CS 456 - Systems Programming Spring 2024

Displaying ./code/asm/helloworld-input.asm

; Hello World Program (Getting input)
; Compile with: nasm -f elf helloworld-input.asm
; Link with (64 bit systems require elf_i386 option): ld -m elf_i386 helloworld-input.o -o helloworld-input
; Run with: ./helloworld-input
 
%include        'functions.asm'
 
SECTION .data
msg1        db      'Please enter your name: ', 0h      ; message string asking user for input
msg2        db      'Hello, ', 0h                       ; message string to use after user has entered their name
 
SECTION .bss
sinput:     resb    255                                 ; reserve a 255 byte space in memory for the users input string
 
SECTION .text
global  _start
 
_start:
 
    mov     eax, msg1
    call    sprint
 
    mov     edx, 255        ; number of bytes to read
    mov     ecx, sinput     ; reserved space to store our input (known as a buffer)
    mov     ebx, 0          ; read from the STDIN file
    mov     eax, 3          ; invoke SYS_READ (kernel opcode 3)
    int     80h
 
    mov     eax, msg2
    call    sprint
 
    mov     eax, sinput     ; move our buffer into eax (Note: input contains a linefeed)
    call    sprint          ; call our print function
 
    call    quit