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)
+
+
+;Given a byte string S of length l, obtain the string D of length l-1 as D(i) = S(i) * S(i+1) (each element of D is the product of two consecutive elements of S).
+
+
+segment data use32 class=data
+    ; ...
+    S db 1,2,3,4
+    l equ $-S
+    D resw l-1
+
+; our code starts here
+segment code use32 class=code
+    start:
+        ; ...
+        ; mov ECX,0
+        ; jmp_label:
+            ; mov AL,[S+ECX]
+            ; mov BL,[S+ECX+1]
+            ; imul BL
+            ; mov [D+2*ECX],AX
+            ; inc ECX
+            ; cmp ECX,l-1
+            ; jb jmp_label
+            
+        mov ECX,l
+        mov ESI,0
+        jmp_label:
+            mov AL,[S+ESI]
+            mov BL,[S+ESI+1]
+            imul BL
+            mov [D+2*ESI],AX
+            inc ESI
+            loop jmp_label
+            
+           
+        ; exit(0)
+        push    dword 0      ; push the parameter for exit onto the stack
+        call    [exit]       ; call exit to terminate the program