Which flags does the CMP instruction change?

Which flags does the CMP instruction change?

After operation between operands, result is always stored in first operand. CMP and TEST instructions affect flags only and do not store a result (these instruction are used to make decisions during program execution). These instructions affect these flags only: CF, ZF, SF, OF, PF, AF.

Which of the following flags will be affected by CMP instruction?

The four flags that the CMP instruction can set – Z,O,C, and S, are known as the zero, overflow, carry, and sign flags respectively. The zero flag is set whenever the result of the subtraction is equal to zero. This, of course, only occurs when the operands are equal.

Does CMP change carry flag?

There are six flags which are used to indicate the result of certain instructions. Some instructions such as CMP, TEST and BT only alter some of these flags and do nothing else. Other instructions carry out other operations but also alter some of the flags. Some instructions don’t alter the flags at all.

How does CMP instructions work?

The CMP instruction compares two operands. It is generally used in conditional execution. This instruction basically subtracts one operand from the other for comparing whether the operands are equal or not. It does not disturb the destination or source operands.

What is difference between CMP and test instruction?

The TEST instruction performs an implied AND operation between corresponding bits in the two operands and sets the flags without modifying either operand. reg, mem, and immed can be 8, 16, or 32 bits. The CMP instruction sets the flags as if it had performed subtraction on the operand.

What is the difference between CMP and sub instruction?

What is the difference between CMP and sub instruction? CMP is used for comparing 2 registers by subtraction them from one another, but answer is not saved, whereas SUB subtracts 2 registers and saves the answer.

What is the difference between test and CMP?

What is the difference between CMP and sub instructions?

Explanation: The cmp is used for comparing the numeric value with the source value to the destination value in the Microprocessor 8086 Where as sub is used for subtract the source value to the destination numeric value in the Microprocessor 8086.

What does CMP do?

A comprehensive metabolic panel (CMP) is a test that measures 14 different substances in your blood. It provides important information about your body’s chemical balance and metabolism. Metabolism is the process of how the body uses food and energy.

How are flags set in a CMP instruction?

CMP instruction sets status flags according to the comparisons between the arguments. See : wikipedia’s FLAGS page The importance of CMP applies mostly in conditional code execution (Jump – See : assembly_conditions ).

When to use flags register in conditional jump?

However, the flags register is updated and can be used in a conditional jump, like jump-if-equal ( JE ), most often as the next instruction after the cmp. The advantage over other instructions is that you can compare two values without destroying any of them.

How is the conditional jump instruction used in CMP?

It is used along with the conditional jump instruction for decision making. CMP compares two numeric data fields. The destination operand could be either in register or in memory. The source operand could be a constant (immediate) data, register or memory. CMP DX, 00 ; Compare the DX value with zero JE L7 ; If yes, then jump to label L7 . .

How does the BNE instruction in CMP work?

The code works because cmp sets some global flags indicating various properties of the operation. The bne instruction — which is really just a b (branch) with a ne condition code suffix — reads these flags to determine whether or not to branch 1. The following code implements a more efficient solution: