specialized video (8-bit) and vector (16-bit) instructions on the blackfin there is always a...

Specialized Video (8-bit) and Vector (16-bit) Instructions on the Blackfin

There is always a “MAKE-UP-YOUR-QUESTION-AND-ANSWER-IT” Question on a Dr. Smith Final.

Must be at an appropriate level for a third year course.

Expand on these ideas for Q9 question and answer on the final

04/18/23Video , Copyright M. Smith, ECE, University of Calgary, Canada

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Problem to solve

Using the video capability on Blackfin Specialized instructions

Examine and explain examples in detail (working program) for Q9 format for final.

Take something we have done in a laboratory and vectorize it for example

Vectorize – take a 32-bit set of data operations and demonstrate the same concept with 8-bit data – but doing 4 operations at the same time.


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Blackfin Evaluation Board

8-bit values


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Getting video information in

DMA activity Values coming in using PPI (Parallel Port Interface)

which shares many of its pins with PF Stored video information in SDRAM BF561 – 2 core Blackfin, handles both video in and

out at the same time Possible Q9 question – one whole chapter in

Hardware book on this area

Video library for Blackfin developed in 2004 by Swiss International Internship students

www.enel.ucalgary.ca/People/Smith/ECE-ADI-Project/CourseInfo/VideoCourseInfoFrame.htm


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Special 8 bit ALUS


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Video image

Blanking information

Frame 1 - luminance + colour information


Frame 2 - luminance + colour information


Have ability to manipulate frame information without touching blanking information


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Frame information

Pixel 1 uses G1 + CB1 + CR1 Pixel 2 uses G2 + CB1 + CR1 Pixel 3 uses G3 + CB3 + CR3 Pixel 4 uses G4 + CB3 + CR3

CB1 G1 CR1 G2 CB3 G3 CR3 G4 CB5 G5 CR5 G6

Image brightness decreasing


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Frame information

R0 = [P0] brings in information on pixel 1 and 2 intensity and colourOne memory access, 2 pixel info

One memory access, 4 pixel intensity information

CB1 G1 CR1 G2 CB3 G3 CR3 G4 CB5 G5 CR5 G6

G1 G2 G3 G4 G5 G6 G7 G8


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BYTEOP16P (Quad 8-bit ADD)Four 8-bit ADDs in a single cycle

8 pixel values stored in R1 and R0 -- 2 registers used at the same time I0 register used to select which 4 pixel values used in operations –

called “byte alignment” I0 = 0; use all bytes in R0 I0 = 1; Lowest byte in R1, top 3 in R0

8 pixel value stored in R3 and R2 I1 used to select the 4 pixels used

If I0=1, I1 = 1; and(R4, R6) = byteop16p(R3:2, R1:0) ; // sum -- 6 registers at the same time

then we got 4 16-bit answers -- “my byte notation”R4.H = R3.B0 + R1.B0; // Bottom byteR4.L = R2.B3 + R0.B3; // Highest byteR6.H = R2.B2 + R0.B2; // Next highest byteR6.L = R2.B1 + R0.B1; // Next highest byte


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BYTEOP1P (Quad 8-bit Average) Four 8-bit ADDs + average in a single cycle

8 pixel values stored in R1 and R0 I0 register used to select which 4 pixel values used in

operations – called “byte alignment” I0 = 0; use all bytes in R0 I0 = 1; Lowest byte in R1, top 3 in R0


If I0=1, I1 = 1; andR4 = byteop1p(R3:2, R1:0) ; // sum and averagethen we got 4 16-bit answersR4.B3 = (R3.B0 + R1.B0) / 2; // Bottom byteR4.B2 = (R2.B3 + R0.B3) / 2; // Highest byteR4.B1 = (R2.B2 + R0.B2) / 2; // Next highest byteR4.B0 = (R2.B1 + R0.B1) / 2; // Next highest byte


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BYTEOP2P (Quad 8-bit Average Half word)

Six 8-bit ADDs + average in a single cycle 8 pixel values stored in R1 and R0

I0 register used to select which 4 pixel values used in operations – called “byte alignment”

I0 = 0; use all bytes in R0 I0 = 1; Lowest byte in R1, top 3 in R0


If I0=1, I1 = 1; andR4 = byteop2p(R3:2, R1:0) ; // sum and averagethen we got 4 16-bit answersR4.B2 = (R3.B0 + R1.B0 + R2.B3 + R0.B3) / 4; // Highest 4 bytesR4.B0 = (R2.B2 + R0.B2 + R2.B1 + R0.B1) / 4;


