Lecture 3: Types of Registers
There are 14 types of registers in CPU
๏ Counts, used in loop
CPU
๏ Input / output, Operations, a, ax, eax, rax
๏ Holds address of data
๏ Counts, used in loop
๏ Holds data for output
ah al
a
bh bl
bx
ch cl
cx
dh dl
dx
cs
ds
ss
es
si
di
ip
sp
f
bp
๏ Holds address of data segment
๏ Points the source operand
๏ Holds the next instruction
๏ Points current top of stack
<- Holds current status of the program
๏ Base of the top of stack
๏ Holds address of code segment
๏ Holds address of data segment
๏ Holds address of stack segment
๏ Points the destination operand
1. Accumulator
General
Purpose
Registers
Segment
Registers
Index
Registers
Special
Purpose
Registers
2. Base
3. Counter
4. Data
5. Code Segment
6. Data Segment
7. Stack segment
8. Extra segment
9. Source Index
10. Destination Index
11. Instruction Pointer
12. Stack Pointer
13. Flag registers
14. Base pointer
Stack
Add dl, bl
Add 3, bl
Add dl, 3
1
1
1
There are 14 types of registers
10101010 10101010
Low
High
X = Extended to 16 bits
E = extended to 32 bits
R = Rich Register to 64 bits
Eax Rax
ax
b, bx, ebx, rbx
cx, ecx, rcx
d, dx, edx, rdx
top
0
Carry