+1 480 409 0818 

Processing and Storing Functions in EAX Register

implemeting functions x86 assembly

INCLUDE Irvine32.inc .DATA prompt DB "Enter a value: ",0 message DB "The absolute value is: ", 0 result DD 0 .CODE main PROC ; Print prompt for value mov edx, OFFSET prompt ; load string address call WriteString ; print the string call ReadInt ; Read a number push eax ; pass value to function call abs ; abs(value) add esp, 4 ; remove value from stack mov [result], eax ; save result in variable ; Print result message mov edx, OFFSET message ; load string address call WriteString ; print the string mov eax, [result] ; load result call WriteInt ; print the number call CrLf ; move to a new line call WaitMsg ; wait until user presses a key exit ; exit the program main ENDP ; Function abs abs PROC push ebp ; save frame pointer mov ebp, esp ; create new stack frame mov eax, DWORD PTR[ebp + 8] ; load argument value from stack cmp eax, 0 ; compare value with zero jge return ; if it's positive, return without changes neg eax ; else convert to positive by inverting the value return: pop ebp ; restore frame pointer ret ; return to caller abs ENDP END main INCLUDE Irvine32.inc .DATA prompt DB "Enter a value: ",0 oddMsg DB "The value is odd!", 0 evenMsg DB "The value is even!", 0 .CODE main PROC ; Print prompt mov edx, OFFSET prompt ; load string address call WriteString ; print the string call ReadDec ; Read a number push eax ; pass value to function call isEven ; isEven(value) add esp, 4 ; remove value from stack cmp eax, 0 ; if the return value is 0, je odd ; is odd ; else, print is even mov edx, OFFSET evenMsg ; load string address call WriteString ; print the string jmp done ; terminate program odd: ; Print is odd mov edx, OFFSET oddMsg ; load string address call WriteString ; print the string done: call CrLf ; move to a new line call WaitMsg ; wait until user presses a key exit ; exit the program main ENDP ; Function isEven isEven PROC push ebp ; save frame pointer mov ebp, esp ; create new stack frame mov eax, 0 ; return 0 by default test DWORD PTR[ebp + 8], 1 ; test stack argument lsb bit to see if the value is odd jne return ; if it's not zero, it's odd, return mov eax, 1 ; else, is even, return 1 return: pop ebp ; restore frame pointer ret ; return to caller isEven ENDP END main INCLUDE Irvine32.inc .DATA promptx DB "Enter a value for x: ",0 prompty DB "Enter a value for y: ",0 message DB "x to the y power is: ", 0 x DD 0 y DD 0 result DD 0 .CODE main PROC ; Print prompt for x mov edx, OFFSET promptx ; load string address call WriteString ; print the string call ReadDec ; Read a number mov [x], eax ; save number in variable ; Print prompt for y mov edx, OFFSET prompty ; load string address call WriteString ; print the string call ReadDec ; Read a number mov [y], eax ; save number in variable push DWORD PTR[y] ; pass y value to function push DWORD PTR[x] ; pass x value to function call power ; power(x, y) add esp, 8 ; remove x and y values from stack mov [result], eax ; save result in variable ; Print result message mov edx, OFFSET message ; load string address call WriteString ; print the string mov eax, [result] ; load result call WriteDec ; print the number call CrLf ; move to a new line call WaitMsg ; wait until user presses a key exit ; exit the program main ENDP ; Function power power PROC push ebp ; save frame pointer mov ebp, esp ; create new stack frame push ecx ; save registers push edx mov eax, 1 ; load 1 to return 1 if y is zero mov ecx, DWORD PTR[ebp + 12] ; load value of y cmp ecx, 0 ; see if y is zero je return ; if zero return 1 pow_loop: mul DWORD PTR[ebp + 8] ; multiply x by previous power loop pow_loop ; decrement y and repeat loop if y is not zero return: pop edx ; restore registers pop ecx pop ebp ; restore frame pointer ret ; return to caller power ENDP END main