INSTRUCTION SET REFERENCE

Table A-20. Summary of Compare Instructions

Compare

CMP <dest>,<src>

dest opnd – src opnd

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Mnemonic

<dest>,<src>

 

Notes

 

Binary Mode

Source Mode

 

 

Bytes

 

States

Bytes

 

States

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rmd,Rms

Reg with reg

 

 

3

 

2

2

 

1

 

 

 

 

 

 

 

 

 

 

 

WRjd,WRjs

Word reg with word reg

 

3

 

3

2

 

2

 

 

 

 

 

 

 

 

 

 

 

DRkd,DRks

Dword reg with dword reg

 

3

 

5

2

 

4

 

 

 

 

 

 

 

 

 

 

 

Rm,#data

Reg with immediate data

 

4

 

3

3

 

2

 

 

 

 

 

 

 

 

 

 

 

WRj,#data16

Word reg with immediate 16-bit data

 

5

 

4

4

 

3

 

 

 

 

 

 

 

 

 

 

 

DRk,#0data16

Dword reg with zero-extended 16-bit

 

5

 

6

4

 

5

 

 

immediate data

 

 

 

 

 

 

 

 

CMP

 

 

 

 

 

 

 

 

 

DRk,#1data16

Dword reg with one-extended 16-bit

 

5

 

6

4

 

5

 

 

immediate data

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rm,dir8

Dir addr from byte reg

 

4

 

3†

3

 

2†

 

WRj,dir8

Dir addr from word reg

 

4

 

4

3

 

3

 

 

 

 

 

 

 

 

 

 

 

Rm,dir16

Dir addr (64K) from byte reg

 

5

 

3

4

 

2

 

 

 

 

 

 

 

 

 

 

 

WRj,dir16

Dir addr (64K) from word reg

 

5

 

4

4

 

3

 

 

 

 

 

 

 

 

 

 

 

Rm,@WRj

Indir addr (64K) from byte reg

 

4

 

3

3

 

2

 

 

 

 

 

 

 

 

 

 

 

Rm,@DRk

Indir addr (16M) from byte reg

 

4

 

4

3

 

3

 

 

 

 

 

 

 

 

 

 

 

†If this instruction addresses an I/O port (Px, x = 3:0), add 1 to the number of states.

A-15

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Intel 8XC251SQ Table A-20. Summary of Compare Instructions, Compare CMP dest,src, Dest,src Binary Mode Source Mode, Cmp
Page 266 Page 268

Embedded Microcontroller, 8XC251SP, 8XC251SA, 8XC251SQ, 8XC251SB specifications

The Intel 8XC251 series of embedded microcontrollers is a family of versatile and powerful devices, designed to meet the demands of a wide range of applications. With models such as the 8XC251SB, 8XC251SQ, 8XC251SA, and 8XC251SP, this series offers unique features while maintaining a high level of performance and reliability.

At the heart of the 8XC251 microcontrollers is the 8051 architecture, which provides a 16-bit processor capable of executing complex instructions efficiently. This architecture not only allows for a rich instruction set but also facilitates programming in assembly language and higher-level languages like C, which are essential for developing sophisticated embedded systems.

One of the significant features of the 8XC251 family is its integrated peripherals, including timer/counters, serial communication interfaces, and interrupt systems. These peripherals enable developers to implement timing functions, data communication, and real-time processing, all of which are crucial in modern embedded applications. The 8XC251SB and 8XC251SQ models, for instance, come equipped with multiple I/O ports that allow for interfacing with other devices and systems, enhancing their functionality in various environments.

The memory architecture of the 8XC251 devices is noteworthy, featuring on-chip ROM, RAM, and EEPROM. The on-chip memory allows for fast access times, which is essential for executing programs efficiently. Moreover, the EEPROM serves as non-volatile memory, enabling the storage of configuration settings and important data that must be retained even when power is lost.

In terms of operating voltage, the 8XC251 devices are designed to operate in a wide range, typically between 4.0V and 6.0V. This flexibility makes them suitable for battery-powered applications, where energy efficiency is critical. The power management features, including reduced power modes, further enhance their suitability for portable devices.

Lastly, the 8XC251 series is supported by a wide range of development tools and resources, allowing engineers and developers to streamline the development process. This support, combined with the microcontrollers' robust features, makes the Intel 8XC251 family a reliable choice for various embedded applications, such as industrial automation, automotive systems, and consumer electronics.

Overall, the Intel 8XC251SB, 8XC251SQ, 8XC251SA, and 8XC251SP deliver high performance, versatility, and ease of use, making them a preferred choice for embedded system designers looking to develop efficient and effective solutions.
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