HPC16003 datasheet(31/36 Pages) NSC

31 / 36 page

Code Efficiency

One of the most important criteria of a single chip microcon-

troller is code efficiency The more efficient the code the

more features that can be put on a chip The memory size

on a chip is fixed so if code is not efficient features may

have to be sacrificed or the programmer may have to buy a

larger more expensive version of the chip

The HPC16083 has been designed to be extremely code-

efficient The HPC16083 looks very good in all the standard

coding benchmarks however it is not realistic to rely only

on benchmarks Many large jobs have been programmed

onto the HPC16083 and the code savings over other popu-

lar microcontrollers has been considerable

Reasons for this saving of code include the following

SINGLE BYTE INSTRUCTIONS

The majority of instructions on the HPC16083 are single-

byte There are two especially code-saving instructions

JP is a 1-byte jump True it can only jump within a range of

plus or minus 32 but many loops and decisions are often

within a small range of program memory Most other micros

need 2-byte instructions for any short jumps

JSRP is a 1-byte call subroutine The user makes a table of

the 16 most frequently called subroutines and these calls

will only take one byte Most other micros require two and

even three bytes to call a subroutine The user does not

have to decide which subroutine addresses to put into the

table the assembler can give this information

EFFICIENT SUBROUTINE CALLS

The 2-byte JSR instructions can call any subroutine within

plus or minus 1k of program memory

MULTIFUNCTION INSTRUCTIONS FOR DATA MOVE-

MENT AND PROGRAM LOOPING

The HPC16083 has single-byte instructions that perform

multiple tasks For example the XS instruction will do the

following

1 Exchange A and memory pointed to by the B register

2 Increment or decrement the B register

3 Compare the B register to the K register

4 Generate a conditional skip if B has passed K

The value of this multipurpose instruction becomes evident

when looping through sequential areas of memory and exit-

ing when the loop is finished

BIT MANIPULATION INSTRUCTIONS

Any bit of memory IO or registers can be set reset or

tested by the single byte bit instructions The bits can be

addressed directly or indirectly Since all registers and IO

are mapped into the memory it is very easy to manipulate

specific bits to do efficient control

DECIMAL ADD AND SUBTRACT

This instruction is needed to interface with the decimal user

world

It can handle both 16-bit words and 8-bit bytes

The 16-bit capability saves code since many variables can

be stored as one piece of data and the programmer does

not have to break his data into two bytes Many applications

store most data in 4-digit variables The HPC16083 supplies

8-bit byte capability for 2-digit variables and literal variables

MULTIPLY AND DIVIDE INSTRUCTIONS

The HPC16083 has 16-bit multiply 16-bit by 16-bit divide

and 32-bit by 16-bit divide instructions This saves both

code and time Multiply and divide can use immediate data

or data from memory The ability to multiply and divide by

immediate data saves code since this function is often

needed for scaling base conversion computing indexes of

arrays etc

Development Support

HPC MICROCONTROLLER DEVELOPMENT SYSTEM

National Semiconductor’s HPC microcontroller develop-

ment is supported through a combination of third party hard-

ware and software coupled with NSC in-house developed

software consisting of compilers assemblers linkers cross

converters and debuggers The code modules can then be

transferred to many EPROM programming systems

CUSTOMER SUPPORT

National Semiconductor’s Customer Response Center

(CRC) provides samples literature prices product informa-

tion The CRC’s engineering staff is prepared to answer

questions regarding specific design and application ques-

tions regarding specific design and application questions

Call any weekday 700 AM to 700 PM central time (US) to

1-800-272-9959 or contact your regional business center

HPC16003 Datasheet(PDF) 31 Page - National Semiconductor (TI)

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