3x3 Matrix multiplier...

kponenation · 10-12-2005, 11:32 PM

I wrote 3x3 matrix multiplier in MIPS instructions.
When I run my instructions on SPIM, I get "000," which is not the correct value. Why am I getting this? Can anyone help me fix this problem?

Code:

.data
A:        .word 8, 1, 4, 6, -1, -2, 3, -2, 5
B:        .word 8, 3, 10, 3, 1, 2, 10, 8, 6
C:        .space 36
A_row:        .word 3
A_col:        .word 3
B_row:        .word 3
B_col:        .word 3
.text

main:
	la $s0, A
	la $s1, B
	la $s2, C
	lw $t0, A_row
	lw $t1, A_col
	lw $t2, B_row
	lw $t3, B_col
	li $s3, -1       #i
	li $s4, -1       #j
	li $s5, -1       #k
	j LOOP1


LOOP1:	addi $s3, $s3, 1	# i++
 	bge $s3, $t0, END	
        j LOOP2
	

	


LOOP2:	addi $s4, $s4, 1	# j++
	bge $s4, $t1, LOOP1
        j LOOP3	
	
		

LOOP3: 	addi $s5, $s5, 1	# k++  
	bge $s5, $t2, Show_C			
        mul $s6, $t1, $s3	# s6 = A_col * i
        add $s6, $s6, $s5	# s6 = s6 + k
        mul $s6, $s6, 4		# s6 = s6 * 4
        add $s6, $s6, $s0	# s6 = s6 + A
        lw $t4, 0($s6)		# load s6 to t4

        mul $s7, $t3, $s5	# s7 = B_col * k
        add $s7, $s7, $s4	# s7 = s7 + j
        mul $s7, $s7, 4		# s7 = s7 * 4
        add $s7, $s7, $s1	# s7 = s7 + B
        lw $t5, 0($s7)		# load s7 to t5
 
        mul $s8, $t3, $s3	# s8 = B_col * i
        add $s8, $s8, $s4	# s8 = s8 + j
        mul $s8, $s8, 4		# s8 = s8 * 4
        add $s8, $s8, $s2	# s8 = s8 + C
        mul $t4, $t4, $t5	# t4 = t4 * t5
        add $t6, $t4, $t6	# t6 = t4 + t6
        sw  $t6, 0($s8)		# store s8 to t6     
	 
	j LOOP3
		

Show_C: li $v0, 1
	lw $s0, 0($s8)
 	syscall		
	j LOOP2
        
END:	li $v0, 10
	lw $s0, 0($s8)
	syscall

Thanks in advance...

j

naf · 10-27-2005, 09:16 AM

My understanding is that a 3x3 matrix multiplied to anohter 3x3 matrix results in a 3x3 matrix. So the result should be nine digits. I cannot find where the inner loops are reset to -1 at the beginning of each loop. Instead of: j LOOP2, how about li $s4, -1 and li $s5, -1 for j LOOP3.