Toupper

#
# An x86-32 assembly program that echos one character
#

	# declare external functions
	.extern getchar		# get one character from the console
	.extern putchar		# write one character to the console

	# declare main as global
	.global main

	# the main program
main:
	call getchar #Put first character onto %eax
	cmp $-1, %eax # Is the loop still supposed to run?
	je exit #Exit if the loop is no longer true

	push %eax
	jmp compare #Start comparing the values

output:
	call putchar #Output onto terminal
	add $4, %esp #pop the stack
	jmp main

exit:
	mov $0, %eax #reset value and end program
	ret

compare:
	cmpl $'p', (%esp)
	je toupper
	cmpl $'a', (%esp)
	je toupper
	cmpl $'u', (%esp)
	je toupper
	cmpl $'l', (%esp)
	je toupper
	cmpl $'b', (%esp)
	je toupper
	cmpl $'e', (%esp)
	je toupper
	cmpl $'n', (%esp)
	je toupper
	cmpl $'o', (%esp)
	je toupper
	cmpl $'P', (%esp)
	je tolower
	cmpl $'A', (%esp)
	je tolower
	cmpl $'U', (%esp)
	je tolower
	cmpl $'L', (%esp)
	je tolower
	cmpl $'B', (%esp)
	je tolower
	cmpl $'E', (%esp)
	je tolower
	cmpl $'N', (%esp)
	je tolower
	cmpl $'O', (%esp)
	je tolower

	jmp output

tolower:
	add $32, (%esp)
	jmp output
toupper:
	sub $32, (%esp)
	jmp output