You seem to be having branches in jump delay slots. Also there are some loads in delay slots which I think might not be intentional. You might want to check these. e.g. load in a branch/jump delay slot ( intentional ? ) j r1 cr: li $13,0 # clear line number e.g. branch in an jump delay slot (?) j r2 r3: bne $19,$10,exit # branch if line total != magic number Thanks Ranjan -----Original Message----- From: Michael [mailto:trott@bigpond.net.au] Sent: Tuesday, August 05, 2003 9:10 PM To: linux-mips@linux-mips.org Subject: debuging problems i have written a mips program to verify if a given input is a magic square, a magic square is a n*n matrix whose values are from 1..n^2, and each row/column diagonal gives the same sum, this sum is know as the magic number. All my program does is go through and sum each of the rows then each of the columns, at every stage the sum of the row or column in question is compared to the magic number, if not equal then not valid magic square. the formula is given in my doco. im having problems working out what the actual problem is. I've completely coded it and spent alot of time steping through it but i cant see any problems. regardless of the input, the result is always negative. just wondering has anyone got any suggestions, any help would be greatly appreicated :) ive pasted my program at the bottom of this, thanks everyone michael _______________________________________________________________ # Program Name: Magic Square Verifier # # Author: Michael # # The purpose of this program is to determine whether or not # a given input is a valid magic square. # # The start address for the matrix is to be given in $8, with # the size of the matrix supplied in $9. Major row # representation must be used to store the matrix values. # # At completeion of the program, $11 will store the # result of the program. if $11 == 1, then input was a # valid magic square, if $11 == 0, the input was not a valid # magic square. # # for more details, plese consult the attached program # description file .text main: li $11,0 # is magic square = 0 li $12,2 # temporary li $13,0 # Line number li $14,0 # temporary li $16,0 # Line position li $17,0 # start address + offset li $18,4 # constant 4 li $19,0 # Line total # Calculation of magic number for specified n mul $10,$9,$9 # n^2 addi $10,$10,1 # (n^2)+1 mul $10,$10,$9 # ((n^2)+1)n divu $10,$10,$12 # (((n^2)+1)n)/2 == magic_number addi $15,$9,1 # n+1 r1: beq $13,$9,cr # branch if line# == n r2: beq $16,$9,r3 # branch when line_pos == n mul $12,$13,$9 # line# . n add $12,$12,$16 # (line # . n)+ line_pos mul $12,$12,$18 # ((line # . n)+ line_pos)4 add $17,$8,$12 # start address + offset lw $23, 0($17) # load word, viz[i], into $17 add $19,$19,$23 # line_total = line_total + viz[i] addi $16,$16,1 # line_position ++ j r2 r3: bne $19,$10,exit # branch if line total != magic number addi $13,$13,1 # line# ++ li $16,0 # set line_pos j r1 cr: li $13,0 # clear line number li $16,0 # clear line position li $19,0 # clear line total c1: beq $13,$9,sum # branch if line# == n c2: beq $16,$9,c3 # branch if line# == n mul $12,$9,$18 # n . 4 mul $12,$12,$16 # (n . 4) . line_position mul $14,$13,$18 # line# . 4 add $12,$12,$14 # ((n . 4) . line_position)+( line# . 4) add $17,$12,$8 # start address + offset lw $23,0($17) # load word, viz[i], into $17 add $19,$19,$23 # start address + offset addi $16,$16,1 # line_total = line_total + viz[i] j c2 c3: bne $19,$10,exit # branch if line_total != magic_number addi $13,$13,1 # line# ++ li $16,0 # clear line _pos j c1 sum: li $12,0 li $14,0 add $17,$8,$0 s1: beq $12,$9,s2 # branch if counter == n lw $23,0($17) # load word, viz[i], into $17 add $14,$14,$23 # seq_total = seq_total + viz[i] addi $17,$17,4 # viz[i] = viz[i + 1] addi $12,$12,1 # counter ++ j s1 s2: li $16,0 # total li $19,1 # i of n s3: beq $19,$15,s4 # branch if (i of n ) == (n + 1) add $16,$16,$19 # total = total + (i of n ) addi $19,$19,1 # (i of n ) ++ s4: bne $16,$14,exit dc: li $12,0 li $13,0 li $16,0 li $19,0 mul $14,$15,$18 # (n + 1) 4 add $17,$8,$0 # copy start addr to $17 d1: beq $13,$9,d2 # branch if line# == n lw $23,0($17) # load word, viz[i], into $17 add $19,$19,$23 # diag_total = diag_total + viz[i] add $17,$17,$14 # viz[i] = viz[i+1] addi $13,$13,1 # line# ++ j d1 d2: bne $19,$10,exit # branch if diagonal_total != magic_number j complete # else complete, therefore input is magic square complete: li $11,1 exit:
