MarieSimR: The MARIE Computer Simulator Revision

MarieSim is the MARIE computer simulator [1] and MARIE is an accumulator-based computer architecture model used in the textbook [2]. MarieSimR, a revision of MarieSim, is developed to support the use of stack and recursive subroutine. Users can learn and practice more assembly language programming skills with using MarieSimR. In this revision, the stack pointer stored in a reserved memory location and the stack-relative addressing mode are added. The subroutine call and return instructions are revised to use the stack for the subroutine return address. A stack frame can be created for a subroutine to hold the return address, input arguments, output results, local variables and so on. A new instruction for increasing or decreasing the value of the stack pointer is added to facilitate the push and pop operations. In addition, a new instruction for loading an immediate constant into the accumulator is added to replace the clear instruction. Finally, a new assembler directive is also added to support for defining a label to hold the address of another label symbolically. In this paper, the design and implementation of this revision are presented. Two programming applications are also discussed to illustrate how to utilize these new instructions.