mirror of
https://github.com/c64scene-ar/llvm-6502.git
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std::abs works just fine and we're already using it in many places. NFC intended. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231696 91177308-0d34-0410-b5e6-96231b3b80d8
635 lines
19 KiB
C++
635 lines
19 KiB
C++
//===-- llvm/Support/MathExtras.h - Useful math functions -------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains some functions that are useful for math stuff.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_MATHEXTRAS_H
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#define LLVM_SUPPORT_MATHEXTRAS_H
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/SwapByteOrder.h"
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#include <cassert>
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#include <cstring>
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#include <type_traits>
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#ifdef _MSC_VER
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#include <intrin.h>
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#endif
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namespace llvm {
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/// \brief The behavior an operation has on an input of 0.
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enum ZeroBehavior {
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/// \brief The returned value is undefined.
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ZB_Undefined,
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/// \brief The returned value is numeric_limits<T>::max()
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ZB_Max,
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/// \brief The returned value is numeric_limits<T>::digits
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ZB_Width
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};
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namespace detail {
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template <typename T, std::size_t SizeOfT> struct TrailingZerosCounter {
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static std::size_t count(T Val, ZeroBehavior) {
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if (!Val)
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return std::numeric_limits<T>::digits;
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if (Val & 0x1)
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return 0;
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// Bisection method.
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std::size_t ZeroBits = 0;
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T Shift = std::numeric_limits<T>::digits >> 1;
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T Mask = std::numeric_limits<T>::max() >> Shift;
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while (Shift) {
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if ((Val & Mask) == 0) {
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Val >>= Shift;
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ZeroBits |= Shift;
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}
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Shift >>= 1;
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Mask >>= Shift;
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}
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return ZeroBits;
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}
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};
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#if __GNUC__ >= 4 || _MSC_VER
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template <typename T> struct TrailingZerosCounter<T, 4> {
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static std::size_t count(T Val, ZeroBehavior ZB) {
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if (ZB != ZB_Undefined && Val == 0)
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return 32;
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#if __has_builtin(__builtin_ctz) || LLVM_GNUC_PREREQ(4, 0, 0)
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return __builtin_ctz(Val);
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#elif _MSC_VER
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unsigned long Index;
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_BitScanForward(&Index, Val);
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return Index;
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#endif
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}
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};
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#if !defined(_MSC_VER) || defined(_M_X64)
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template <typename T> struct TrailingZerosCounter<T, 8> {
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static std::size_t count(T Val, ZeroBehavior ZB) {
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if (ZB != ZB_Undefined && Val == 0)
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return 64;
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#if __has_builtin(__builtin_ctzll) || LLVM_GNUC_PREREQ(4, 0, 0)
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return __builtin_ctzll(Val);
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#elif _MSC_VER
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unsigned long Index;
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_BitScanForward64(&Index, Val);
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return Index;
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#endif
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}
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};
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#endif
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#endif
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} // namespace detail
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/// \brief Count number of 0's from the least significant bit to the most
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/// stopping at the first 1.
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///
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/// Only unsigned integral types are allowed.
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///
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/// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are
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/// valid arguments.
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template <typename T>
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std::size_t countTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
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static_assert(std::numeric_limits<T>::is_integer &&
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!std::numeric_limits<T>::is_signed,
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"Only unsigned integral types are allowed.");
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return detail::TrailingZerosCounter<T, sizeof(T)>::count(Val, ZB);
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}
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namespace detail {
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template <typename T, std::size_t SizeOfT> struct LeadingZerosCounter {
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static std::size_t count(T Val, ZeroBehavior) {
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if (!Val)
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return std::numeric_limits<T>::digits;
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// Bisection method.
