Logical Group Of Instruction

By

ANA

ORA

XRA

ANI

ORI

XRI

CMP

CPI 

RLC

RRC

RAL

RAR

CMA

CMC

STC

 

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RRC

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  Syntax: RRC   Byte: 1byte   Addressing Mode: Implicit Addressing Working:  1. This is one byte instruction. 2. Microproccessor will allocate one byte for opcode RRC and operand is Accumulator i.e. operand will not need memory allocation during execution. 3. Thi s instruction rotates content of Accumulator one bit position towards Right.   i.e. The bit A0 is stored  in carry flag AS WELL AS  will get stored in A7 bit position.   4. C Flag will get affected. Example: RRC   where   [A]= 21H After execution of RRC [A] = 90H     A= 21 =  0010 0001 A7 ->  A6 -> A5 -> A4 -> A3 -> A2 -> A1 -> A0   -> Cy    |___<-____________________________<-_ __| 0         0         1        0       0        ...
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ANI

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  Syntax: ANI 8-bit Where 8- bit is an immediate operand data. Byte: 2byte Addressing Mode: Immediate Addressing Working:  1.This is 2 byte instruction. 2. Microprocessor will allocate first byte for opcode and second byte for immediate data. 3. During execution of this instruction, microprocessor will perform Logical ANDing operation between content of Accumulator and Immediate data. 4. S, Z and  P  are modified . Cy is reset(Cy=0) and Ac is set (Ac=1) . Example: ANI 22H where [A]= 11H After execution of ANI 22H [A] = 00H     A= 11 =  0001 0001  =  22 =  0010 0010  A=00    0000  0000 FLAG=  01 0 1 0 0 0 0 = 50H
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CMP

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  Syntax: CMP R Where R can be any of the general purpose registers (A,B,C,D,E,H and L) Byte: 1byte Addressing Mode: Register   Addressing Working:  1. This is one byte instruction. 2. microprocessor will allocate one byte for opcode CMP and operands are registers i.e. operands don't need memory allocations for execution here. 3. T his instruction compares the content of the register R with content of the Accumulator. The comparison is done using subtraction of the content of register from the Accumulator .  The content of Accumulator remains unchanged . Conditions of Comarison:   1.  If [A] < [R] then Cy flag is set i.e. Cy =1 . 2. If [A] = [R]  then Z flag is set i.e Z=1. 3. If [A] > [R]  then Cy and Z flags are reset. i.e Cy = 0 and  Z = 0 4. Flag Example: CMP B where  [B] = 22H  and [A]= 11H After execution of CMP B [A] = 11H [B] = 22H   2's complement subtraction: A= 11 =  0001 0001 B= 22 =  0010 0010 1'...
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