Assemble the below code in Mips Assembler to solve the sudoku below.
input the sudoku in the following grid.
.data
.align 4
#variable of the board
board: .byte 0, 6, 0, 1, 0, 4, 0, 5, 0
.byte 0, 0, 8, 3, 0, 5, 6, 0, 0
.byte 2, 0, 0, 0, 0, 0, 0, 0, 1
.byte 8, 0, 0, 4, 0, 7, 0, 0, 6
.byte 0, 0, 6, 0, 0, 0, 3, 0, 0
.byte 7, 0, 0, 9, 0, 1, 0, 0, 4
.byte 5, 0, 0, 0, 0, 0, 0, 0, 2
.byte 0, 0, 7, 2, 0, 6, 9, 0, 0
.byte 0, 4, 0, 5, 0, 8, 0, 7, 0
new_row: .ascii "\n"
.text
.globl main
main:
#$s0 has the offset
#$s1 has the row
#s2 has the coloum
#$s3 for the number currently testing
move $a0, $zero #first cell with offset 0
jal guess
jal print_grid
j exit
exit:
move $a0, $s0
li $v0, 17
syscall
guess:
#Setup the stack frame and save all the required register's values to be used later
sub $sp, $sp, 20
sw $ra, 16($sp)
sw $s0, 12($sp)
sw $s1, 8($sp)
sw $s2, 4($sp)
sw $s3, 0($sp)
move $s0, $a0
beq $s0, 81, guess_comp #Chekc if it has reached the end of the grid
#iF NOT THE END
li $s3, 9
div $s0, $s3
mflo $s1 #lo holds the quotient
mfhi $s2 #hi has the remainder
lb $t0, board+0($s0)
beq $t0, 0, guess_it # if equal to zero then guess the number to be placed in it
addi $a0, $s0, 1
jal guess
j guess_return
#$a0 has the number
#$a1 has the row
#$a2 has the coloumn
guess_it:
move $a0, $s3
move $a1, $s1
move $a2, $s2
jal check_num
bnez $v0, num_exist
#else
sb $s3, board + 0($s0)
addi $a0, $s0, 1
jal guess
beqz $v0, guess_return
num_exist:
sub $s3, $s3, 1
bnez $s3, guess_it
sb $zero, board + 0($s0)
#else No number is satisfied as already checked from 9 to 1 go back change the previous number and come back
li $v0, 1
j guess_return
guess_comp:
move $v0, $zero
guess_return:
lw $ra, 16($sp)
lw $s0 , 12($sp)
lw $s1, 8($sp)
lw $s2, 4($sp)
lw $s3, 0($sp)
addi $sp, $sp, 20
jr $ra
#set t1 to an element. decrease t0 by 1 and check it with t1
check_num:
li $t0, 9
mul $t1, $a1, $t0 # offset of the first element of the row of the element to guess
check_num_row:
lb $t2, board+0($t1)
beq $t2, $a0, present #Found the element in the row
#else
addi $t1, $t1, 1
sub $t0, $t0, 1
bnez $t0, check_num_row
#else
move $t1, $a2
check_num_col:
lb $t2, board+0($t1)
beq $t2, $a0, present #found the element in the coloumn
#else
addi $t1, $t1, 9
ble $t1, 81, check_num_col
#else
#(success)
move $v0, $zero
j check_success
present:
li $v0, 1
check_success:
jr $ra
#Printing
#s0 holds the offset
#s1 hold row
#s2 hols coloumn
print_grid:
sub $sp, $sp, 16
sw $ra, 12($sp)
sw $s2, 8($sp)
sw $s1, 4($sp)
sw $s0, 0($sp)
la $s0, board #number-> board[0,0]
move $s1, $zero #row ->0
move $s2, $zero #coloum ->0
print_cell:
lb $a0, ($s0) #To print a int
li $v0, 1
syscall
addi $s0, $s0, 1 #add to offset
addi $s2, $s2, 1 #add to coloumn
blt $s2, 9, print_cell #if the coloumn is complted
la $a0, new_row #to print asciiz
li $v0, 4
syscall
move $s2, $zero #reset coloumn to zero
addi $s1, $s1, 1 #add to row
#Check if the row is printed
blt $s1,9, print_cell
lw $s0, 0($sp) # Restore the $s0 register
lw $s1, 4($sp) # Restore the $s1 register
lw $s2, 8($sp) # Restore the $s2 register
lw $ra, 12($sp) # Restore the return address
addi $sp, $sp, 16 # Clean up the stack
jr $ra
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