School Commit Init

Anul 1/Semestrul 1/ASC/Seminar 2/ex4/ex4.asm

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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
+    ; ...
+    a db 10
+    b dw 2
+    c dd 3 
+    d db 4
+    f dw 1
+    g dw 2
+    x dq 2
+    
+    
+
+; our code starts here
+segment code use32 class=code
+    start:
+        ; ...
+        mov al,[a]          ;AL=a
+        cbw                 ;AX=a
+        imul word [b]       ;DX:AX=a*b
+        push dx             ;stack: dx,
+        push ax             ;stack: dx,ax
+        mov al,[d]          ;AL=d
+        cbw                 ;AX=d
+        cwde                ;EAX=d
+        mov ecx,[c]         ;ECX=c
+        sub ecx,eax         ;ECX=c-d
+        pop eax             ;EAX=a*b , stack:
+        cdq                 ;EDX:EAX=a*b
+        idiv dword ecx      ;EAX=(a*b)/(c-d)
+        mov ecx,eax         ;ECX=(a*b)/(c-d)
+        mov ax,[f]          ;AX=f
+        imul word [g]       ;DX:AX=f*g
+        push dx             ;stack: DX
+        push ax             ;stack: DX,AX
+        pop eax             ;EAX=f*g , stack:
+        add eax,ecx         ;EAX=(a*b)/(c-d)+f*g
+        cdq                 ;EDX:EAX=(a*b)/(c-d)+f*g
+        add [x],eax
+        adc [x+4],edx
+        
+        
+    
+        ; exit(0)
+        push    dword 0      ; push the parameter for exit onto the stack
+        call    [exit]       ; call exit to terminate the program