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std::size_t ZeroBits = 0;
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for (T Shift = std::numeric_limits<T>::digits >> 1; Shift; Shift >>= 1) {
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T Tmp = Val >> Shift;
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if (Tmp)
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Val = Tmp;
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else
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ZeroBits |= Shift;
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}
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return ZeroBits;
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}
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};
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#if __GNUC__ >= 4 || _MSC_VER
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template <typename T> struct LeadingZerosCounter<T, 4> {
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static std::size_t count(T Val, ZeroBehavior ZB) {
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if (ZB != ZB_Undefined && Val == 0)
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return 32;
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#if __has_builtin(__builtin_clz) || LLVM_GNUC_PREREQ(4, 0, 0)
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return __builtin_clz(Val);
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#elif _MSC_VER
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unsigned long Index;
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_BitScanReverse(&Index, Val);
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return Index ^ 31;
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#endif
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}
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};
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#if !defined(_MSC_VER) || defined(_M_X64)
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template <typename T> struct LeadingZerosCounter<T, 8> {
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static std::size_t count(T Val, ZeroBehavior ZB) {
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if (ZB != ZB_Undefined && Val == 0)
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return 64;
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#if __has_builtin(__builtin_clzll) || LLVM_GNUC_PREREQ(4, 0, 0)
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return __builtin_clzll(Val);
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#elif _MSC_VER
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unsigned long Index;
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_BitScanReverse64(&Index, Val);
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return Index ^ 63;
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#endif
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}
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};
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#endif
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#endif
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} // namespace detail
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/// \brief Count number of 0's from the most significant bit to the least
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/// stopping at the first 1.
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///
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/// Only unsigned integral types are allowed.
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///
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/// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are
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/// valid arguments.
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template <typename T>
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std::size_t countLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
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static_assert(std::numeric_limits<T>::is_integer &&
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!std::numeric_limits<T>::is_signed,
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"Only unsigned integral types are allowed.");
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return detail::LeadingZerosCounter<T, sizeof(T)>::count(Val, ZB);
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}
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/// \brief Get the index of the first set bit starting from the least
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/// significant bit.
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///
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/// Only unsigned integral types are allowed.
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///
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/// \param ZB the behavior on an input of 0. Only ZB_Max and ZB_Undefined are
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/// valid arguments.
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template <typename T> T findFirstSet(T Val, ZeroBehavior ZB = ZB_Max) {
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if (ZB == ZB_Max && Val == 0)
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return std::numeric_limits<T>::max();
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return countTrailingZeros(Val, ZB_Undefined);
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}
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/// \brief Get the index of the last set bit starting from the least
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/// significant bit.
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///
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/// Only unsigned integral types are allowed.
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///
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/// \param ZB the behavior on an input of 0. Only ZB_Max and ZB_Undefined are
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/// valid arguments.
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template <typename T> T findLastSet(T Val, ZeroBehavior ZB = ZB_Max) {
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if (ZB == ZB_Max && Val == 0)
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return std::numeric_limits<T>::max();
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// Use ^ instead of - because both gcc and llvm can remove the associated ^
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// in the __builtin_clz intrinsic on x86.
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return countLeadingZeros(Val, ZB_Undefined) ^
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(std::numeric_limits<T>::digits - 1);
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}
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/// \brief Macro compressed bit reversal table for 256 bits.
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///
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/// http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable
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static const unsigned char BitReverseTable256[256] = {
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#define R2(n) n, n + 2 * 64, n + 1 * 64, n + 3 * 64
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#define R4(n) R2(n), R2(n + 2 * 16), R2(n + 1 * 16), R2(n + 3 * 16)
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#define R6(n) R4(n), R4(n + 2 * 4), R4(n + 1 * 4), R4(n + 3 * 4)
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R6(0), R6(2), R6(1), R6(3)
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#undef R2
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#undef R4
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#undef R6
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};
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/// \brief Reverse the bits in \p Val.
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template <typename T>
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T reverseBits(T Val) {
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unsigned char in[sizeof(Val)];
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unsigned char out[sizeof(Val)];
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std::memcpy(in, &Val, sizeof(Val));
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for (unsigned i = 0; i < sizeof(Val); ++i)
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out[(sizeof(Val) - i) - 1] = BitReverseTable256[in[i]];
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std::memcpy(&Val, out, sizeof(Val));
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return Val;
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}
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// NOTE: The following support functions use the _32/_64 extensions instead of
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// type overloading so that signed and unsigned integers can be used without
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// ambiguity.
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/// Hi_32 - This function returns the high 32 bits of a 64 bit value.
