Format: MUL SRC

Actions performed:

Byte operand: (AX)←(AL)*(SRC)

Word operand: (DX, AX)←(AX)*(SRC)

Double-word operand: (EDX, EAX)←(EAX)*(SRC)

Mul:80c 5 1 There is only one instruction in the multiplication instruction of the single chip microcomputer system:

MUL AB

The multiplication instruction is used to multiply two unsigned 8-bit binary numbers in A and B. The lower 8 bits of the product of 16 bits are stored in A and the upper 8 bits are stored in B. If the product is greater than 256, that is, the upper B is not 0, then OV is set to1; Otherwise, OV is cleared and CY is always cleared.

For example, let (A)=50H(80) and (B)=0A0H( 160).

If MUL AB is executed,

The implementation result is:

The product is 3200H( 12800).

(A)=00H，(B)=32H，(OV)= 1，(CY)=0

The function of the following program is to input the values of x and y for many times and find the sum of x and y.

int mul(int a，int b)

{

? int c = 0；

? c = a+b；

? Return to c;

}