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using ARMeilleure.Common;
namespace ARMeilleure.Decoders
{
static class DecoderHelper
{
static DecoderHelper()
{
Imm8ToFP32Table = BuildImm8ToFP32Table();
Imm8ToFP64Table = BuildImm8ToFP64Table();
}
public static readonly uint[] Imm8ToFP32Table;
public static readonly ulong[] Imm8ToFP64Table;
private static uint[] BuildImm8ToFP32Table()
{
uint[] tbl = new uint[256];
for (int idx = 0; idx < tbl.Length; idx++)
{
tbl[idx] = ExpandImm8ToFP32((uint)idx);
}
return tbl;
}
private static ulong[] BuildImm8ToFP64Table()
{
ulong[] tbl = new ulong[256];
for (int idx = 0; idx < tbl.Length; idx++)
{
tbl[idx] = ExpandImm8ToFP64((ulong)idx);
}
return tbl;
}
// abcdefgh -> aBbbbbbc defgh000 00000000 00000000 (B = ~b)
private static uint ExpandImm8ToFP32(uint imm)
{
static uint MoveBit(uint bits, int from, int to)
{
return ((bits >> from) & 1U) << to;
}
return MoveBit(imm, 7, 31) | MoveBit(~imm, 6, 30) |
MoveBit(imm, 6, 29) | MoveBit(imm, 6, 28) |
MoveBit(imm, 6, 27) | MoveBit(imm, 6, 26) |
MoveBit(imm, 6, 25) | MoveBit(imm, 5, 24) |
MoveBit(imm, 4, 23) | MoveBit(imm, 3, 22) |
MoveBit(imm, 2, 21) | MoveBit(imm, 1, 20) |
MoveBit(imm, 0, 19);
}
// abcdefgh -> aBbbbbbb bbcdefgh 00000000 00000000 00000000 00000000 00000000 00000000 (B = ~b)
private static ulong ExpandImm8ToFP64(ulong imm)
{
static ulong MoveBit(ulong bits, int from, int to)
{
return ((bits >> from) & 1UL) << to;
}
return MoveBit(imm, 7, 63) | MoveBit(~imm, 6, 62) |
MoveBit(imm, 6, 61) | MoveBit(imm, 6, 60) |
MoveBit(imm, 6, 59) | MoveBit(imm, 6, 58) |
MoveBit(imm, 6, 57) | MoveBit(imm, 6, 56) |
MoveBit(imm, 6, 55) | MoveBit(imm, 6, 54) |
MoveBit(imm, 5, 53) | MoveBit(imm, 4, 52) |
MoveBit(imm, 3, 51) | MoveBit(imm, 2, 50) |
MoveBit(imm, 1, 49) | MoveBit(imm, 0, 48);
}
public struct BitMask
{
public long WMask;
public long TMask;
public int Pos;
public int Shift;
public bool IsUndefined;
public static BitMask Invalid => new() { IsUndefined = true };
}
public static BitMask DecodeBitMask(int opCode, bool immediate)
{
int immS = (opCode >> 10) & 0x3f;
int immR = (opCode >> 16) & 0x3f;
int n = (opCode >> 22) & 1;
int sf = (opCode >> 31) & 1;
int length = BitUtils.HighestBitSet((~immS & 0x3f) | (n << 6));
if (length < 1 || (sf == 0 && n != 0))
{
return BitMask.Invalid;
}
int size = 1 << length;
int levels = size - 1;
int s = immS & levels;
int r = immR & levels;
if (immediate && s == levels)
{
return BitMask.Invalid;
}
long wMask = BitUtils.FillWithOnes(s + 1);
long tMask = BitUtils.FillWithOnes(((s - r) & levels) + 1);
if (r > 0)
{
wMask = BitUtils.RotateRight(wMask, r, size);
wMask &= BitUtils.FillWithOnes(size);
}
return new BitMask()
{
WMask = BitUtils.Replicate(wMask, size),
TMask = BitUtils.Replicate(tMask, size),
Pos = immS,
Shift = immR,
};
}
public static long DecodeImm24_2(int opCode)
{
return ((long)opCode << 40) >> 38;
}
public static long DecodeImm26_2(int opCode)
{
return ((long)opCode << 38) >> 36;
}
public static long DecodeImmS19_2(int opCode)
{
return (((long)opCode << 40) >> 43) & ~3;
}
public static long DecodeImmS14_2(int opCode)
{
return (((long)opCode << 45) >> 48) & ~3;
}
public static bool VectorArgumentsInvalid(bool q, params int[] args)
{
if (q)
{
for (int i = 0; i < args.Length; i++)
{
if ((args[i] & 1) == 1)
{
return true;
}
}
}
return false;
}
}
}
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