Continuing, write assembly language instructions—not a complete program—that imp

Question

Continuing, write assembly language instructions—not a complete program—that implements line 4 of this C code (where the variables a, b, c, d, w, x, y, and z on line 1 were defined in the data section of Exercise 2). [01] int a = 0x1234, b = 0x4321, c = 0xCA51, d = 0xA5A5, w = 0, x = 0, y = 0, z = 0; [02] int main() [03] { [04] w = (a & b) ^ ~(c | d); // ^ is the exclusive-or operator [08] return 0; [09] } Line 4 requires 13 assembly language instructions, including the instructions that load the addresses and values of the variables into registers and the instruction that writes the result to the memory location allocated to w. For full credit, write a comment for each instruction explaining what the instruction is doing. Hint: ~(c | d) is c NOR d.

Explanation / Answer

;This program define 4 variables a,b,c,d with respective values in data segment
;it use 4 register AX,BX, CX, DX which loads the values from variables a,b,c,d
; after loading the data it perform and operation on variable A and B store result in AX
; then perform or opearion on C and D, store result in CX register
; then perform not operation on the data stored in CX register
; finally prfrome XOR operaton on the registers AX, CX and store result in AX
; store the final result in variable w

MOV AX, [A]            ;fetch the data from memory location A and store in register AX
MOV BX, [B]       ;fetch the data from memory location B and store in register BX
AND AX,BX       ;perform A=(A & B)

MOV CX,[C]       ;fetch the data from memory location C and store in register CX
MOV DX,[D]       ;fetch the data from memory location C and store in register DX
OR CX,DX       ;perform C= (C|D)
NOT CX           ;perform ~(C|D)

XOR AX,CX       ;Perform (A & B) ^ ~ (C |D)

MOV [W],AX       ;Store the result of operation at memory location W

; Data Section

A DW 1234h    ;define A variable with value 0x1234
B DW 4321h    ;define B variable with value 0x4321
C DW CA51   ;define C variable with value 0xCA51
D DW A5A5h   ;define D variable with value 0xA5A5

W DW 1256   ;define the location number for variable w

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