The electronic circuit can only understand 0s and 1s.
Memory: where the programs and data are kept.
Processor: Active part of the computer
Add numbers test numbers signal I/O. Also called
CPU:
Central Processor Unit
Datapath: Performs the arithmetic operations
Control:
Tells the datapath, memory and I/O devices what to do
according to the wishes of the instructions of the program.
DRAM:
Dynamic Random Access Memory, takes the same amount of
time to access the memory no matter what portion of the
memory is read.
Cache:
(a safe place for hiding things)
Consists of a small, fast memory that acts as abuffer for the
DRAMmemory
Implementation:
hardware that obeys the architecture design of
principal technique.
Instruction Set Architecture: Includes anything programmers need to
know to make a binary machine language
program work correctly, including instructions,
I/O devices and so on.
Processors and memory have improved incredibly due to the rapid
development of electronic technology.
Integrated circuit: combined dozens to millions of transistors into a
single chip.
VLSI:
Very LargScaled Integrated circuit, integrates
hundreds of thousands to millions of transistors intoa
single chip.
The manufacture of a chip begins with silicon —semiconductor
Silicon crystal ingot
↓
Sliced into wafers
↓
Chopped into dies (or chips)
5-8” diameter, 8” long
0.1” thick
Defect: Microscopic flaw in a wafer.
Any single microscopic flaw can cause failure.
Chopping wafer into dies allows us todiscard only those dies containing
the flaws, rather than the whole wafer.
Yield: Percentage of good dies from the total number of dies on the
wafer.
Since each wafer costs the same.
fewer dies means higher cost
twice the yield means half the
cost
This is the %
What is the common case?
Spending most of the time
If instruction mix
ALU
CPI = 1
Load/Store CPI = 2
60%
30%
ARMis a byte addressable machine. ARMadopts the little endian.
The immediate number is a signed number here. It can be positive,
or negative.
ß
Signed numbers to fill in, indicating how many instructions to branch over
in reaching the target instruction.
If the branch is backward, fill in a negative number. If the branch is forward,
fill in a positive number.
Branch target address is represented in PC-relative mode:
- based on where currently the branch instruction is
show the distance it branches over, rather than absolute adr.
- in terms of # of instructions
- branch forward: + positive
branch backward: - negative
:
Addressing modes:
1. Register addressing, where the operand is a register;
2. Base or displacement addressing, where the operand is at the
memory location whose address is the sum of a register and an
address in the instruction;
3. Immediate addressing, where the operand is a constant within the
instruction itself; and
4. PC-relative addressing, where the address is the sum of the PC and a
constant in the instruction.
To get the representation of a negative number
in 2’s complement:
1. Write the two’s complement of the positive
value
2. Inver all the bits
3. Add 1 to this value
Example 3: find decimal equivalent
1000 0000
Invert 0111 1111
add 1 +1
1000 0000
This means that this number is –2
(with the largest magnitude)
Example 4:
1000 0001
Invert 0111 1110
add 1 +1
0111 1111
Answer = 7x16 + F
= 127 number = -127
Please note, in the text the algorithm represented by the flowchart on the left of this
figure, and the numerical example below this figure are NOT for the hardware in this
figure! Refer to the numerical example on the next page.
IEEEStandard Floating Point Representation
Single Precession:
s
1bit
exponent
8 bits
fraction
23 bits
The exponent should be a biased exponent. The fraction should be a normalized
fraction with hidden 1. The bias for single precession is 127 ten, or 1111111two.
Given a floating point number in the “representation”, the actual number it
represents is
(–1)s x (1+ fraction) x 2 exponent −bias