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inline uint32_t Hi_32(uint64_t Value) {
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return static_cast<uint32_t>(Value >> 32);
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}
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/// Lo_32 - This function returns the low 32 bits of a 64 bit value.
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inline uint32_t Lo_32(uint64_t Value) {
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return static_cast<uint32_t>(Value);
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}
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/// Make_64 - This functions makes a 64-bit integer from a high / low pair of
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/// 32-bit integers.
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inline uint64_t Make_64(uint32_t High, uint32_t Low) {
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return ((uint64_t)High << 32) | (uint64_t)Low;
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}
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/// isInt - Checks if an integer fits into the given bit width.
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template<unsigned N>
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inline bool isInt(int64_t x) {
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return N >= 64 || (-(INT64_C(1)<<(N-1)) <= x && x < (INT64_C(1)<<(N-1)));
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}
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// Template specializations to get better code for common cases.
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template<>
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inline bool isInt<8>(int64_t x) {
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return static_cast<int8_t>(x) == x;
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}
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template<>
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inline bool isInt<16>(int64_t x) {
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return static_cast<int16_t>(x) == x;
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}
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template<>
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inline bool isInt<32>(int64_t x) {
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return static_cast<int32_t>(x) == x;
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}
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/// isShiftedInt<N,S> - Checks if a signed integer is an N bit number shifted
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/// left by S.
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template<unsigned N, unsigned S>
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inline bool isShiftedInt(int64_t x) {
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return isInt<N+S>(x) && (x % (1<<S) == 0);
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}
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/// isUInt - Checks if an unsigned integer fits into the given bit width.
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template<unsigned N>
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inline bool isUInt(uint64_t x) {
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return N >= 64 || x < (UINT64_C(1)<<(N));
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}
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// Template specializations to get better code for common cases.
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template<>
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inline bool isUInt<8>(uint64_t x) {
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return static_cast<uint8_t>(x) == x;
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}
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template<>
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inline bool isUInt<16>(uint64_t x) {
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return static_cast<uint16_t>(x) == x;
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}
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template<>
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inline bool isUInt<32>(uint64_t x) {
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return static_cast<uint32_t>(x) == x;
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}
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/// isShiftedUInt<N,S> - Checks if a unsigned integer is an N bit number shifted
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/// left by S.
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template<unsigned N, unsigned S>
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inline bool isShiftedUInt(uint64_t x) {
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return isUInt<N+S>(x) && (x % (1<<S) == 0);
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}
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/// isUIntN - Checks if an unsigned integer fits into the given (dynamic)
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/// bit width.
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inline bool isUIntN(unsigned N, uint64_t x) {
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return x == (x & (~0ULL >> (64 - N)));
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}
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/// isIntN - Checks if an signed integer fits into the given (dynamic)
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/// bit width.
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inline bool isIntN(unsigned N, int64_t x) {
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return N >= 64 || (-(INT64_C(1)<<(N-1)) <= x && x < (INT64_C(1)<<(N-1)));
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}
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/// isMask_32 - This function returns true if the argument is a sequence of ones
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/// starting at the least significant bit with the remainder zero (32 bit
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/// version). Ex. isMask_32(0x0000FFFFU) == true.
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inline bool isMask_32(uint32_t Value) {
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return Value && ((Value + 1) & Value) == 0;
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}
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/// isMask_64 - This function returns true if the argument is a sequence of ones
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/// starting at the least significant bit with the remainder zero (64 bit
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/// version).
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inline bool isMask_64(uint64_t Value) {
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return Value && ((Value + 1) & Value) == 0;
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}
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/// isShiftedMask_32 - This function returns true if the argument contains a
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/// sequence of ones with the remainder zero (32 bit version.)
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/// Ex. isShiftedMask_32(0x0000FF00U) == true.
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inline bool isShiftedMask_32(uint32_t Value) {
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return isMask_32((Value - 1) | Value);
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}
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/// isShiftedMask_64 - This function returns true if the argument contains a
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/// sequence of ones with the remainder zero (64 bit version.)
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inline bool isShiftedMask_64(uint64_t Value) {
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return isMask_64((Value - 1) | Value);
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}
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/// isPowerOf2_32 - This function returns true if the argument is a power of
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/// two > 0. Ex. isPowerOf2_32(0x00100000U) == true (32 bit edition.)
