MIPS-single-cycle

MIPS single cycle Verilog implementation based on Computer Organization and Design The Hardware software Interface by David A. Patterson and John L. Hennessy.

Overview

The implementation supports 1 cycle per instruction add, sub, lw, sw, beq and slt. Based on the implementation scheme from chapter 4, The Processor: Datapath and Control of Computer Organization and Design by David A. Patterson and John L. Hennessy, 5th edition. The memory is structured in 32-bit words.

The instruction memory file, meminstr.dat contains the codes for the following program:

add $t0, $zero, $zero
add $t6, $zero, $zero

lw $t1, 64($t0)
lw $t2, 68($t0)
lw $t3, 72($t0)
sw $zero, 76($t0) #the sum will be at this location [76]
loop:
lw $t4, 0($t0)
lw $t5, 76($t6)
add $t5, $t5, $t4
sw $t5, 76($t6)
sub $t1, $t1, $t2
add $t0, $t0, $t3
beq $t1, $zero, done
beq $t1, $t1, loop #actually jump (because $t1 = $t1)
done:
nop

The program computes the sum of the first 16 values from the data memory. The result will be 5 and will be located in the data memory.

Tools

Modelsim was used for simulation. There is a free student edition available. QtSpim was used to view the codes for each instruction.