// REGISTERS
// Generates code to fetch the value of a named constant or variable
// and push it on to the stack.
// currentLevel is the routine level where the vname occurs.
// frameSize is the anticipated size of the local stack frame when
// the constant or variable is fetched at run-time.
// valSize is the size of the constant or variable's value.
void EncodeAssign(Identifier identifier, Frame frame, int valSize)
{
AddressableEntity baseObject = identifier.Declaration.Entity as AddressableEntity;
// If indexed = true, code will have been generated to load an index
// value.
if (valSize > 255)
{
errorReporter.ReportMessage("can't store values larger than 255 words");
valSize = 255; // to allow code generation to continue
}
baseObject.EncodeAssign(emitter, frame, valSize, identifier);
}
/// <summary>
/// Appends an instruction, with the given fields, to the object code.
/// </summary>
/// <param name="op">the opcode</param>
/// <param name="length">the length field</param>
/// <param name="register">the register field</param>
/// <param name="operand">the operand field</param>
/// <returns>the code address of the new instruction</returns>
public int Emit(OpCode op, int length, Register register, int operand)
{
if (length > 255)
{
errorReporter.ReportMessage("length of operand can't exceed 255 words");
length = 255; // to allow code generation to continue
}
Instruction nextInstr = new Instruction(op, register, length, operand);
int currentInstrAddr = NextInstrAddr;
if (NextInstrAddr == Machine.PrimitiveBase)
{
errorReporter.ReportMessage("too many instructions for code segment");
}
else
{
Machine.Code[NextInstrAddr++] = nextInstr;
}
return(currentInstrAddr);
}