//a=a-1
void ALU::dec(Register a)
{
if(!a.getValue())
{
m_flags[0] = 1;
}
else
{
m_flags[0] = 0;
}
a.setValue(a.getValue()-1);
}
//a=a*b
void ALU::mul(Register a, Register b)
{
if(a.getValue()>UINT_MAX/b.getValue())
{
m_flags[0] = 1;
}
else
{
m_flags[0] = 0;
}
a.setValue(a.getValue()*b.getValue());
}
//a=b-a
void ALU::rsub(Register a, Register b)
{
if(b.getValue()<a.getValue())
{
m_flags[0] = 1;
}
else
{
m_flags[0] = 0;
}
a.setValue(b.getValue()-a.getValue());
}
//a=a-b
void ALU::sub(Register a, Register b)
{
if(a.getValue()<b.getValue())
{
m_flags[0] = 1;
}
else
{
m_flags[0] = 0;
}
a.setValue(a.getValue()-b.getValue());
}
//a=a+1
void ALU::inc(Register a)
{
if(a.getValue()==UINT_MAX)
{
m_flags[0] = 1;
}
else
{
m_flags[0] = 0;
}
a.setValue(a.getValue()+1);
}
//a=a+b
void ALU::add(Register a,Register b)
{
if(a.getValue()>UINT_MAX-b.getValue())
{
m_flags[0] = 1;
}
else
{
m_flags[0] = 0;
}
a.setValue(a.getValue()+b.getValue());
}
//a=b-a+c-1
void ALU::rsubc(Register a, Register b)
{
unsigned val = b.getValue()-a.getValue()+m_flags[0]-1;
if(b.getValue()<a.getValue()-m_flags[0]+1)
{
m_flags[0] = 1;
}
else
{
m_flags[0] = 0;
}
a.setValue(val);
}
//a=a+b+c
void ALU::addc(Register a,Register b)
{
unsigned val = a.getValue()+b.getValue()+m_flags[0];
if(a.getValue()>UINT_MAX-b.getValue()-m_flags[0])
{
m_flags[0] = 1;
}
else
{
m_flags[0] = 0;
}
a.setValue(val);
}
Value* getErrorInstance(const char* name, const char* message)
{
Register<Value> error = global->get(name);
Register<ListValue> list = new ListValue;
if (message)
{
Register<Value> value = new StringValue(message);
list->push(value);
}
Register<ObjectValue> function = dynamic_cast<ObjectValue*>(error->getValue());
if (!function || !function->getCode())
{
return UndefinedValue::getInstance();
}
return function->call(NullValue::getInstance(), list);
}
//Perform the operation given by the CPU
void ALU::operation(int code, Register a, Register b)
{
//Reset all flags that aren't required
m_flags[1] = 0;
m_flags[2] = 0;
m_flags[3] = 0;
//Check if unary operation
if(!(code==0||code==1||code==4||code==9||code==13||code==16||code==17||code==18||code==19||code==20))
{
//Compare a and b if possible and set flags
if(a.getValue()>b.getValue())
{
m_flags[1] = 1;
}
else if(a.getValue()==b.getValue())
{
m_flags[2] = 1;
}
}
//Perform operation based on code (sets carry flag to 0 if it isn't set in the operation)
if(code==0)
{
zero(a);
m_flags[0] = 0;
}
else if(code==1)
{
one(a);
m_flags[0] = 0;
}
else if(code==2)
{
add(a,b);
}
else if(code==3)
{
addc(a,b);
}
else if(code==4)
{
inc(a);
}
else if(code==5)
{
sub(a,b);
}
else if(code==6)
{
subc(a,b);
}
else if(code==7)
{
rsub(a,b);
}
else if(code==8)
{
rsubc(a,b);
}
else if(code==9)
{
dec(a);
}
else if(code==10)
{
mul(a,b);
}
else if(code==11)
{
random(a);
m_flags[0] = 0;
}
else if(code==16)
{
shl(a);
}
else if(code==17)
{
shlc(a);
}
else if(code==18)
{
shr(a);
}
else if(code==19)
{
shrc(a);
}
else if(code==20)
{
not(a);
m_flags[0] = 0;
}
else if(code==21)
{
and(a,b);
m_flags[0] = 0;
}
else if(code==22)
{
nand(a,b);
m_flags[0] = 0;
}
else if(code==23)
{
or(a,b);
m_flags[0] = 0;
}
else if(code==24)
{
nor(a,b);
m_flags[0] = 0;
}
else if(code==25)
{
xor(a,b);
m_flags[0] = 0;
}
else if(code==26)
{
xnor(a,b);
m_flags[0] = 0;
}
else if(code==27)
{
bclr(a,b);
m_flags[0] = 0;
}
else if(code==31)
{
m_flags[0] = 0;
}
//Check if output is 0 and set flag accordingly
if(a.getValue())
{
m_flags[3]=1;
}
}