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inline bool isPowerOf2_32(uint32_t Value) {
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return Value && !(Value & (Value - 1));
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}
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/// isPowerOf2_64 - This function returns true if the argument is a power of two
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/// > 0 (64 bit edition.)
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inline bool isPowerOf2_64(uint64_t Value) {
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return Value && !(Value & (Value - int64_t(1L)));
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}
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/// ByteSwap_16 - This function returns a byte-swapped representation of the
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/// 16-bit argument, Value.
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inline uint16_t ByteSwap_16(uint16_t Value) {
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return sys::SwapByteOrder_16(Value);
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}
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/// ByteSwap_32 - This function returns a byte-swapped representation of the
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/// 32-bit argument, Value.
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inline uint32_t ByteSwap_32(uint32_t Value) {
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return sys::SwapByteOrder_32(Value);
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}
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/// ByteSwap_64 - This function returns a byte-swapped representation of the
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/// 64-bit argument, Value.
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inline uint64_t ByteSwap_64(uint64_t Value) {
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return sys::SwapByteOrder_64(Value);
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}
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/// \brief Count the number of ones from the most significant bit to the first
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/// zero bit.
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///
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/// Ex. CountLeadingOnes(0xFF0FFF00) == 8.
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/// Only unsigned integral types are allowed.
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///
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/// \param ZB the behavior on an input of all ones. Only ZB_Width and
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/// ZB_Undefined are valid arguments.
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template <typename T>
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std::size_t countLeadingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
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static_assert(std::numeric_limits<T>::is_integer &&
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!std::numeric_limits<T>::is_signed,
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"Only unsigned integral types are allowed.");
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return countLeadingZeros(~Value, ZB);
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}
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/// \brief Count the number of ones from the least significant bit to the first
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/// zero bit.
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///
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/// Ex. countTrailingOnes(0x00FF00FF) == 8.
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/// Only unsigned integral types are allowed.
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///
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/// \param ZB the behavior on an input of all ones. Only ZB_Width and
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/// ZB_Undefined are valid arguments.
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template <typename T>
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std::size_t countTrailingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
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static_assert(std::numeric_limits<T>::is_integer &&
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!std::numeric_limits<T>::is_signed,
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"Only unsigned integral types are allowed.");
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return countTrailingZeros(~Value, ZB);
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}
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namespace detail {
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template <typename T, std::size_t SizeOfT> struct PopulationCounter {
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static unsigned count(T Value) {
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// Generic version, forward to 32 bits.
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static_assert(SizeOfT <= 4, "Not implemented!");
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#if __GNUC__ >= 4
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return __builtin_popcount(Value);
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#else
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uint32_t v = Value;
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v = v - ((v >> 1) & 0x55555555);
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v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
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return ((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24;
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#endif
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}
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};
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template <typename T> struct PopulationCounter<T, 8> {
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static unsigned count(T Value) {
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#if __GNUC__ >= 4
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return __builtin_popcountll(Value);
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#else
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uint64_t v = Value;
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v = v - ((v >> 1) & 0x5555555555555555ULL);
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v = (v & 0x3333333333333333ULL) + ((v >> 2) & 0x3333333333333333ULL);
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v = (v + (v >> 4)) & 0x0F0F0F0F0F0F0F0FULL;
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return unsigned((uint64_t)(v * 0x0101010101010101ULL) >> 56);
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#endif
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}
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};
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} // namespace detail
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/// \brief Count the number of set bits in a value.
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/// Ex. countPopulation(0xF000F000) = 8
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/// Returns 0 if the word is zero.
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template <typename T>
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inline unsigned countPopulation(T Value) {
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static_assert(std::numeric_limits<T>::is_integer &&
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!std::numeric_limits<T>::is_signed,
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"Only unsigned integral types are allowed.");
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return detail::PopulationCounter<T, sizeof(T)>::count(Value);
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}
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/// Log2_32 - This function returns the floor log base 2 of the specified value,
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/// -1 if the value is zero. (32 bit edition.)
