# 15.1 Addressing modes for ti tms320c55x  (Page 4/4)

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## Cdp indirect : cmem

CDP indirect addressing uses the coefficient data pointer (CDP) to point to data. For accessing data memory/registers, the 16-bit CDP is combined with the 7-bit CDPH to generate a 23-bit address. When concatenated, they are called the XCDP. CDP indirect addressing can also be used to address a specific bit in the accumulators, auxiliary registers, and the temporary registers. Pre- and post-increment and decrement as well as an offset can be used with CDP. CDP can be used as an operand in place of Smem, Lmem, and Cmem.

```MOV dbl(Lmem), Cmem MOV dbl(*AR7), *CDP+ ; Values at XAR7 and XAR7 + 1 are read and stored at ; XCDP and XCDP +/- 1 depending on if XCDP was even or odd. ; CDP is incremented by 2 at the end.```

## Coefficient indirect

Coefficient indirect addressing uses the same address generation process as CDP indirect addressing for data-space accesses. It is useful for instructions that need three memory operands per cycle. It can be used for finite impulse response filters, multiply [accumulate/subtract], and dual multiply [accumulate/subtract].

```MPY Xmem, Cmem, ACx :: MPY Ymem, Cmem, ACy ; Cmem must be in a different memory bank from Xmem/Ymem ; for this to work in a single cycle MPY *AR1+, *CDP+, AC0 :: MPY *AR2+, *CDP+, AC1 ; The value at address XAR1 is multiplied by value at ; address XCDP and stored in AC0. At the same time, ; value at XAR2 is multiplied by value at address XCDP ; and stored in AC1. Then CDP is incremented.```

## Other examples

`AMAR *AR3+ ; increments AR3 by 1`

The `amar` (modify auxiliary register) instruction is unusual in the sense that it takes an `Smem` operand but does nothing with the data pointed to by the `ARx` register. Its purpose is to perform any of the allowed register modifications discussed abovewithout having to do anything else. This is often handy when you are using an `Xmem/Ymem` -type instruction but need to do an `ARx` modification that is only allowed with an `Smem` -type operand.

Circular addressing is useful when implementing circular buffers. Circular addressing needs to be enabled for the specific register that is being used to point to memory. This is done by setting the corresponding `ARnLC` register using `BSET ARnLC` . When circular addressing is not needed, `BCLR ARnLC` on the corresponding ARn will disable circular addressing. The circular addressing length will depend on the `BK03` , `BK47` , and `BKC` register values. If you are using `AR0` through `AR3` for the addressing, then `BK03` will be used. `BKC` is the buffer length for `CDP` . One thing to watch out for is the buffer start address registers (BSA01, BSA23, BSA45, BSA67, BSAC) are added to the auxiliary register or CDP register value whenever circular addressing is used. Be sure to re-initialize the BSA register when implementing multiple filters.

```BSET AR1LC ; sets circular addressing for AR1 BCLR AR2LC ; normal addressing for AR2 MOV #13, BK03 ; set buffer length for AR0 through AR3 MACM *AR1+, *AR2+, AC0 ; AC0 = AC0 + ; (value at memory location AR1 + BSA01) x (value at memory location AR2) ; AR1 is incremented with circular addressing, length 13. ; AR2 is simply incremented by 1```

Bit-reversed addressing is often needed with the fast-fourier transform (FFT). This helps to set up a pointer for the next iteration. Enable bit-reversing on an operand by adding a `B` after the increment value. When a bit-reverse operand is used, the auxiliary register can not be used for circular addressing. If circuluar address is enabled, the corresponding buffer start address value (BSAxx) will be added to ARn, but ARn is not modified to stay within the circular buffer.

```MOV Smem, dst MOV *(AR4 + T0B), T2 ; T2 = value at memory location XAR4 ; AR4 is incremented with T0, using reverse carry propagation.```

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are nano particles real
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
no can't
Lohitha
where we get a research paper on Nano chemistry....?
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
how did you get the value of 2000N.What calculations are needed to arrive at it
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