Var expression

All code which accesses memory is compiled with the VarExpression class.

The primary function in this class is the compileExpressionToRegister method:

compileExpressionToRegister(identifier, expression, reg, forWriting, selfPointerStackOffset)

This function compiles a given expression to code which calculates the address of the expression.

The parameters of this function are:

• identifier: The identifier information which is the search result of searching for the first expression lexeme in the active scopp. It can be a variable, procedure or field.
• expression: The expression to compile.
• reg: The register in which the resulting offset is stored.
• forWriting: Is the expression for reading or writing to memory.
• selfPointerStackOffset: If given then the found object pointer will be stored at this offset on the stack.