macroPrintExample.asm

; Example macro with two parameters
; Implements the write system call 
; Use macro to make printing to screen more efficient
;We use times to print 20 dots under the messages
%macro write_string 2 ; start micro users two parameter message and message length
mov eax, 4 ; system call write to screen
 mov ebx, 1 ; standard out
 mov ecx, %1 ; first macro parameter message
 mov edx, %2 ; second macro parameter message size
 int 80h ; interrupt
 %endmacro ; Macro end

section .data ; data section
welcomeMsg db 'Hello, Welcome to this Simple Game',10 ; message of welcome.  Note 10 is same as endl in C++
welcomeMsgLen equ $ -welcomeMsg; welcome message length
questionMsg db 'What Letter am I thinking of: ', 10 ; Question message
questionMsgLen equ $ -questionMsg ; Length of question message
sameMsg db 'Well Done You Guessed the Letter Correctly ',10 ; Correct answer message
sameMsgLen equ $-sameMsg ; Correct Message Length
lineDot times 20 db '.' ; print one dot 20 times
cr db 10 ; newline line endl in C++

section .text ;text section where main assembly code is found
global _start ;must be declared for using gcc
_start: ;tell linker entry point
 write_string welcomeMsg, welcomeMsgLen ; call macro to print welcome message
 write_string questionMsg, questionMsgLen ; call macro to print question
 write_string sameMsg, sameMsgLen ; call macro to print correct message
 write_string lineDot, 20 ; call macro to print line of Dots
 write_string cr, 1 ; call macro to print new line like endl in C++
 
 call done ; call done function
 ; done function ends the program running
 done:
 mov eax,1 ;system call number (sys_exit) 
 int 0x80 ;call kernel