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/// Ex. Log2_32(32) == 5, Log2_32(1) == 0, Log2_32(0) == -1, Log2_32(6) == 2
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inline unsigned Log2_32(uint32_t Value) {
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return 31 - countLeadingZeros(Value);
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}
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/// Log2_64 - This function returns the floor log base 2 of the specified value,
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/// -1 if the value is zero. (64 bit edition.)
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inline unsigned Log2_64(uint64_t Value) {
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return 63 - countLeadingZeros(Value);
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}
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/// Log2_32_Ceil - This function returns the ceil log base 2 of the specified
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/// value, 32 if the value is zero. (32 bit edition).
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/// Ex. Log2_32_Ceil(32) == 5, Log2_32_Ceil(1) == 0, Log2_32_Ceil(6) == 3
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inline unsigned Log2_32_Ceil(uint32_t Value) {
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return 32 - countLeadingZeros(Value - 1);
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|
}
|
|
|
|
/// Log2_64_Ceil - This function returns the ceil log base 2 of the specified
|
|
/// value, 64 if the value is zero. (64 bit edition.)
|
|
inline unsigned Log2_64_Ceil(uint64_t Value) {
|
|
return 64 - countLeadingZeros(Value - 1);
|
|
}
|
|
|
|
/// GreatestCommonDivisor64 - Return the greatest common divisor of the two
|
|
/// values using Euclid's algorithm.
|
|
inline uint64_t GreatestCommonDivisor64(uint64_t A, uint64_t B) {
|
|
while (B) {
|
|
uint64_t T = B;
|
|
B = A % B;
|
|
A = T;
|
|
}
|
|
return A;
|
|
}
|
|
|
|
/// BitsToDouble - This function takes a 64-bit integer and returns the bit
|
|
/// equivalent double.
|
|
inline double BitsToDouble(uint64_t Bits) {
|
|
union {
|
|
uint64_t L;
|
|
double D;
|
|
} T;
|
|
T.L = Bits;
|
|
return T.D;
|
|
}
|
|
|
|
/// BitsToFloat - This function takes a 32-bit integer and returns the bit
|
|
/// equivalent float.
|
|
inline float BitsToFloat(uint32_t Bits) {
|
|
union {
|
|
uint32_t I;
|
|
float F;
|
|
} T;
|
|
T.I = Bits;
|
|
return T.F;
|
|
}
|
|
|
|
/// DoubleToBits - This function takes a double and returns the bit
|
|
/// equivalent 64-bit integer. Note that copying doubles around
|
|
/// changes the bits of NaNs on some hosts, notably x86, so this
|
|
/// routine cannot be used if these bits are needed.
|
|
inline uint64_t DoubleToBits(double Double) {
|
|
union {
|
|
uint64_t L;
|
|
double D;
|
|
} T;
|
|
T.D = Double;
|
|
return T.L;
|
|
}
|
|
|
|
/// FloatToBits - This function takes a float and returns the bit
|
|
/// equivalent 32-bit integer. Note that copying floats around
|
|
/// changes the bits of NaNs on some hosts, notably x86, so this
|
|
/// routine cannot be used if these bits are needed.
|
|
inline uint32_t FloatToBits(float Float) {
|
|
union {
|
|
uint32_t I;
|
|
float F;
|
|
} T;
|
|
T.F = Float;
|
|
return T.I;
|
|
}
|
|
|
|
/// MinAlign - A and B are either alignments or offsets. Return the minimum
|
|
/// alignment that may be assumed after adding the two together.
|
|
inline uint64_t MinAlign(uint64_t A, uint64_t B) {
|
|
// The largest power of 2 that divides both A and B.
|
|
//
|
|
// Replace "-Value" by "1+~Value" in the following commented code to avoid
|
|
// MSVC warning C4146
|
|
// return (A | B) & -(A | B);
|
|
return (A | B) & (1 + ~(A | B));
|
|
}
|
|
|
|
/// \brief Aligns \c Addr to \c Alignment bytes, rounding up.
|
|
///
|
|
/// Alignment should be a power of two. This method rounds up, so
|
|
/// alignAddr(7, 4) == 8 and alignAddr(8, 4) == 8.
