1. Principles of Computers 14th Lecture
Pavel Ježek, Ph.D.

2. Examples of CPU Architectures
CPU name
Physical address width
8-bit
6502
MOS 6502
16-bit
(64 kB)
Apple I (1976)
Apple II (1977)
Atari 800 (1979)

3. Examples of CPU Architectures
CPU name
Current instruction
register(s)
Physical address width
8-bit
6502
MOS 6502 PC
16-bit
(64 kB)
PC = program counter
Apple I (1976)
Apple II (1977)
Atari 800 (1979)

4. Examples of CPU Architectures
CPU name
Current instruction
register(s)
Physical address width
8-bit
6502
MOS 6502 PC
16-bit
(64 kB)
x86-16
x86
Intel 8088
20-bit
(1 MB)
Intel 8086
Apple I (1976)
Apple II (1977)
Atari 800 (1979)
IBM PC (1981)

5. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
20-bit
(1 MB)
Intel 8086
IBM PC (1981)

6. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
20-bit
(1 MB)
Intel 8086
IBM PC (1981)
logical address (16 bit & 16 bit):
Segment:Offset

7. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
20-bit
(1 MB)
Intel 8086
IBM PC (1981)
logical address (16 bit & 16 bit):
Segment:Offset
physical address (20 bit):
(Segment * 16) + Offset

8. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
20-bit
(1 MB)
Intel 8086
IBM PC (1981)
logical address (16 bit & 16 bit):
Segment:Offset
physical address (20 bit):
(Segment * 16) + Offset
logical address:
$AAAA:$0000
physical address:
$AAAA * 16 = $AAAA shl 4 = $AAAA0 +
$0000 =
$AAAA0

9. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
20-bit
(1 MB)
Intel 8086
IBM PC (1981)
logical address (16 bit & 16 bit):
Segment:Offset
physical address (20 bit):
(Segment * 16) + Offset
logical address:
$AAAA:$0000
physical address:
$AAAA * 16 = $AAAA shl 4 = $AAAA0 +
$0000 =
$AAAA0
logical address:
$A000:$AAA0
physical address:
$A000 * 16 = $A000 shl 4 = $A0000 +
$AAA0 =
$AAAA0

10. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
20-bit
(1 MB)
Intel 8086
IBM PC (1981)
logical address (16 bit & 16 bit):
Segment:Offset
physical address (20 bit):
(Segment * 16) + Offset
logical address:
$AAAA:$0000
physical address:
$AAAA * 16 = $AAAA shl 4 = $AAAA0 +
$0000 =
$AAAA0
logical address:
$A100:$9AA0
physical address:
$A100 * 16 = $A100 shl 4 = $A1000 +
$9AA0 =
$AAAA0
logical address:
$A000:$AAA0
physical address:
$A000 * 16 = $A000 shl 4 = $A0000 +
$AAA0 =
$AAAA0

11. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
20-bit
(1 MB)
Intel 8086
IBM PC (1981)
logical address (16 bit & 16 bit):
Segment:Offset
physical address (20 bit):
(Segment * 16) + Offset
Address space aliasing
logical address:
$AAAA:$0000
physical address:
$AAAA * 16 = $AAAA shl 4 = $AAAA0 +
$0000 =
$AAAA0
logical address:
$A100:$9AA0
physical address:
$A100 * 16 = $A100 shl 4 = $A1000 +
$9AA0 =
$AAAA0
logical address:
$A000:$AAA0
physical address:
$A000 * 16 = $A000 shl 4 = $A0000 +
$AAA0 =
$AAAA0

12. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
PC = program counter
x86-16
x86
Intel 8088
bit
CS:IP
20-bit
(1 MB)
CS = code segment
IP = instruction pointer
Intel 8086
IBM PC (1981)
logical address (16 bit & 16 bit):
Segment:Offset
physical address (20 bit):
(Segment * 16) + Offset
Address space aliasing
logical address:
$AAAA:$0000
physical address:
$AAAA * 16 = $AAAA shl 4 = $AAAA0 +
$0000 =
$AAAA0
logical address:
$A100:$9AA0
physical address:
$A100 * 16 = $A100 shl 4 = $A1000 +
$9AA0 =
$AAAA0
logical address:
$A000:$AAA0
physical address:
$A000 * 16 = $A000 shl 4 = $A0000 +
$AAA0 =
$AAAA0

13. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
CS:IP
20-bit
(1 MB)
Intel 8086
IBM PC (1981)

14. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
Special mode
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
CS:IP
20-bit
(1 MB)
Intel 8086
Intel 80286
24-bit
(16 MB)
protected 16
(+ real) mode

15. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
Special mode
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
CS:IP
20-bit
(1 MB)
Intel 8086
Intel 80286
24-bit
(16 MB)
protected 16
(+ real) mode
32-bit
IA-32
INTEL32
Intel 80386
EIP
(4 GB)
protected 32
mode

16. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
Special mode
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
CS:IP
20-bit
(1 MB)
Intel 8086
Intel 80286
24-bit
(16 MB)
protected 16
(+ real) mode
32-bit
IA-32
INTEL32
Intel 80386
EIP
(4 GB)
protected 32
mode
Intel Pentium Pro
36-bit
(64 GB)
PAE (Physical Address Extension)

17. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
Special mode
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
CS:IP
20-bit
(1 MB)
Intel 8086
Intel 80286
24-bit
(16 MB)
protected 16
(+ real) mode
32-bit
IA-32
INTEL32
Intel 80386
EIP
(4 GB)
protected 32
mode
Intel Pentium Pro
36-bit
(64 GB)
PAE
64-bit
x64
x86-64
AMD64
INTEL64
EM64T
AMD Opteron
(Intel Pentium 4)
RIP
40-bit
(1 TB)
long mode

18. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
Special mode
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
CS:IP
20-bit
(1 MB)
Intel 8086
Intel 80286
24-bit
(16 MB)
protected 16
(+ real) mode
32-bit
IA-32
INTEL32
Intel 80386
EIP
(4 GB)
protected 32
mode
Intel Pentium Pro
36-bit
(64 GB)
PAE
64-bit
x64
x86-64
AMD64
INTEL64
EM64T
AMD Opteron
(Intel Pentium 4)
RIP
40-bit
(1 TB)
long mode
2018 current
(e.g. Core i7)
AMD: 48b → 256 TB
Intel: 46b → 64 TB

19. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
Special mode
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
CS:IP
20-bit
(1 MB)
Intel 8086
Intel 80286
24-bit
(16 MB)
protected 16
(+ real) mode
32-bit
IA-32
INTEL32
Intel 80386
EIP
(4 GB)
protected 32
mode
Intel Pentium Pro
36-bit
(64 GB)
PAE
64-bit
x64
x86-64
AMD64
INTEL64
EM64T
AMD Opteron
(Intel Pentium 4)
RIP
40-bit
(1 TB)
long mode
2018 current
(e.g. Core i7)
AMD: 48b → 256 TB
Intel: 46b → 64 TB
32-bit ARM
64-bit ARM
32b MIPS
MIPS64
PowerPC (PPC)
32b Motorola (68k)

20. Examples of CPU Architectures
CPU name
Logical address width
Current instruction
register(s)
Physical address width
Special mode
8-bit
6502
MOS 6502
16-bit PC
(64 kB)
x86-16
x86
Intel 8088
bit
CS:IP
20-bit
(1 MB)
Intel 8086
Intel 80286
24-bit
(16 MB)
protected 16
(+ real) mode
32-bit
IA-32
INTEL32
Intel 80386
EIP
(4 GB)
protected 32
mode
Intel Pentium Pro
36-bit
(64 GB)
PAE
64-bit
x64
x86-64
AMD64
INTEL64
EM64T
AMD Opteron
(Intel Pentium 4)
RIP
40-bit
(1 TB)
long mode
2018 current
(e.g. Core i7)
AMD: 48b → 256 TB
Intel: 46b → 64 TB
32-bit ARM
64-bit ARM
32b MIPS
MIPS64
PowerPC (PPC)
32b Motorola (68k)