Instruction type XRI d8 in 8085 Microprocessor

Microprocessor8085

In 8085 Instruction set, XRI is a mnemonic that stands for “eXclusive OR Immediate with Accumulator” and “d8” stands for any 8-bit data. This instruction is used to Ex-OR 8-bit immediate data with the Accumulator. The result of Ex-ORing will be stored in the Accumulator overwriting its previous content. As it is a Logical instruction, so S, P, and Z flags are affected based on the result thus produced. Cy and AC are reset to 0. It occupies 2-Bytes in memory during execution.

Mnemonics, Operand Opcode(in HEX) Bytes
XRI Data EE 2

Let us consider XRI CDH as an example instruction of this category. As it is a 2-Byte instruction so it will occupy 2 consecutive memory locations. We are considering initial content of Accumulator is ABH. The result of execution of this instruction has been shown in the following tracing table −

Before After

(A)

ABH 66H

(F)

Any values Cy=0,AC=0,S=0,P=1,Z=0

The internal calculation has been done as shown below −

(A) ABH ---> 1010 1011
(d8) CDH ---> 1100 1101
               ---------
      XRICDH --->0110 0110 (66H)

Address Hex Codes Mnemonic Comment
2002 EE XRI CDH A = A XOR CDH
2003 CD Operand CDH

The timing diagram against this instruction XRI CDH execution is as follows.

XRI CDH

Summary − So this instruction ORI CDH requires 2-Bytes, 2-Machine Cycles (Opcode Fetch, Memory Read) and 7 T-States for execution as shown in the timing diagram.

raja
Published on 04-Dec-2018 12:16:03
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