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ALU.cpp
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ALU.cpp
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#ifndef VM_Component_ALU
#define VM_Component_ALU
#include <stdint.h>
#include "HwError.hpp"
#include "Component.hpp"
namespace Component
{
class ALU : public Component_t
{
public:
typedef enum
{
ALUOp_AddOrSub = 0b000,
ALUOp_ShiftLeft = 0b001,
ALUOp_SetLessThan = 0b010,
ALUOp_SetLessThanUnsigned = 0b011,
ALUOp_Xor = 0b100,
ALUOp_ShiftRightOrArith = 0b101,
ALUOp_Or = 0b110,
ALUOp_And = 0b111
} ALUOp;
Component_ID GetID() override
{
return Component_ID_ALU;
}
uint64_t DoALUOp( uint8_t Op, uint64_t r1, uint64_t r2, bool invertOp )
{
return DoALUOp( (ALUOp) Op, r1, r2, invertOp );
}
uint64_t DoALUOp( ALUOp Op, uint64_t r1, uint64_t r2, bool invertOp )
{
static void* Pointers[] = { &&AddOrSub, &&ShiftLeft, &&SetLessThan, &&SetLessThanUnsigned, &&OP_XOR, &&ShiftRightOrArithmetic, &&OP_OR, &&OP_AND };
SetLastHwError( HwError_NoError );
uint8_t OpOffset = (uint8_t) Op;
if( OpOffset <= 0b111 )
goto *Pointers[OpOffset];
else
goto BADINSTRUCTION;
// 0b000
AddOrSub:
{
if( invertOp )
r2 = -r2;
return r1 + r2;
}
// 0b001
ShiftLeft:
{
return (r2 < 64) ? (r1 << r2) : 0;
}
// 0b010
SetLessThan:
{
int64_t sr1 = (int64_t) r1;
int64_t sr2 = (int64_t) r2;
return (sr1 < sr2) ? 1 : 0;
}
// 0b011
SetLessThanUnsigned:
{
return (r1 < r2) ? 1 : 0;
}
// 0b100
OP_XOR:
{
return r1 ^ r2;
}
// 0b101
ShiftRightOrArithmetic:
{
bool bit = ( r1 >> 63 & 1 ) != 0;
uint64_t OnlyOnes = -1;
uint64_t rawShift = r1 >> r2;
if( invertOp && bit )
{
return rawShift | (OnlyOnes << (64 - r2) );
}
else
{
return rawShift & (OnlyOnes >> r2);
}
}
// 0b110
OP_OR:
{
return r1 | r2;
}
// 0b111
OP_AND:
{
return r1 & r2;
}
BADINSTRUCTION:
{
SetLastHwError( HwError_InvalidAluOp );
return -1;
}
}
};
};
#endif