School Commit Init

2024-08-31 12:07:21 +03:00
commit 0b130ee18c
2801 changed files with 4720552 additions and 0 deletions
@@ -0,0 +1,32 @@
+bits 32 ; assembling for the 32 bits architecture
+
+; declare the EntryPoint (a label defining the very first instruction of the program)
+global start        
+
+; declare external functions needed by our program
+extern exit               ; tell nasm that exit exists even if we won't be defining it
+import exit msvcrt.dll    ; exit is a function that ends the calling process. It is defined in msvcrt.dll
+                          ; msvcrt.dll contains exit, printf and all the other important C-runtime specific functions
+
+; our data is declared here (the variables needed by our program)
+segment data use32 class=data
+    ; ...
+    a db 'message'
+    l equ $-a
+    b resb l
+
+; our code starts here
+segment code use32 class=code
+    start:
+        ; ...
+        mov ESI,l
+        label:
+        mov AL,[a+ESI-1]
+        
+        sub AL,'a'-'A'
+        mov [b+ESI-1],AL
+        dec ESI
+        jne label
+        ; exit(0)
+        push    dword 0      ; push the parameter for exit onto the stack
+        call    [exit]       ; call exit to terminate the program