ascii - MIPS Check if equal to a certain character -

i trying write sprinf in mips. first, trying count how many characters there are.

sprintf:     addi $sp, $sp, -12     sw $ra, 8($sp)     sw $s1, 4($sp)     sw $s2, 0($sp)             li      $s0, 0          # len = 1         la      $s1, ($a1)        # s = str test:         lb      $s2, 0($s1)     # c = *s         beqz    $s2, done       # if c == '\0', branch "done"         beq $s2, '5', done         addi    $s0, $s0, 1     # len = len + 1         addi    $s1, $s1, 1     # s = s + 1         j       test  percent:     done:         li      $v0, 1          # syscall code: print_int         move    $a0, $s0         syscall         li      $v0, 11         # syscall code: print_char         li      $a0, 10         # pass newline character         syscall          jr      $ra 

but there need check if in format when there %d, or %c ,etc.

how check character that? saw mips ascii http://galia.fc.uaslp.mx/~luis/arquitectura_files/table.pdf

but beq like?

there's no need consult ascii table. assembler worth using supports character immediates. can do:

lbu $s2,($s1) li $t0,'%' bne $s2,$t0,not_percent_sign 

or if assembler supports branch pseduo-instructions immediates:

lbu $s2,($s1) bne $s2,'%',not_percent_sign