Project #7 Solution

Description

Assignment Overview

This assignment develops familiarity with the instruction set architecture of the ARM microprocessor, as well as the format of its machine language instructions.

Assignment Deliverables

The deliverables for this assignment are the following files:

proj07.makefile – the makefile which produces “proj07” proj07.support.c – the source code for your support module

Be sure to use the specified file names and to submit them for grading via the CSE handin system before the project deadline.

Assignment Specifications

The program will simulate the actions of the CPU during the fetch-execute cycle for the ARM microprocessor.

1. The instructor-supplied driver module contains the definition of function “main” and some auxiliary functions. For each machine language instruction to be processed, it will simulate the steps of the fetch phase of the cycle and will then call function “execute” to simulate the steps of the execute phase.

2. You will develop a support module which can be used to process a subset of the ARM machine language instructions. The interface to the support module is the following C function:

void execute();

Function “execute” will decode and process the instruction in the IR, then update the register file and the CPSR (when appropriate). It will recognize only the 16 data processing instructions as legal instructions.

3. The driver module and your support module will communicate using the following global data objects: unsigned int IR, CPSR;

The driver module will place values into those two variables before calling function “execute”; function “execute” will use those values for its processing and will update variable “CPSR” before returning.

4. In the CPSR, bits 31:28 are the integer condition codes and bit 0 is the illegal instruction flag (1 means illegal).

Assignment Notes

1. Your driver module and your support module must be in separate source code files.

2. Your source code must be translated by “gcc”, which is a C compiler and accepts C source statements.

3. You must supply a “makefile” (named “proj07.makefile”), and that makefile must produce an executable program named “proj07”.

3. Function “execute” will recognize the ARM data processing instructions, which have the following format:

All other bits will be 0 in a legal instruction.

The sixteen operation codes are given in the following table:

Opcode	Mnemonic		Opcode	Mnemonic
0000	and		1000	tst
0001	eor		1001	teq
0010	sub		1010	cmp
0011	rsb		1011	cmn
0100	add		1100	orr
0101	adc		1101	mov
0110	sbc		1110	bic
0111	rsc		1111	mvn

5. Note that the functions in your support module cannot perform any input or output operations. All communication between the driver module and the support module will be done via the global variables.

5. The file named “/user/cse320/Projects/project07.hardware.h” contains the following declarations (see the file for additional comments):

typedef unsigned		int signal4;
typedef unsigned		int signal32;
extern unsigned int IR, CPSR;
void read_reg_file
(
signal4,	/* RS1 selection signal */
signal4,	/* RS2 selection signal */
signal32*,	/* RS1 output port		*/
signal32*	/* RS2 output port		*/
);
void write_reg_file
(
signal4,	/* RD selection signal		*/
signal32	/* RD input port		*/
);