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// addressing.h
#include "addressing.h"
address fAddressGetAddress(Addressing mode, address x)
{
switch(mode)
{
case eImplied:
case eRelative:
case eImmediate:
case eAccumulator:
return 0x0000;
case eAbsolute:
return x;
case eIndirectAbsolute:
return (((address)GetMemory(x+1)) << 8) + (address)GetMemory(x);
case eAbsoluteIndexedX:
return x + X;
case eAbsoluteIndexedY:
return x + Y;
case eZeroPage:
return x & 0x00FF;
case eZeroPageIndexedX:
return ((x + X) & 0x00FF);
case eZeroPageIndexedY:
return ((x + Y) & 0x00FF);
case eIndexedIndirect:
return (((address)(GetMemory(x+X+1))) << 8) + (address)(GetMemory(x+X));
case eIndirectIndexed:
return ((address)(GetMemory(x+1)) << 8) + ((address)(GetMemory(x))) + ((address)Y);
}
}
int fAddressGetLength(Addressing mode)
{
switch(mode)
{
case eAbsolute: case eAbsoluteIndexedX: case eAbsoluteIndexedY: case eIndirectAbsolute:
return 3;
case eAccumulator: case eImplied:
return 1;
default:
return 2;
}
}
byte fAddressGetValue(Addressing mode, address x, address addr)
{
switch(mode)
{
case eImplied:
return 0;
case eRelative:
case eImmediate:
return x;
case eAccumulator:
return acc;
default:
return GetMemory(addr);
}
}
struct State fAddress(Addressing mode, address x)
{
struct State ret;
ret.address = fAddressGetAddress (mode, x);
ret.value = fAddressGetValue (mode, x, ret.address);
ret.length = fAddressGetLength (mode);
return ret;
}
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