<< Chapter < Page Chapter >> Page >
The TI TMS320C54x microprocessor provides a number of ways to specify the location of data to be used in calculations. Immediate addressing, direct addressing, and indirect addressing are the three main types. Knowing the basic addressing modes of a microprocessor is important because they map directly into assembly language syntax and because the need to use a particular addressing mode often dictates which instruction one picks for a given task.

Microprocessors provide a number of ways to specify the location of data to be used in calculations. For example, one of thedata values to be used in an add instruction may be encoded as part of that instruction's opcode , the raw machine language produced by the assembler as it parses yourassembly language program. This is known as immediate addressing . Alternatively, perhaps the opcode will instead contain a memory address which holds the data( direct addressing ). More commonly, the instruction will specify that an auxiliary register holds the memory addresswhich in turn holds the data ( indirect addressing ). The processor knows which addressing mode is being used byexamining special bit fields in the instruction opcode.

Knowing the basic addressing modes of your microprocessor is important because they map directly into assembly languagesyntax. Many annoying and sometimes hard-to-find bugs are caused by inadvertently using the wrong addressing mode in aninstruction. Also, in any assembly language, the need to use a particular addressing mode often dictates which instruction onepicks for a given task.

Chapter five, Data Addressing , in the CPU and Peripherals reference contains extended descriptions of most of the addressing modes described below.

Accumulators: src, dst

Whenever the abbreviations src or dst are used in the assembly language syntax description for an instruction, it means that only theaccumulators A and B may be used for that particular operand. These are seen everywhere, but twoclassic examples are ld , which always loads data into an accumulator from somewhere else, and sth/stl , which always store data from an accumulator to somewhere else.

Examples:

ld *AR5,A ; sets A = (contents of memory location pointed to by AR5) sth B,*AR7+ ; sets (contents of memory location pointed to be AR7) = B, ; and then increments AR7 by one

Memory-mapped registers: mmr, mmrx, mmry

Many of the TMS320C54x registers are memory-mapped, meaning that they occupy real addresses at the low end of data memoryspace. The most commonly used of these are the auxiliary registers AR0 through AR7 . Whenever the abbreviation MMR is used in the assembly language syntax description for an instruction, it means thatany memory-mapped register may be used for that particular operand. Only eight instructions use memory-mapped registeraddressing: ldm , mvdm , mvmd , mvmm , popm , pshm , stlm , and stm . With mvmm , since the instruction accepts two memory-mapped register operands, MMRx and MMRy , only AR0 - AR7 and SP may be used.

Questions & Answers

what is mutation
Janga Reply
what is a cell
Sifune Reply
how is urine form
Sifune
what is antagonism?
mahase Reply
classification of plants, gymnosperm features.
Linsy Reply
what is the features of gymnosperm
Linsy
how many types of solid did we have
Samuel Reply
what is an ionic bond
Samuel
What is Atoms
Daprince Reply
what is fallopian tube
Merolyn
what is bladder
Merolyn
what's bulbourethral gland
Eduek Reply
urine is formed in the nephron of the renal medulla in the kidney. It starts from filtration, then selective reabsorption and finally secretion
onuoha Reply
State the evolution relation and relevance between endoplasmic reticulum and cytoskeleton as it relates to cell.
Jeremiah
what is heart
Konadu Reply
how is urine formed in human
Konadu
how is urine formed in human
Rahma
what is the diference between a cavity and a canal
Pelagie Reply
what is the causative agent of malaria
Diamond
malaria is caused by an insect called mosquito.
Naomi
Malaria is cause by female anopheles mosquito
Isaac
Malaria is caused by plasmodium Female anopheles mosquitoe is d carrier
Olalekan
a canal is more needed in a root but a cavity is a bad effect
Commander
what are pathogens
Don Reply
In biology, a pathogen (Greek: πάθος pathos "suffering", "passion" and -γενής -genēs "producer of") in the oldest and broadest sense, is anything that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term pathogen came into use in the 1880s.[1][2
Zainab
A virus
Commander
Definition of respiration
Muhsin Reply
respiration is the process in which we breath in oxygen and breath out carbon dioxide
Achor
how are lungs work
Commander
where does digestion begins
Achiri Reply
in the mouth
EZEKIEL
what are the functions of follicle stimulating harmones?
Rashima Reply
stimulates the follicle to release the mature ovum into the oviduct
Davonte
what are the functions of Endocrine and pituitary gland
Chinaza
endocrine secrete hormone and regulate body process
Achor
while pituitary gland is an example of endocrine system and it's found in the Brain
Achor
what's biology?
Egbodo Reply
Biology is the study of living organisms, divided into many specialized field that cover their morphology, physiology,anatomy, behaviour,origin and distribution.
Lisah
biology is the study of life.
Alfreda
Biology is the study of how living organisms live and survive in a specific environment
Sifune
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Ece 320 - spring 2003. OpenStax CNX. Jan 22, 2004 Download for free at http://cnx.org/content/col10096/1.2
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Ece 320 - spring 2003' conversation and receive update notifications?

Ask