# floating-point multiplication
.data
newline:    .asciiz       "\n"
.text 
main:
        addiu       $v0, $zero, 6		# read a single 
        syscall
        mfc1        $a0, $f0
        mov.s      $f1, $f0
        addiu       $v0, $zero, 6
        syscall
        mfc1        $a1, $f0
        mov.s      $f2, $f0
        jal            fmult
        mtc1        $v0, $f12
        addiu       $v0, $zero, 2		#display a single
        syscall
        addiu       $v0, $zero, 4
        la             $a0, newline
        syscall
        mul.s       $f12, $f1, $f2
        addiu       $v0, $zero, 2
        syscall
        addiu       $v0, $zero, 10
        syscall

# Preconditions:	
#   1st parameter (a0) single precision floating point multiplicand
#   2nd parameter (a1) single precision floating point multiplier
# Postconditions:
#   result (v0) single precision floating point product

fmult:					# v0 = 0, the default result
					# return if multiplicand is zero
					# return if multiplier is zero
	
	# place mask for leftmost bit in t5
					# t5 = 0x80000000
	
	# place sign of multiplicand in t0
					# mask off exponent and significand

	# place sign of multiplier in t1
					# mask off exponent and significand

	# place sign of product in t2
					# t2 = xor of signs

	# place exponent of multiplicand in t0
					# shift to remove sign bit
					# shift to remove significand bits
					# subract exponent bias

	# place exponent of multiplier in t1
					# shift to remove sign bit
					# shift to remove significand bits
					# subract exponent bias

	# place exponent of product in t3
	# ignore the possibility of overflow or underflow
					# t3 = sum of exponents
					# add exponent bias
	
	# place significand of multiplicand in t0
					# shift to remove exponent
					# restore implicit 1 to left of significand

	# place significand of multiplier in t1
					# shift to remove exponent
					# restore implicit 1 to left of significand

	# place significand of product in t4
	# ignore rounding and overflow
					# multiply significands (unsigned)
					# t4 = high word of product
					# branch if already normalized
					# shift significand to normalize
					# adjust exponent
norm:					# shift to remove implicit 1

	# assemble product in v0
					# shift exponent into proper position
					# shift significand into proper position
					# place sign in v0
					# place exponent in v0
					# place significand in v0

return:					# return