Assembly floating point

[serendipity.]

Hey there!

I had to write a programme for MIPS/SPIM, which reads floating point numbers and returns them bit by bit at the shell. So this is, what I managed to write:

.data
var1:		.float 		0.00
var2:		.float 		2.0
var3:		.float 		-0.123
txt2:		.asciiz		"\n"

.text

main:
addi	$sp, $sp, -20		# decrement stack pointer
l.s	$f0, var3		# load var3 in $f0
s.s	$f0, 20($sp)		# push $f0 on stack
addi	$sp, $sp, -20		# decrement stack pointer
l.s	$f1, var2		# load var2 in $f1
s.s	$f1, 20($sp)		# push $f1 on stack
addi	$sp, $sp, -20		# decrement stack pointer
l.s	$f2, var1		# load var1 in $f2
s.s	$f2, 20($sp)		# push $f2 on stack


li	$t3, 3			# $t3 = 3: number of floats

for1:
sub	$t3, $t3, 1		# decrement $t3
l.s	$f0, 4($sp)		# load first byte from stack in $f0
addi	$sp, $sp, 4		# increment stack pointer
li	$t7, 1			# preparation: $t7 = 1
li 	$t6, 0			# preparation: $t6 = 0
li	$t0, 1			# preparation: $t0 = 1
mfc1	$t2, $f0		# move from coprocessor: $t2 = $f0

for2:
and	$t1, $t2, $t0		# logical and: $t1 = $t2 AND $t0
sll	$t0, $t0, 1		# shift left logical: $t0 = $t0 * 2^1
bne	$zero, $t1, case_1	# if $t1 /= 0 branch to case_1
addi	$sp, -4			# decrement stack pointer
sw	$zero, 4($sp)		# push $zero (=0) on stack
b	go_on			# branch to go_on

case_1:
addi	$sp, -4			# decrement stack pointer
sw	$t7, 4($sp)		# push $t7 (=1) on stack

go_on:
addi	$t6, $t6, 1		# increment $t6
bne	$zero, $t0, for2	# if $t0 /= 0 branch to for2

li	$v0, 1			# print_int

for3:
lw	$a0, 4($sp)		# load in $a0 value from stack on address 4($sp)
addi	$sp, 4			# increment stack pointer
syscall				# print
sub	$t6, $t6, 1		# decrement $t6
bne	$zero, $t6, for3	# if $t6 /= 0 branch to for3
li	$v0, 4			# print_string
la	$a0, txt2		# load in $a0 address txt2 
syscall				# print "\n"

bne	$zero, $t3, for1	# if $t3 /= 0 branch to for1

li	$v0, 10			# exit
syscall

It works, but somehow I've got the impression, that it always returns the same numbers (even if I've changed the floating point numbers in the .data-section).
I've got no idea, where the problem could be... Maybe someones got a hint for me?