Hi, I'm a student in assembly. I'm using NASM and running Ubuntu Linux. For our assignment we need to use subprograms, loops, stacks, and arrays. We are supposed to get a positive integer, find all the factors, put each factor onto an array, load the array onto the stack, then output the factors in decreasing order from original positive integer to 1. Unfortunately, the tutors at my school are clueless about assembly and even my teacher is frustrated with assembly and refuses to look at code. I'm having several problems. Currently, I get a return value of 1, which could be the factor 1 or the index of the array. I understand loops, but I'm lost with stacks and arrays. Also, the program runs in an infinite loop, how can I solve this?
welcome db "Welcome to Randy Brummett's friendly factorization program", 0
prompt db "Please enter a positive integer: ", 0
output db "The factors of ", 0
are db " are ", 0
comma db ", ", 0
repeat db "Do you have more inputs (Y or N)? ", 0
bye db "Have a nice day. Bye.", 0
;
; Uninitialized data are placed in the .bss segment
;
segment .bss
;
;
; ======= Place uninitialized data here
;
myint resd 1 ; positive integer to be factored
divisor resd 1 ; divisor
factorarray resd 34 ; array for factors
;
; Code is put into the .text segment
;
segment .text
global asm_main ; declare _asm_main if compiling on Windows
asm_main: ; delcare _asm_main if compiling on Windows
enter 0,0 ; setup routine
pusha ; push all registers on the system stack
;
; Begin execution area
;
;
;
;
; ======== Place executing instructions here
;
;
mov [ebx], factorarray ; ebx = address of factorarray
call getinput ; getinput subprogram
call factorization
call displayfactors ; displayfactors subprogram
getinput: ; begin subprogram
mov eax, welcome ; displays welcome message
call print_string ; print prompt
call print_nl ; new line
mov eax, prompt ; prompts for input
call print_string ; print prompt
call read_int ; read integer
mov [myint], eax ; store into int
ret ; end subprogram
factorization: ; begin subprogram
mov dword [divisor], myint ; store integer into divisor
mov dword [factorarray], divisor ; put positive integer as a factor in array
findfactors: ; begin loop
cmp dword [divisor], 1 ; if divisor = 1 quit, else continue
jz endif ; quit
sub dword [divisor], 1 ; divisor - 1
mov eax, [myint] ; put dividend into eax
mov ecx, [divisor] ; put divisor into ecx
mov edx, 0 ; initialize edx to 0
div ecx ; divide
cmp edx, 0 ; if remainder = 0 add integer into array, else check next divisor
jz addarray ; add divisor to array
jnz findfactors ; check other divisors if they are factors
loop findfactors ; end loop
addarray: ; begin addarray
mov eax, [divisor] ; put divisor into eax
mov dword [factorarray], eax ; store factor into array
add ebx, 4 ; increment array
jmp findfactors ; jump to findfactors to find more factors
endif: ; quit subprogram
push dword factorarray ; push array onto stack
pop eax ; pop array so no seg fault
ret ; end subprogram
displayfactors:
mov eax, output ; display output message
call print_string ; print
mov eax, [myint] ; display positive integer from user
call print_int ; print
mov eax, are ; display message "are"
call print_string ; print
mov eax, [factorarray]
ret ; end subprogram