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BYTEOP16M -- 4 subtracts in 1 cycle (Quad 8-bit SUBTRACT)

8 pixel values stored in R1 and R0 I0 register used to select which 4 pixel values used in operations –

called “byte alignment” I0 = 0; use all bytes in R0 I0 = 1; Lowest byte in R1, top 3 in R0


If I0=1, I1 = 1; and(R4, R6) = byteop16M(R3:2, R1:0) ; // MINUS operation

then we got 4 16-bit answers -- “my byte notation”R4.H = R3.B0 - R1.B0; // Bottom byteR4.L = R2.B3 - R0.B3; // Highest byte --- Video survellianceR6.H = R2.B2 - R0.B2; // Next highest byteR6.L = R2.B1 - R0.B1; // Next highest byte


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SAA -- Quad 4-bit Subtract, Absolute and Accumulate

Take the differences between 2 imagesR0 = [P0++]; -- 4 pixels – image 1 – reading from image 1R1 = [I1++]; -- 4 pixels -- image 2 – reading from image 1 R2 = 0; -- sum of differencesLoop N - 1 times -- Do a zero-overhead loop over all the images

R2 = SAA(R1, R0) || R0 = [P0++] || R1 = [I1++];

R2 = SAA(R1, R0); -- Finish off the operations in the Blackfin pipeline

Now demonstrate adding the 4 bytes together from R2 How to do efficiently – sounds like Q9 question to me

R2 = SAA(R1, R0) || R0 = [P0++] || R1 = [I1++];We have 4 subtracts down, 4 absolute values done and 8 pixel reads AND two pointer updates -- all in a single cycle – parallel instructions denoted by ||


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Worked Examples


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Vector operations

Many of the operations give 16 bit results Example Quad 8-bit Add

(R4, R6) = byteop16P(R3:2, R1:0) Now you want to add the results together

R5 = R4 +|- R6; R4.H + R6.H with R4.L + R6.L R5.L = R5.H + R5.L (NS);


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Vector operations

R0 = R1 +|+ R0; R1.H + R0.H, R1.L + R0.L R0 = R1 +|+ R0 (co); R1.H + R0.L, R1.L + R0.H

co – word order “cross over” Can be +|+, +|-, -|+ or -|-;

R3 = R1 + R0, R4 = R1 – R0; 32 bit add and subtract at same time Must use same source registers

R3 = R1 +|+ R0, R1 -|- R0; 2 16-bit adds and 2 16-bit subtracts at same time

R3 = R1 +|+ R0, R1 -|- R0 (asr); 2 16-bit adds and 2 16-bit subtracts at same time –

and then afterwards do an arithmetic shift right (add and average, subtract and average)


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Vector operations

Normal max instruction (32-bit)R0 = MAX(R1, R2);R0 is largest of R1 and R2Ditto MIN(R1, R2);

Vector maxR0 = MAX(R1, R2) (V)R0.H is largest of R1.H and R2.HR0.L is largest of R0.L and R2.L


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VIT_MAX – Compare and Select

R0 = VIT_MAX(R1, R2);R1 = 0x23000002R2 = 0x70000001R2.H and R1.L are largest

R0 = 0x70000002A0.W = binary 10 indicating R2.H

and R1.L was largest


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Other neat vector operations

Vector ABS R2 = ABS R1 (V);absolute values of R1.H and R1.L

stored in R2 Vector arithmetic shift

R2 = R1 >>> 3 (V) – 2 16-bit shifts Vector multiply and accumulate Vector Negate -- etc


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Worked examples


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Problem to solve

Using the video capability on Blackfin Specialized instruction

Examine and explain examples in detail (working program) for Q9 format for final.

Take something we have done in a laboratory and vectorize it for example


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Information taken from Analog Devices On-line Manuals with permission http://www.analog.com/processors/resources/technicalLibrary/manuals/

Information furnished by Analog Devices is believed to be accurate and reliable. However, Analog Devices assumes no responsibility for its use or for any infringement of any patent other rights of any third party which may result from its use. No license is granted by implication or otherwise under any patent or patent right of Analog Devices. Copyright Analog Devices, Inc. All rights reserved.

specialized video (8-bit) and vector (16-bit) instructions on the blackfin there is always a...

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