|
|
inline uintptr_t alignAddr(void *Addr, size_t Alignment) {
|
|
assert(Alignment && isPowerOf2_64((uint64_t)Alignment) &&
|
|
"Alignment is not a power of two!");
|
|
|
|
assert((uintptr_t)Addr + Alignment - 1 >= (uintptr_t)Addr);
|
|
|
|
return (((uintptr_t)Addr + Alignment - 1) & ~(uintptr_t)(Alignment - 1));
|
|
}
|
|
|
|
/// \brief Returns the necessary adjustment for aligning \c Ptr to \c Alignment
|
|
/// bytes, rounding up.
|
|
inline size_t alignmentAdjustment(void *Ptr, size_t Alignment) {
|
|
return alignAddr(Ptr, Alignment) - (uintptr_t)Ptr;
|
|
}
|
|
|
|
/// NextPowerOf2 - Returns the next power of two (in 64-bits)
|
|
/// that is strictly greater than A. Returns zero on overflow.
|
|
inline uint64_t NextPowerOf2(uint64_t A) {
|
|
A |= (A >> 1);
|
|
A |= (A >> 2);
|
|
A |= (A >> 4);
|
|
A |= (A >> 8);
|
|
A |= (A >> 16);
|
|
A |= (A >> 32);
|
|
return A + 1;
|
|
}
|
|
|
|
/// Returns the power of two which is less than or equal to the given value.
|
|
/// Essentially, it is a floor operation across the domain of powers of two.
|
|
inline uint64_t PowerOf2Floor(uint64_t A) {
|
|
if (!A) return 0;
|
|
return 1ull << (63 - countLeadingZeros(A, ZB_Undefined));
|
|
}
|
|
|
|
/// Returns the next integer (mod 2**64) that is greater than or equal to
|
|
/// \p Value and is a multiple of \p Align. \p Align must be non-zero.
|
|
///
|
|
/// Examples:
|
|
/// \code
|
|
/// RoundUpToAlignment(5, 8) = 8
|
|
/// RoundUpToAlignment(17, 8) = 24
|
|
/// RoundUpToAlignment(~0LL, 8) = 0
|
|
/// RoundUpToAlignment(321, 255) = 510
|
|
/// \endcode
|
|
inline uint64_t RoundUpToAlignment(uint64_t Value, uint64_t Align) {
|
|
return (Value + Align - 1) / Align * Align;
|
|
}
|
|
|
|
/// Returns the offset to the next integer (mod 2**64) that is greater than
|
|
/// or equal to \p Value and is a multiple of \p Align. \p Align must be
|
|
/// non-zero.
|
|
inline uint64_t OffsetToAlignment(uint64_t Value, uint64_t Align) {
|
|
return RoundUpToAlignment(Value, Align) - Value;
|
|
}
|
|
|
|
/// SignExtend32 - Sign extend B-bit number x to 32-bit int.
|
|
/// Usage int32_t r = SignExtend32<5>(x);
|
|
template <unsigned B> inline int32_t SignExtend32(uint32_t x) {
|
|
return int32_t(x << (32 - B)) >> (32 - B);
|
|
}
|
|
|
|
/// \brief Sign extend number in the bottom B bits of X to a 32-bit int.
|
|
/// Requires 0 < B <= 32.
|
|
inline int32_t SignExtend32(uint32_t X, unsigned B) {
|
|
return int32_t(X << (32 - B)) >> (32 - B);
|
|
}
|
|
|
|
/// SignExtend64 - Sign extend B-bit number x to 64-bit int.
|
|
/// Usage int64_t r = SignExtend64<5>(x);
|
|
template <unsigned B> inline int64_t SignExtend64(uint64_t x) {
|
|
return int64_t(x << (64 - B)) >> (64 - B);
|
|
}
|
|
|
|
/// \brief Sign extend number in the bottom B bits of X to a 64-bit int.
|
|
/// Requires 0 < B <= 64.
|
|
inline int64_t SignExtend64(uint64_t X, unsigned B) {
|
|
return int64_t(X << (64 - B)) >> (64 - B);
|
|
}
|
|
|
|
extern const float huge_valf;
|
|
} // End llvm namespace
|
|
|
|
#endif
|