.isSaturated()) { |
| auto Mask = llvm::APInt::getBitsSetFrom( |
| NewVal.getBitWidth(), |
| std::min(DstScale + DstSema.getIntegralBits(), NewVal.getBitWidth())); |
| llvm::APInt Masked(NewVal & Mask); |
| |
| // Change in the bits above the sign |
| if (!(Masked == Mask || Masked == 0)) |
| NewVal = NewVal.isNegative() ? Mask : ~Mask; |
| |
| if (!DstSema.isSigned() && NewVal.isNegative()) |
| NewVal = 0; |
| } |
| |
| NewVal = NewVal.extOrTrunc(DstWidth); |
| NewVal.setIsSigned(DstSema.isSigned()); |
| return APFixedPoint(NewVal, DstSema); |
| } |
| |
| int APFixedPoint::compare(const APFixedPoint &Other) const { |
| llvm::APSInt ThisVal = getValue(); |
| llvm::APSInt OtherVal = Other.getValue(); |
| bool ThisSigned = Val.isSigned(); |
| bool OtherSigned = OtherVal.isSigned(); |
| unsigned OtherScale = Other.getScale(); |
| unsigned OtherWidth = OtherVal.getBitWidth(); |
| |
| unsigned CommonWidth = std::max(Val.getBitWidth(), OtherWidth); |
| |
| // Prevent overflow in the event the widths are the same but the scales differ |
| CommonWidth += getScale() >= OtherScale ? getScale() - OtherScale |
| : OtherScale - getScale(); |
| |
| ThisVal = ThisVal.extOrTrunc(CommonWidth); |
| OtherVal = OtherVal.extOrTrunc(CommonWidth); |
| |
| unsigned CommonScale = std::max(getScale(), OtherScale); |
| ThisVal = ThisVal.shl(CommonScale - getScale()); |
| OtherVal = OtherVal.shl(CommonScale - OtherScale); |
| |
| if (ThisSigned && OtherSigned) { |
| if (ThisVal.sgt(OtherVal)) |
| return 1; |
| else if (ThisVal.slt(OtherVal)) |
| return -1; |
| } else if (!ThisSigned && !OtherSigned) { |
| if (ThisVal.ugt(OtherVal)) |
| return 1; |
| else if (ThisVal.ult(OtherVal)) |
| return -1; |
| } else if (ThisSigned && !OtherSigned) { |
| if (ThisVal.isSignBitSet()) |
| return -1; |
| else if (ThisVal.ugt(OtherVal)) |
| return 1; |
| else if (ThisVal.ult(OtherVal)) |
| return -1; |
| } else { |
| // !ThisSigned && OtherSigned |
| if (OtherVal.isSignBitSet()) |
| return 1; |
| else if (ThisVal.ugt(OtherVal)) |
| return 1; |
| else if (ThisVal.ult(OtherVal)) |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| APFixedPoint APFixedPoint::getMax(const FixedPointSemantics &Sema) { |
| bool IsUnsigned = !Sema.isSigned(); |
| auto Val = llvm::APSInt::getMaxValue(Sema.getWidth(), IsUnsigned); |
| if (IsUnsigned && Sema.hasUnsignedPadding()) |
| Val = Val.lshr(1); |
| return APFixedPoint(Val, Sema); |
| } |
| |
| APFixedPoint APFixedPoint::getMin(const FixedPointSemantics &Sema) { |
| auto Val = llvm::APSInt::getMinValue(Sema.getWidth(), !Sema.isSigned()); |
| return APFixedPoint(Val, Sema); |
| } |
| |
| } // namespace clang |