static List<CStatement> Rlwinm_C(uint pc, uint instruction)
{
/**
* Very complex instruction
* RA = RotateLeft(RS, SH) & ((0xFFFFFFFF >> MB) ^ (0xFFFFFFFF >> ME));
*
* Can be simplified:
* if (MB == 0 && ME + SH == 31)
* ShiftLeft (BigEndian) = ShiftRight (LittleEndian)
* if (ME == 31 && SH + MB == 32)
* ShiftRight (BigEndian) = ShiftLeft
* if (SH == 0 && ME == 31)
* ClearLeft = ClearRight
* if (SH == 0 && MB == 0)
* ClearRight = ClearLeft
* if (MB == 0 && ME == 31)
* Rotate
*
* extlwi rA,rS,n,b equivalent to rlwinm rA,rS,b,0,n – 1
* extrwi rA,rS,n,b equivalent to rlwinm rA,rS,b + n,32 – n,31
* clrlslwi rA,rS,b,n equivalent to rlwinm rA,rS,n,b – n,31 – n
*/
List<CStatement> stats = new List<CStatement>();
Instruction i = new Instruction(instruction);
if (i.MB() == 0)
{
if (i.ME() == 31)
{
/*
* Rotate left - Rotate right...
* ((x >> n) | (x << (32 - n)))
*/
uint n = i.SH();
CStatement lsh = new CStatement(CStatement.Kinds.LeftShift, RegName(i.RS()), 32 - n);
CStatement rsh = new CStatement(CStatement.Kinds.RightShift, RegName(i.RS()), n);
CStatement or = new CStatement(CStatement.Kinds.Or, rsh, lsh);
CStatement ass = new CStatement(CStatement.Kinds.Assignment, RegName(i.RA()), or);
stats.Add(ass);
}
else if (i.ME() + i.SH() == 31)
{
/* ShiftLeft = ShiftRight */
uint n = i.SH();
CStatement rsh = new CStatement(CStatement.Kinds.RightShift, RegName(i.RS()), n);
CStatement ass = new CStatement(CStatement.Kinds.Assignment, RegName(i.RA()), rsh);
stats.Add(ass);
}
else if (i.SH() == 0)
{
/* ClearRight = ClearLeft */
uint n = 31 - i.ME();
uint mask = 0xFFFFFFFF << (int)n;
CStatement and = new CStatement(CStatement.Kinds.And, RegName(i.RS()), mask);
CStatement ass = new CStatement(CStatement.Kinds.Assignment, RegName(i.RA()), and);
stats.Add(ass);
}
}
else if (i.ME() == 31 && i.SH() + i.MB() == 32)
{
/* ShiftRight = ShiftLeft */
uint n = i.MB();
CStatement lsh = new CStatement(CStatement.Kinds.LeftShift, RegName(i.RS()), n);
CStatement ass = new CStatement(CStatement.Kinds.Assignment, RegName(i.RA()), lsh);
stats.Add(ass);
}
else if (i.SH() == 0)
{
if (i.ME() == 31)
{
/* ClearLeft = ClearRight */
uint n = i.MB();
uint mask = 0xFFFFFFFF ^ (0xFFFFFFFF << (int)n);
CStatement and = new CStatement(CStatement.Kinds.And, RegName(i.RS()), mask);
CStatement ass = new CStatement(CStatement.Kinds.Assignment, RegName(i.RA()), and);
stats.Add(ass);
}
else
{
/* And without rotate */
uint m1 = 0xFFFFFFFF >> (int)(i.ME() + 1);
uint m2 = 0xFFFFFFFF >> (int)i.MB();
uint mask = m1 ^ m2;
CStatement and = new CStatement(CStatement.Kinds.And, RegName(i.RS()), mask);
CStatement ass = new CStatement(CStatement.Kinds.Assignment, RegName(i.RA()), and);
stats.Add(ass);
}
}
else
{
/* Rotate, then and */
uint n = i.SH();
uint m1 = 0xFFFFFFFF << (int)i.MB();
uint m2 = 0xFFFFFFFF << (int)i.ME();
uint mask = m1 ^ m2;
CStatement lsh = new CStatement(CStatement.Kinds.LeftShift, RegName(i.RS()), 32 - n);
CStatement rsh = new CStatement(CStatement.Kinds.RightShift, RegName(i.RS()), n);
CStatement or = new CStatement(CStatement.Kinds.Or, rsh, lsh);
CStatement and = new CStatement(CStatement.Kinds.And, or, mask);
CStatement ass = new CStatement(CStatement.Kinds.Assignment, RegName(i.RA()), and);
stats.Add(ass);
}
if (i.RC())
stats.Add(new CStatement(CStatement.Kinds.Assignment, "cr0", RegName(i.RA())));
return stats;
}
static List<CStatement> Rlwimi_C(uint pc, uint instruction)
{
List<CStatement> stats = new List<CStatement>();
Instruction i = new Instruction(instruction);
uint m1 = 0xFFFFFFFF << (int)i.ME();
uint m2 = 0xFFFFFFFF << (int)i.MB();
uint mask = m1 ^ m2;
CStatement lsh = new CStatement(CStatement.Kinds.LeftShift, RegName(i.RS()), 32 - i.SH());
CStatement rsh = new CStatement(CStatement.Kinds.RightShift, RegName(i.RS()), i.SH());
CStatement orRot = new CStatement(CStatement.Kinds.Or, rsh, lsh);
CStatement notMask = new CStatement(CStatement.Kinds.BinaryNot, mask);
CStatement and1 = new CStatement(CStatement.Kinds.And, orRot, mask);
CStatement and2 = new CStatement(CStatement.Kinds.And, RegName(i.RA()), notMask);
CStatement or = new CStatement(CStatement.Kinds.Or, and1, and2);
CStatement ass = new CStatement(CStatement.Kinds.Assignment, RegName(i.RA()), or);
stats.Add(ass);
/* RA = (ROTL(RS, i.SH) & mask) | (RA & ~mask); */
if (i.RC())
stats.Add(new CStatement(CStatement.Kinds.Assignment, "cr0", RegName(i.RA())));
return stats;
}