ProgrammaTestCPU.txt

ATTENTION, FOR THE EXECUTION OF THIS PROGRAM, THE MEMORY MUST CONTAIN AT STARTUP THE VALUE OF WHICH YOU WANT TO COMPUTE THE FACTORIAL AT LOCATION 1.


Compute Factorial (tested and works good):

    xor $0,$0,$0     00000010  ;set to zero $0
    lw $2,1($0)      8C020001  ;load from address 1 the number of which we will calculate the factorial
    xor $3,$3,$3     00631810  ;set to zero $3
    or $3,$2,$3      00621825  ;copy the initial value of n in $3
    addi $3,$3,-1    2063FFFF  ;decrement the counter of 1 (the removed number is so big because the 2's complement of 1 is -1)
    
L1: beq $3,$0,L2     10600009  ;compare the counter with zero, if is equal, exit
    multu $2,$2,$3   00431019  ;multiply accumulator with counter, e push the result in accumulator, in other words: n=(n)*(n-1)
    addi $3,$3,-1    2063FFFF  ;decrement counter of 1
    j L1             08000005  ;jump to the beginning of the cycle

L2: sw $2,10($0)     AC02000A  ;save the result (the factorial) in the location of memory 10(in decimal), A(in hexadecimal).
    STOP             04000000  ;stop