Page 134 - DCAP210_INTRODUCTION__TO_MICROPROCESSORS

Introduction to Microprocessors

Notes XRA: Exclusive Logical OR with Accumulator

XRI: Exclusive OR Using Immediate Data
The Compare instructions compare the content of an 8-bit value with the contents of the
accumulator;
CMP: Compare
CPI: Compare Using Immediate Data

The rotate instructions shift the contents of the accumulator one bit position to the left or right:
RLC: Rotate Accumulator Left
RRC: Rotate Accumulator Right
RAL: Rotate Left Through Carry

RAR: Rotate Right Through Carry
Complement and carry flag instructions:
CMA: Complement Accumulator

CMC: Complement Carry Flag
STC: Set Carry Flag
In 1971, the Intel 4004 processor held 2,300 transistors. In 2010, an Intel Core
processor that includes a 32nm processing die with second-generation High-k
metal gate silicon technology holds 560 million transistors.

9.4 Branching Operations

This group of instructions alters the sequence of program execution either conditionally or
unconditionally.

Jump -Conditional jumps are an important aspect of the decision-making process in the
programming. These instructions test for a certain conditions (e.g., Zero or Carry flag) and alter
the program sequence when the condition is met. In addition, the instruction set includes an
instruction called unconditional jump.

Call, Return, and Restart - These instructions change the sequence of a program either by calling
a subroutine or returning from a subroutine. The conditional Call and Return instructions also
can test condition flags.
The unconditional branching instructions are as follows:
JMP: Jump

CALL: Call
RET: Return
Conditional branching instructions examine the status of one of four condition flags to determine
whether the specified branch is to be executed. The conditions that may be specified are as follows:
NZ: Not Zero (Z = 0)
Z: Zero (Z = 1)

NC: No Carry (C = 0)
C: Carry (C = 1)

128 LOVELY PROFESSIONAL UNIVERSITY