static IEnumerable <Instruction> EffectiveMultiplication(RegisterNode dst, RegisterNode mul_reg, ConstantNode <long> mul_val)
{
switch (mul_val.Value)
{
case 2L:
case 4L:
case 8L:
return(new [] {
InstructionFactory.Lea_Mul(dst, mul_reg, mul_val)
});
case 3L:
case 5L:
case 9L:
var tmp_val = new ConstantNode <long> (mul_val.Value - 1L);
return(new [] {
InstructionFactory.Lea_MulAdd(dst, mul_reg, tmp_val, mul_reg)
});
case 1L:
return(new [] {
InstructionFactory.Move(dst, mul_reg)
});
case 0L:
return(new [] {
InstructionFactory.Xor(dst, dst)
});
default:
// dst = mul_reg * mul_val
return(new [] {
InstructionFactory.Move(Target.RAX, mul_val), // RAX = mul_val
InstructionFactory.Mul(mul_reg), // RDX:RAX = mul_reg * mul_val
InstructionFactory.Move(dst, Target.RAX) // dst = RAX
});
}
}
