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using Ryujinx.Graphics.Shader.IntermediateRepresentation;
using Ryujinx.Graphics.Shader.Translation;
using static Ryujinx.Graphics.Shader.IntermediateRepresentation.OperandHelper;
namespace Ryujinx.Graphics.Shader.Instructions
{
static class Lop3Expression
{
public static Operand GetFromTruthTable(EmitterContext context, Operand srcA, Operand srcB, Operand srcC, int imm)
{
Operand expr = null;
// Handle some simple cases, or cases where
// the KMap would yield poor results (like XORs).
if (imm == 0x96 || imm == 0x69)
{
// XOR (0x96) and XNOR (0x69).
if (imm == 0x69)
{
srcA = context.BitwiseNot(srcA);
}
expr = context.BitwiseExclusiveOr(srcA, srcB);
expr = context.BitwiseExclusiveOr(expr, srcC);
return expr;
}
else if (imm == 0)
{
// Always false.
return Const(IrConsts.False);
}
else if (imm == 0xff)
{
// Always true.
return Const(IrConsts.True);
}
int map;
// Encode into gray code.
map = ((imm >> 0) & 1) << 0;
map |= ((imm >> 1) & 1) << 4;
map |= ((imm >> 2) & 1) << 1;
map |= ((imm >> 3) & 1) << 5;
map |= ((imm >> 4) & 1) << 3;
map |= ((imm >> 5) & 1) << 7;
map |= ((imm >> 6) & 1) << 2;
map |= ((imm >> 7) & 1) << 6;
// Solve KMap, get sum of products.
int visited = 0;
for (int index = 0; index < 8 && visited != 0xff; index++)
{
if ((map & (1 << index)) == 0)
{
continue;
}
int mask = 0;
for (int mSize = 4; mSize != 0; mSize >>= 1)
{
mask = RotateLeft4((1 << mSize) - 1, index & 3) << (index & 4);
if ((map & mask) == mask)
{
break;
}
}
// The mask should wrap, if we are on the high row, shift to low etc.
int mask2 = (index & 4) != 0 ? mask >> 4 : mask << 4;
if ((map & mask2) == mask2)
{
mask |= mask2;
}
if ((mask & visited) == mask)
{
continue;
}
bool notA = (mask & 0x33) != 0;
bool notB = (mask & 0x99) != 0;
bool notC = (mask & 0x0f) != 0;
bool aChanges = (mask & 0xcc) != 0 && notA;
bool bChanges = (mask & 0x66) != 0 && notB;
bool cChanges = (mask & 0xf0) != 0 && notC;
Operand localExpr = null;
void And(Operand source)
{
if (localExpr != null)
{
localExpr = context.BitwiseAnd(localExpr, source);
}
else
{
localExpr = source;
}
}
if (!aChanges)
{
And(context.BitwiseNot(srcA, notA));
}
if (!bChanges)
{
And(context.BitwiseNot(srcB, notB));
}
if (!cChanges)
{
And(context.BitwiseNot(srcC, notC));
}
if (expr != null)
{
expr = context.BitwiseOr(expr, localExpr);
}
else
{
expr = localExpr;
}
visited |= mask;
}
return expr;
}
private static int RotateLeft4(int value, int shift)
{
return ((value << shift) | (value >> (4 - shift))) & 0xf;
}
}
}
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