first commit

calculator.s

@@ -0,0 +1,70 @@
+; -- Assembly Calculator ---------------------------------------
+;								
+; This project is a practice for my low-level programming study	
+; --------------------------------------------------------------
+
+; x86_64 linux syscalls table
+;
+; 0: read	(needs fd, where to save and length)
+; 1: write 	(needs fd, string and string length)
+; 60: exit	(needs status code)
+
+global _start
+
+section .bss
+    fnum resb 128
+    snum resb 128
+
+; "variables" read-only
+section .rodata
+    title db "Assembly Calculator v1.0 by /synt-xerror", 0xA
+    titlel equ $ - title
+    
+    fir db 0xA, "Enter the first number: "
+    firl equ $ - fir
+    
+    sec db "Enter the second number: "
+    secl equ $ - sec
+
+section .text
+
+_start:
+    ; print title
+    mov rax, 1
+    mov rdi, 1
+    mov rsi, title
+    mov rdx, titlel
+    syscall
+
+    ; ask to enter first number
+    mov rax, 1
+    mov rdi, 1
+    mov rsi, fir
+    mov rdx, firl
+    syscall
+    
+    ; input to enter the first number
+    mov rax, 0
+    mov rdi, 0
+    mov rsi, fnum
+    mov rdx, 128
+    syscall
+
+    ; ask to enter second number
+    mov rax, 1
+    mov rdi, 1
+    mov rsi, sec
+    mov rdx, secl
+    syscall
+
+    ; input to enter the second number
+    mov rax, 0
+    mov rdi, 0
+    mov rsi, snum
+    mov rdx, 128
+    syscall
+
+    ; exit
+    mov rax, 60
+    mov rdi, 0
+    syscall