########################################################
# Homework Assignment 2
# Name =
# Floating point is described in section 9.6 in our text.
########################################################

	.data
				# Store the parsed opcode/registers in parsed
float:  .float  43000000
parsed: .word   0,0,0    #sign, exponent, significand

HexTbl: 			# Nibble Hexadecimal Tranlation Table
	.asciiz	"0"	# 0
	.asciiz	"1"
	.asciiz	"2"
	.asciiz	"3"
	.asciiz	"4"
	.asciiz	"5"
	.asciiz	"6"
	.asciiz	"7"
	.asciiz	"8"
	.asciiz	"9"
	.asciiz	"a"
	.asciiz	"b"
	.asciiz	"c"	# 12
	.asciiz	"d"
	.asciiz	"e"
	.asciiz	"f"

	.text
	.globl main
########################### Program ######################
# This program interprets floating point data
#
# Pseudocode:
#   print("Hexadecimal:")
#   parse(float, parsed)
#   print_sign(sign)
#   print_mantissa(significand) // in hexadecimal
#   print_exponent(exponent)   // in hexadecimal
#   print("Decimal:" + float)  // print in decimal
#
# Stack Usage:
#
# Register Conventions:
#
########################################################
# The call to syscall has the following parameters:
#   $a0: thing to be printed
#   $v0: Mode
#       1=integer
#       4=null-terminated string
########################################################
main:
#   						print("Hexadecimal:")
#   						parse(float, parsed)
	lw 	$t1,float
	sw	$t1,-4($sp)
	la	$t1,parsed
	sw	$t1,-8($sp)
	jal	Parse
#   						print_sign(sign)
	lw	$a1,parsed
	jal	PrSign
#   						print_mantissa(significand) // in hexadecimal
#   						print_exponent(exponent)   // in hexadecimal
#   						print("Decimal:" + float)  // print in decimal
	li	v0,10			# exit
	syscall

########################################################
# Parse: This procedure parses a floating point single into an array
#   // Single-precision
#	sign = data[31]
#   exponent = data[23-30]
#   significand = data[0-22]
#
# Calling Sequence:
#   sw  $rX,-4($sp)	# Floating point data
#   sw  $rY,-8($sp)	# Address of array to parse into
#   jal Parse
#
# Returns:  In the output array, the following is stored:
#   Word 0: Sign
#   Word 1: Exponent
#   Word 2: Significand or Mantissa
#
# Stack Usage:
#
# Register Convention:
########################################################
Parse:
	addi	$sp,$sp,-12
	sw	$ra,0($sp)
	lw	$t1,4($sp)
	lw	$t2,8($sp)
#						sign = data[31]
#   						exponent = data[23-30]
#   						significand = data[0-22]
	lw	$ra,0($sp)
	addi	$sp,$sp,+12
	jr	$ra

########################################################
# PrSign: Prints a Sign
#
# Pseudocode:
#   if sign == 0 print +
#   else if sign == 1 print -
#
# Calling Sequence:
#   lw  $a1, <sign>
#   jal PrSign
#
# Returns: Nothing
#
# Stack Usage:
#
# Register Convention:
########################################################
PrSign:
	jr	$ra

########################################################
# PrintMant: Prints the significand (or mantissa) passed as a parameter
#
# Pseudocode:
#   Print "1."
#   Shift significand 1 bit to the left to get 24 bits to print
#   Print significand nibbles in hexadecimal (call PrintHex)
#
# Calling Sequence:
#   sw   $rX,-4($sp)	# Significand
#   jal  PrMant
#
# Returns: Nothing
#
# Stack Usage:
#
# Register Convention:
########################################################
PrMant:
	jr	$ra
########################################################
# PrintHex: Prints the number passed as a parameter in hex
#
# Pseudocode:
#   For each nibble do:
#      nibble = (word &gt;&gt; shiftnum)
#      nibble = nibble.maskBottom4Bits()
#      address = (nibble * 2) + HexTbl
#      Print(*address)  // nibble in ASCII from table
#   Until all nibbles printed
#
# Calling Sequence:
#   lw   $a1, <hex number>
#   lw   $a2, <number of bits to print>
#   jal  PrintHex
#
# Returns: Nothing
#
# Stack Usage:
#
# Register Convention:
########################################################
PrintHex:
	jr	$ra
########################################################
# PrintExp: Prints the exponent passed as a parameter
#
# Pseudocode:
#   exponent = exponent - 127
#   print ' x 2**'
#   print exponent (in hex)
#   print linefeed
#
# Calling Sequence:
#   lw   $a1, <exponent>
#   jal  PrintExp
#
# Returns: Nothing
#
# Stack Usage:
#
# Register Convention:
########################################################
PrintExp:
	jr	$ra