Outline
Recap
Instruction Cycle & Pipelined Instruction Cycle
Flag Registers
Intel 8088 Microprocessor
Summary
docsity.com
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Guidelines and tips
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Instruction Cycle - Microprocessors and Computer Systems - Lecture Slides, Slides of Microprocessors
The course is to provide both theoretical background and practical skills in microcomputer (x86) system design. Both hardware and software development (assembly language) and debugging tools are included in the laboratory experiments. Key points in this lecture are: Instruction Cycle, Recap, Instruction Cycle and Pipelined Instruction Cycle, Flag Registers, Intel 8088 Microprocessor, Microprocessor, Types of Buses, Binary Computation, Binary Addition, Binary Subtraction
Typology: Slides
2012/2013
1 / 24
This page cannot be seen from the preview
Don't miss anything!
Related documents
Partial preview of the text
Download Instruction Cycle - Microprocessors and Computer Systems - Lecture Slides and more Slides Microprocessors in PDF only on Docsity!
Outline
Recap
Instruction Cycle & Pipelined Instruction Cycle
Flag Registers
Intel 8088 Microprocessor
Summary
Recap
Buses
Parallel signal lines connecting CPU with I/OPorts and memory
Types of Buses:^
Address bus
Data bus
Control bus
Instruction Cycle
Instruction Pointer (IP)
One register on CPU used to store theaddress of the upcoming instruction
Fetch Cycle
Send address of IP onto the address busand get the instruction from the data bus
Execute Cycle
Decode and execute the instruction
Instruction Cycle Structure
Bus Interface Unit (BIU)
Respond to all signals that go to the processor
Store the instruction code in instruction queue,enable
pipelined processing of instructions
Execution Unit (EU)
Select the registers to operate on and docomputation in arithmetic logic unit (ALU)
Test the
status and control flags
, update the
results to registers
Pipelined Instruction Cycle
The approach to speed up the instructionscycle processing in microprocessors.
Divide a complex and time-consuming task intoseveral small and single steps to improve thetask processing.
How Pipelined Instruction Cycle works?Think about the “laundry” example:
Doing N loads of laundry, once at a time^ The fact is, doing one load at a time is not smart!
Doing N loads of laundry in
“
pipeline
”
“Pipeline” is a more effective way!
A 16-bit flag register indicates some conditionsproduced by the execution of instruction or controlscertain operations of the EU
Flag Registers
Flag Registers (Con
’
t)
A flag indicates the result has exceeded the range of thesigned number in the machine.
For a 8-bit system, the range of signed number is:
7
7
-1, i.e. -128~0~+
If the result is out of this range, then Overflow!
Overflow Flag
Methods to judge “Overflow” :
Judge in Decimal Number,
1000 1000=-1201100 0100=-60(-120)+(-60)=(-180)>(-128), overflow!
The overflow only can be caused by the addition of twopositive numbers or negative numbers.Judge Rule: If the addend and augend have the samesign bit, while the sign bit of the result is different, thenOverflow! 1000 1000 and 1100 0100 are negative,the sum 0100 1100 is positive, Overflow!
Overflow Flag (Con
’
t)
Intel 8088 Chip with different pins
8088’s Input & Output
Input
Output
DC Characteristic