; Jade Yu Cheng
; ICS 312
; Assignment 5 Exercise 2
; March 17, 2009
; The program prompt the user to enter 10 numbers between 0 and 9 (both
; included). The program prints an error message and re-prompt the user for
; another number if the number entered is invalid. These numbers are stored in
; memory as 1-byte values. The program computes a tally for each possible
; number. For instance, if the user has entered the number "3" 4 times, then
; the tally for number "3" is 4. Instead of merely printing the entered number,
; the program prints the tallies in order, with an appropriately readable format.
%include "asm_io.inc"
segment .data
prompt db "Enter a number between 0 and 9: ", 0 ; prompt msg
tally db "The tally for ", 0 ; tally msg 1
is db " is: ", 0 ; tally msg 2
invalid db "Invalid number!", 0 ; invalid msg
t db 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ; counters
segment .bss
n resb 10 ; reserve space for the numbers
segment .text
global asm_main
asm_main:
enter 0,0 ; setup
pusha ; setup
; This block of code prompts the user input in a loop and store them in n.
mov edx, 0 ; initialize edx = 0
mov ebx, n ; initialize ebx to point to the starting of n
loop_input_start:
cmp edx, 9 ; compare edx with 9
jg loop_input_end ; terminate the loop if 10 iterations are done
mov eax, prompt ; print out the message to prompt user input
call print_string
call read_int ; read a number and store it in eax
cmp eax, 0 ; compare the input with 0
jnge near else_block ; branch if the input is a negative number
cmp eax, 9 ; compare the input with 9
jnbe near else_block ; branch if the input is larger than 9
mov [ebx], al ; store the number as one byte quantity in ebx
inc edx ; increment loop count edx
inc ebx ; increment ebx to point to the next position
jmp loop_input_start
loop_input_end:
; This block of code counts the occurences of inputs and store them in t.
mov dl, 0 ; initialize edx = 0
mov ebx, n ; initialize ebx to point to the starting of n
loop_count_start:
cmp dl, 9 ; compare dl with 9
jg near loop_count_end
mov ecx, t ; let ecx points to the beginning of t
movzx eax, byte [ebx] ; extend item as a byte into eax
add ecx, eax ; move ecx ptr to a corresponding position in t
inc byte [ecx] ; increment the corresponding counter in t
inc ebx ; increment ebx to point ot the next position
inc edx ; increment edx
jmp loop_count_start
loop_count_end:
; This block of code prints out the contents of t in a formatted fashion.
mov edx, 0 ; initialize edx to be 0
mov ebx, t ; initialize ebx to point to t
loop_print_start:
cmp edx, 9 ; compare edx with 9
jg end ; terminate the loop if 10 iterations are done
mov eax, tally ; print out the first half of the message
call print_string
mov eax, edx ; print out the current iterations number
call print_int
mov eax, is ; print out the second half of the message
call print_string
mov al, [ebx] ; put the value in the address of ebx into al
movzx eax, al ; unsigned extend al to eax
call print_int ; print out the value
call print_nl
inc edx ; increment edx
inc ebx ; increment ebx to the next value in t
jmp loop_print_start
; This block of code prints out invalid input message and jump back to the
; user input loop for more inputs.
else_block:
mov eax, invalid ; print out the number invalid message
call print_string
call print_nl
jmp loop_input_start; go back to the loop for more inputs
end:
popa ; cleanup
mov eax, 0 ; cleanup
leave ; cleanup
ret ; cleanup
