mirror of
https://github.com/Ryujinx/Ryujinx.git
synced 2024-12-25 08:46:03 +00:00
173 lines
5.8 KiB
C#
173 lines
5.8 KiB
C#
|
using ARMeilleure.IntermediateRepresentation;
|
||
|
using System;
|
||
|
using System.Numerics;
|
||
|
|
||
|
namespace ARMeilleure.CodeGen.Arm64
|
||
|
{
|
||
|
static class CodeGenCommon
|
||
|
{
|
||
|
public const int TcAddressRegister = 8;
|
||
|
public const int ReservedRegister = 17;
|
||
|
|
||
|
public static bool ConstFitsOnSImm7(int value, int scale)
|
||
|
{
|
||
|
return (((value >> scale) << 25) >> (25 - scale)) == value;
|
||
|
}
|
||
|
|
||
|
public static bool ConstFitsOnSImm9(int value)
|
||
|
{
|
||
|
return ((value << 23) >> 23) == value;
|
||
|
}
|
||
|
|
||
|
public static bool ConstFitsOnUImm12(int value)
|
||
|
{
|
||
|
return (value & 0xfff) == value;
|
||
|
}
|
||
|
|
||
|
public static bool ConstFitsOnUImm12(int value, OperandType type)
|
||
|
{
|
||
|
int scale = Assembler.GetScaleForType(type);
|
||
|
return (((value >> scale) & 0xfff) << scale) == value;
|
||
|
}
|
||
|
|
||
|
public static bool TryEncodeBitMask(Operand operand, out int immN, out int immS, out int immR)
|
||
|
{
|
||
|
ulong value = operand.Value;
|
||
|
|
||
|
if (operand.Type == OperandType.I32)
|
||
|
{
|
||
|
value |= value << 32;
|
||
|
}
|
||
|
|
||
|
return TryEncodeBitMask(value, out immN, out immS, out immR);
|
||
|
}
|
||
|
|
||
|
public static bool TryEncodeBitMask(ulong value, out int immN, out int immS, out int immR)
|
||
|
{
|
||
|
// Some special values also can't be encoded:
|
||
|
// 0 can't be encoded because we need to subtract 1 from onesCount (which would became negative if 0).
|
||
|
// A value with all bits set can't be encoded because it is reserved according to the spec, because:
|
||
|
// Any value AND all ones will be equal itself, so it's effectively a no-op.
|
||
|
// Any value OR all ones will be equal all ones, so one can just use MOV.
|
||
|
// Any value XOR all ones will be equal its inverse, so one can just use MVN.
|
||
|
if (value == ulong.MaxValue)
|
||
|
{
|
||
|
immN = 0;
|
||
|
immS = 0;
|
||
|
immR = 0;
|
||
|
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
int bitLength = CountSequence(value);
|
||
|
|
||
|
if ((value >> bitLength) != 0)
|
||
|
{
|
||
|
bitLength += CountSequence(value >> bitLength);
|
||
|
}
|
||
|
|
||
|
int bitLengthLog2 = BitOperations.Log2((uint)bitLength);
|
||
|
int bitLengthPow2 = 1 << bitLengthLog2;
|
||
|
|
||
|
if (bitLengthPow2 < bitLength)
|
||
|
{
|
||
|
bitLengthLog2++;
|
||
|
bitLengthPow2 <<= 1;
|
||
|
}
|
||
|
|
||
|
int selectedESize = 64;
|
||
|
int repetitions = 1;
|
||
|
int onesCount = BitOperations.PopCount(value);
|
||
|
|
||
|
if (bitLengthPow2 < 64 && (value >> bitLengthPow2) != 0)
|
||
|
{
|
||
|
for (int eSizeLog2 = bitLengthLog2; eSizeLog2 < 6; eSizeLog2++)
|
||
|
{
|
||
|
bool match = true;
|
||
|
int eSize = 1 << eSizeLog2;
|
||
|
ulong mask = (1UL << eSize) - 1;
|
||
|
ulong eValue = value & mask;
|
||
|
|
||
|
for (int e = 1; e < 64 / eSize; e++)
|
||
|
{
|
||
|
if (((value >> (e * eSize)) & mask) != eValue)
|
||
|
{
|
||
|
match = false;
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if (match)
|
||
|
{
|
||
|
selectedESize = eSize;
|
||
|
repetitions = 64 / eSize;
|
||
|
onesCount = BitOperations.PopCount(eValue);
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// Find rotation. We have two cases, one where the highest bit is 0
|
||
|
// and one where it is 1.
|
||
|
// If it's 1, we just need to count the number of 1 bits on the MSB to find the right rotation.
|
||
|
// If it's 0, we just need to count the number of 0 bits on the LSB to find the left rotation,
|
||
|
// then we can convert it to the right rotation shift by subtracting the value from the element size.
|
||
|
int rotation;
|
||
|
long vHigh = (long)(value << (64 - selectedESize));
|
||
|
if (vHigh < 0)
|
||
|
{
|
||
|
rotation = BitOperations.LeadingZeroCount(~(ulong)vHigh);
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
rotation = (selectedESize - BitOperations.TrailingZeroCount(value)) & (selectedESize - 1);
|
||
|
}
|
||
|
|
||
|
// Reconstruct value and see if it matches. If not, we can't encode.
|
||
|
ulong reconstructed = onesCount == 64 ? ulong.MaxValue : RotateRight((1UL << onesCount) - 1, rotation, selectedESize);
|
||
|
|
||
|
for (int bit = 32; bit >= selectedESize; bit >>= 1)
|
||
|
{
|
||
|
reconstructed |= reconstructed << bit;
|
||
|
}
|
||
|
|
||
|
if (reconstructed != value || onesCount == 0)
|
||
|
{
|
||
|
immN = 0;
|
||
|
immS = 0;
|
||
|
immR = 0;
|
||
|
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
immR = rotation;
|
||
|
|
||
|
// immN indicates that there are no repetitions.
|
||
|
// The MSB of immS indicates the amount of repetitions, and the LSB the number of bits set.
|
||
|
if (repetitions == 1)
|
||
|
{
|
||
|
immN = 1;
|
||
|
immS = 0;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
immN = 0;
|
||
|
immS = (0xf80 >> BitOperations.Log2((uint)repetitions)) & 0x3f;
|
||
|
}
|
||
|
|
||
|
immS |= onesCount - 1;
|
||
|
|
||
|
return true;
|
||
|
}
|
||
|
|
||
|
private static int CountSequence(ulong value)
|
||
|
{
|
||
|
return BitOperations.TrailingZeroCount(value) + BitOperations.TrailingZeroCount(~value);
|
||
|
}
|
||
|
|
||
|
private static ulong RotateRight(ulong bits, int shift, int size)
|
||
|
{
|
||
|
return (bits >> shift) | ((bits << (size - shift)) & (size == 64 ? ulong.MaxValue : (1UL << size) - 1));
|
||
|
}
|
||
|
}
|
||
|
}
|