I'm very new to MIPS and this has me completely baffled. I made a program to convert bases and it works fine the first time through, but when it loops, its displaying the values from the other registers from the previous iterations of the loop. The output is below. I've tried everything that I can think of and I'm out of ideas...
Enter a decimal number: 10
The number in base 2 is 00000000000000000000000000001010
The number in base 4 is 0000000000000022
The number in base 16 is 0000000A
The number in base 8 is 0000000012
Would you like to input another number? 1
Enter a decimal number: 11
The number in base 2 is 0000000000000000000000000000101100000000000000220000000A0000000012
The number in base 4 is 00000000000000230000000A0000000012
The number in base 16 is 0000000B0000000012
The number in base 8 is 0000000013
Would you like to input another number?
.text
.globl __start
__start:
la $a0, prompt # Prompt for a base10 integer
li $v0, 4
syscall
li $v0, 5
syscall
move $a0, $v0
jal bin
jal base4
jal hex
jal base8
la $a0, endl
li $v0, 4
syscall
la $a0, repeat
li $v0, 4
syscall
li $v0, 5
syscall
beqz $v0, eop
la $a0, endl
li $v0, 4
syscall
j __start
eop:
li $v0,10 # End Of Program
syscall
##########################################################
#
# BASE 16
#
##########################################################
hex:
sub $sp, $sp, 24 # Push register onto stack
sw $a0, 0($sp)
sw $s0, 4($sp)
sw $s1, 8($sp)
sw $s2, 12($sp)
sw $s3, 16($sp)
sw $s4, 20($sp)
move $s2, $a0 # Move a0 to s2
la $a0, ans3 # Display string before hex answer
li $v0, 4
syscall
li $s0, 8 # 8 digits for hex word
la $s3, hexresult # Hex string set up here
hexloop:
rol $s2, $s2, 4 # Start with leftmost digit
and $s1, $s2, 0xf # Mask 15 digits in s2 and place results in s1
ble $s1, 9, hexprint # If s1 <= 9, go to print
add $s1, $s1, 7 # Else s1 = s1 + 7 (to get A-F)
hexprint:
add $s1, $s1, 48 # Add 48 (30 hex) to get ascii code
sb $s1,($s3) # Store byte in result. s3 -> result
add $s3, $s3, 1 # s3 = s3 + 1
add $s0, $s0, -1 # s0 = s0 - 1
bnez $s0, hexloop # If s0 != 0, go to hexloop
la $a0, hexresult # display result
li $v0, 4
syscall
jr $ra # Return
##########################################################
#
# BASE 2
#
#########################################################
bin:
sub $sp, $sp, 24 # Push register onto stack
sw $a0, 0($sp)
sw $s0, 4($sp)
sw $s1, 8($sp)
sw $s2, 12($sp)
sw $s3, 16($sp)
sw $s4, 20($sp)
move $s2, $a0 # Move a0 to s2
la $a0, ans1 # Display string before bin answer
li $v0, 4
syscall
li $s0, 32 # 32 digits for base4 word
la $s3, binresult # Bin string set up here
binloop:
rol $s2, $s2, 1 # Start with leftmost digit
and $s1, $s2, 1 # Mask one digit in s2 and place results in s1
binprint:
add $s1, $s1, 48 # Add 48 (30 hex) to get ascii code
sb $s1,($s3) # Store byte in result. s3 -> result
add $s3, $s3, 1 # s3 = s3 + 1
add $s0, $s0, -1 # s0 = s0 - 1
bnez $s0, binloop # If s0 != 0, go to binloop
la $a0, binresult # display result
li $v0, 4
syscall
la $a0, endl
li $v0, 4
syscall
jr $ra # Return
##########################################################
#
# BASE 4
#
#########################################################
base4:
sub $sp, $sp, 24 # Push register onto stack
sw $a0, 0($sp)
sw $s0, 4($sp)
sw $s1, 8($sp)
sw $s2, 12($sp)
sw $s3, 16($sp)
sw $ra, 20($sp)
move $s2, $a0 # Move a0 to s2
la $a0, ans2 # Display string before BASE 4 answer
li $v0, 4
syscall
li $s0, 16 # 16 digits for base4 word
la $s3, base4result # Bin string set up here
base4loop:
rol $s2, $s2, 2 # Start with leftmost digit
and $s1, $s2, 3 # Mask one digit in s2 and place results in s1
fourprint:
add $s1, $s1, 48 # Add 48 (30 hex) to get ascii code
sb $s1,($s3) # Store byte in result. s3 -> result
add $s3, $s3, 1 # s3 = s3 + 1
add $s0, $s0, -1 # s0 = s0 - 1
bnez $s0, base4loop # If s0 != 0, go to binloop
la $a0, base4result # display result
li $v0, 4
syscall
la $a0, endl
li $v0, 4
syscall
jr $ra # Return
##########################################################
#
# BASE 8
#
#########################################################
base8:
sub $sp, $sp, 24 # Push register onto stack
sw $a0, 0($sp)
sw $s0, 4($sp)
sw $s1, 8($sp)
sw $s2, 12($sp)
sw $s3, 16($sp)
sw $ra, 20($sp)
move $s2, $a0 # Move a3 to s2
la $a0, endl
li $v0, 4
syscall
la $a0, ans4 # Display string before bin answer
li $v0, 4
syscall
li $s0, 10 # digits for octal word
la $s3, octresult # Bin string set up here
rol $s2, $s2, 2 # Start with leftmost digit
and $s1, $s2, 0x7 # Mask 7 digits in s2 and place results in s1
base8loop:
rol $s2, $s2, 3 # Start with leftmost digit
and $s1, $s2, 0x7 # Mask 7 digits in s2 and place results in s1
base8print:
add $s1, $s1, 48 # Add 48 (30 hex) to get ascii code
sb $s1,($s3) # Store byte in result. s3 -> result
add $s3, $s3, 1 # s3 = s3 + 1
add $s0, $s0, -1 # s0 = s0 - 1
bnez $s0, base8loop # If s0 != 0, go to binloop
la $a0, octresult # display result
li $v0, 4
syscall
jr $ra # Return
.data
binresult: .space 32
base4result:.space 16
hexresult: .space 8
octresult: .space 10
endl: .asciiz "
"
prompt: .asciiz "Enter a decimal number: "
ans1: .asciiz "The number in base 2 is "
ans2: .asciiz "The number in base 4 is "
ans3: .asciiz "The number in base 16 is "
ans4: .asciiz "The number in base 8 is "
repeat: .asciiz "Would you like to input another number? "
See Question&Answers more detail:
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