6.The last four lines contain incidental information about the execution of the instruction. The num- ber of machine cycles and states required to exe- cute the instruction are listed first. If the instruc- tion has two possible execution times, as in a Conditional Jump·, both times will be listed, sep- arated by a slash. Next, any significant data ad- dressing modes' (see Page 4-2) are listed. The last line lists any of the five Flags that are affected by the execution of the instruction.

MVI r, data (Move Immediate)

(r) ~ (byte 2)

The content of byte 2 of the instruction is moved to register r.

Data Transfer Group:

This group of instructions transfers data to and from registers and memory. Condition flags are not affected by any instruction in this group.

MOV r1, r2 (Move Register)

(r1)"'-(r2)

The content of register r2 is moved to register r1.

0 I

D I D I D

S

S I S

 

'.1

f'

1

 

. \

 

 

Cyc·'es:

 

 

 

 

States:

5

 

 

 

Addressing:

register

 

 

 

Flags:

none

 

 

MOV r, M (Move from memory)

(r)~ ((H) (L))

The content of the memory location, whose address is in registers Hand L, is moved to register r.

1 I I 0

Cycles:

2

States:

7

Addressi ng:

reg. indirect

Flags:

none

MOV M, r (Move to memory)

((H)(L))~ (r)

The content of register r is moved to the memory lo- cation whose address is in registers Hand L.

o ' 1 I

Cycles: 2

States: 7

Addressing: reg. indirect

Flags: none

MVI M, data (Move to memory immediate) ((H) (L)) ~ (byte 2)

The content of byte 2 of the instruction is moved to the memory location whose address is in registers H and L.

o I 0

o

1 ' 1 I 0

data

 

 

Cycles:

3

 

States:

10

 

Addressing:

immed.lreg. indirect

Flags:

none

 

LXI rp, data 16 (Load register pair immediate) (rh) ~ (byte 3),

(rl) ~ (byte 2)

Byte 3 of the instruction is moved into the high-order register (rh) of the register pair rp. Byte 2 of the in- struction is moved into the low-order register (rl) of the register pair rp.

o I o I R 1 p I o I o I o I 1

low-order data

high-order data

Cycles: 3

States: 10

Addressing: immediate

Flags: none

4-4

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Image 48
Intel 8080 Data Transfer Group, MOV r1, r2 Move Register, Content of register r2 is moved to register r1, Reg. indirect
Page 47 Page 49

8080 specifications

The Intel 8085 and 8080 microprocessors were groundbreaking innovations in the world of computing, paving the way for future microprocessor development and personal computing.

The Intel 8080, introduced in 1974, was an 8-bit microprocessor that played a fundamental role in the early days of personal computing. With a 16-bit address bus, it had the capability to address 64 KB of memory. Running at clock speeds of 2 MHz, the 8080 was notable for its instruction set, which included 78 instructions and 246 opcodes. It supported a range of addressing modes including direct, indirect, and register addressing. The 8080 was compatible with a variety of peripherals and played a crucial role in the development of many early computers.

The microprocessor's architecture was based on a simple and efficient design, making it accessible for hobbyists and engineers alike. It included an 8-bit accumulator, which allowed for data manipulation and storage during processing. Additionally, the 8080 featured registers like the program counter and stack pointer, which facilitated program flow control and data management. Its ability to handle interrupts also made it suitable for multitasking applications.

The Intel 8085, introduced in 1976, was an enhancement of the 8080 microprocessor. It maintained a similar architecture but included several key improvements. Notably, the 8085 had a built-in clock oscillator, simplifying system design by eliminating the need for external clock circuitry. It also featured a 5-bit control signal for status line management, which allowed for more flexible interfacing with peripheral devices. The 8085 was capable of running at speeds of up to 3 MHz and had an extended instruction set with 74 instructions.

One of the standout features of the 8085 was its support for 5 extra instructions for stack manipulation and I/O operations, which optimized the programming process. Additionally, it supported serial communication, making it suitable for interfacing with external devices. Its 16-bit address bus retained the 64 KB memory addressing capability of its predecessor.

Both the 8080 and 8085 microprocessors laid the groundwork for more advanced microprocessors in the years that followed. They demonstrated the potential of integrated circuits in computing and influenced the design and architecture of subsequent Intel microprocessors. Their legacy endures in the way they revolutionized computing, making technology accessible to a broader audience, and their influence is still felt in the design and architecture of modern microprocessors today.
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