Използвам Project Euler, за да науча MIPS, по-специално използвам проблем 6, за да науча как да използвам подпрограма. За съжаление, правя нещо много грешно, защото отговорът ми, който получавам, е твърде голям по величина. Проблемът ми тук ли е с начина, по който използвам подпрограмата, или е нещо съвсем друго?
## p6.asm
##
## Andrew Levenson, 2010
## Project Euler, Problem 6
##
## Calculate the difference
## between the sum of the squares
## and the square of the sum
## of all natural numbers n
## such that n < 1000
.text
.globl main
main:
init:
## Registers
ori $t0, $0, 0x0 # $t0 will be used for scratch
ori $t1, $0, 0x0 # $t1 is the loop counter and n
ori $t2, $0, 0x0 # $t2 will be the sum of the squares
ori $t3, $0, 0x0 # $t3 will be the square of the sum
ori $t4, $0, 0x3E8 # $t4 = 1000, the limit
loop:
## Main loop
addiu $t1, $t1, 0x1 # Increment n
sltu $t0, $t1, $t4 # Is n less than 1000?
beq $t0, $0, diff # if $t0 == 0 then jump to diff
sll $0, $0, $0 # no op
addu $t3, $t3, $t1 # sum = sum + n
move $a0, $t1 # put n in $a0
jal square # jump to square and save position to $ra
sll $0, $0, $0 # no op
addu $t2, $t2, $a0 # The sum of the squares =
# sum + n **2
j loop # jump to loop
sll $0, $0, $0 # no op
square:
## Subroutine that squares a given number
mul $a0, $a0, $a0 # Argument = Argument ** 2
jr $ra # jump to $ra
# $ra = instruction where jal was called
sll $0, $0, $0 # no op
diff:
## Finds the difference of $t2 and $t3
## But first, we have to square $t3
move $a0, $t3 # puts $t3 in $a0
jal square # jump to square and save position to $ra
sll $0, $0, $0 # no op
move $t3, $a0 # $t3 = $a0 = $t3 ** 2
subu $t0, $t2, $t3 # $t0 = $t2 - $t3
print:
li $v0, 0x1 # system call #1 - print int
move $a0, $t0
syscall # execute
li $v0, 0xA # system call #10 - exit
syscall
## End of Program
