School Commit Init

2024-08-31 12:07:21 +03:00
commit 0b130ee18c
2801 changed files with 4720552 additions and 0 deletions
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+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
+    ; ...
+    s1 db 12h,78h
+    l1 equ $-s1
+    s2 db 34h,0ABh
+    l2 equ $-s2
+    s3 resb l1+l2
+    l3 equ $-s3
+; our code starts here
+segment code use32 class=code
+    start:
+        ; ...
+        mov ECX,l3
+        mov ESI,0
+        mov EDX,0
+        mov EDI,s3
+        cld
+        
+        label:
+            mov AL,0FFh
+            cmp ESI,l1
+            jge a
+            mov AL,[s1+ESI]
+            a:
+            mov BL,0FFh
+            cmp EDX,l1
+            jge b
+            mov BL,[s2+EDX]
+            b:
+            cmp AL,BL
+            jb less
+            mov AL,BL
+            inc EDX
+            STOSB
+            dec ECX
+            jmp comp
+            less:
+            inc ESI
+            dec ECX
+            STOSB
+            jmp comp
+            comp:
+                cmp ECX,0
+                jg label
+               
+        ; exit(0)
+        push    dword 0      ; push the parameter for exit onto the stack
+        call    [exit]       ; call exit to terminate the program