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Optimization of the mMIPS

Optimization of the mMIPS. Sander Stuijk. Outline. Video processing I/O operations on the mMIPS Extending the LCC compiler Assignment. Video processing – motion estimation. Video processing – algorithm/architecture codesign. MBS + VIP. MMI+AICP. CAB. MPEG. 1394. Conditional access.

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Optimization of the mMIPS

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  1. Optimization of the mMIPS Sander Stuijk

  2. Outline • Video processing • I/O operations on the mMIPS • Extending the LCC compiler • Assignment

  3. Video processing – motion estimation

  4. Video processing – algorithm/architecture codesign MBS + VIP MMI+AICP CAB MPEG 1394 Conditional access T-PI ASIP GP MSP area(mm2) 1.41 11.4 load(%) 31 37 M-PI eff area(mm2) 0.437 4.2 TriMedia VLIW power(mW) 6.0 124 MIPS bandwidth(MB/s) 135 75 picture-rate up-converter

  5. 400 pixels/line 40 pixels/line 300 lines 30 lines What is an image? • A black and white image is a matrix of luminance values • More pixels means higher image quality

  6. How do you store an image? • An image is a one dimensional pixel array width-1 0 y x width*height-1 Address: [y*width+x]

  7. How many bits do we need per pixel? Experiments: we can distinguish about 200 levels in an image We shall use 8 bit representation of luminance

  8. Video processing • Spatial domain • Image processing on a still image • Examples • Edge detection • Blurring • ... • Temporal domain • Image processing across different points in time • Examples • Motion estimation • Object recognition • ... The assignment deals with still images

  9. 3x3filter Example: filter coefficients are all “1” What does a 3x3 filter do with an image? • A 3x3 filter replaces each pixel (byte) in the file with the weighted sum of the pixel and its eight direct neighbors: • With: • And filter-coefficient Cline,pixel represented by one byte

  10. Blur filter Filter coefficient: +1 +1 +1 +1 +1 +1 +1 +1 +1

  11. C-code for blur filter for(int a=width+1; a<width*height-(width+1); a++){ result=(( 1* (int)buf_i[a-1-width] + 1* (int)buf_i[a-width] + 1* (int)buf_i[a+1-width] + 1* (int)buf_i[a-1] + 1* (int)buf_i[a] + 1* (int)buf_i[a+1] + 1* (int)buf_i[a-1 +width] + 1* (int)buf_i[a+width] + 1* (int)buf_i[a+1+width] +4 )/ 9); if(result<0) buf_o[a]=0; else if(result>255) buf_o[a]=255; else buf_o[a]=result; } clip weighted sum (pixel value) back to one byte

  12. Sharpening filter Filter coefficient: -1 -1 -1 -1 12 -1 -1 -1 -1

  13. Outline • Video processing • I/O operations on the mMIPS • Extending the LCC compiler • Assignment

  14. Input / output input image output image void main(void) { int a, result; char *buf_i = (char*)0x600000, *buf_o = (char*)0x665400; for (a=WIDTH+1; a < WIDTH*HEIGHT-(WIDTH+1);a++) { result=(( -1*(int)buf_i[a-1-WIDTH] + -1*(int)buf_i[a-WIDTH] + -1*(int)buf_i[a+1-WIDTH] + -1*(int)buf_i[a-1] + 12*(int)buf_i[a] + -1*(int)buf_i[a+1] + -1*(int)buf_i[a-1+WIDTH] + -1*(int)buf_i[a+WIDTH] + -1*(int)buf_i[a+1+WIDTH] + 128) / 4); if(result<0) buf_o[a] = 0; else if (result > 255) buf_o[a] = (char)255; else buf_o[a] = result; } }

  15. The input file with image data (name.y format) football.y bicycle.y File: {byte0,byte1,……..byten, bytewidth*height} Pixel left top Pixel right bottom Example: Two pixels above directly above each other: byten and byten+width

  16. Placing an image in the mMIPS memory • lcc -o mips_mem.bin image.c • imgproc.exe -i bicycle.y mips_mem.bin images Start of image in memory (mips_mem.bin)

  17. Extracting an image from the mMIPS memory • imgproc.exe -e mips_ram.dump bicycle.y • ImProc.exe

  18. Outline • Video processing • I/O operations on the mMIPS • Extending the LCC compiler • Assignment

  19. Adding a custom operation to LCC and the mMIPS void main(void) { int a, b, result; char *buf_i = (char*)0x600000, *buf_o = (char*)0x665400; for (a = 1; a < HEIGHT - 1; a++) { for (b = 1; b < WIDTH - 1; b++) { result=(( 5*(int)buf_i[(a - 1) * WIDTH + b - 1] + -3*(int)buf_i[(a - 1) * WIDTH + b ] + 6*(int)buf_i[(a - 1) * WIDTH + b + 1] + -7*(int)buf_i[ a * WIDTH + b - 1] + 11*(int)buf_i[ a * WIDTH + b ] + -7*(int)buf_i[ a * WIDTH + b + 1] + 6*(int)buf_i[(a + 1) * WIDTH + b - 1] + -3*(int)buf_i[(a + 1) * WIDTH + b ] + 5*(int)buf_i[(a + 1) * WIDTH + b + 1] + 128) / 13); /* Absolute value */ if(result<0) buf_o[a * WIDTH + b] = -result; else buf_o[a * WIDTH + b] = result; } } }

  20. Add a custom pattern to the C code #defineabs(a,b) ((a) - ((b) + *(int *) 0x12344321)) void main(void) { int a, b, result; char *buf_i = (char*)0x600000, *buf_o = (char*)0x665400; for (a = 1; a < HEIGHT - 1; a++) { for (b = 1; b < WIDTH - 1; b++) { result=(( 5*(int)buf_i[(a - 1) * WIDTH + b - 1] + -3*(int)buf_i[(a - 1) * WIDTH + b ] + 6*(int)buf_i[(a - 1) * WIDTH + b + 1] + -7*(int)buf_i[ a * WIDTH + b - 1] + 11*(int)buf_i[ a * WIDTH + b ] + -7*(int)buf_i[ a * WIDTH + b + 1] + 6*(int)buf_i[(a + 1) * WIDTH + b - 1] + -3*(int)buf_i[(a + 1) * WIDTH + b ] + 5*(int)buf_i[(a + 1) * WIDTH + b + 1] + 128) / 13); /* Absolute value */ result = abs(result,result); buf_o[a * WIDTH + b] = result; } } }

  21. Adding a custom operation (concept) LCC defines 4 constructs that map to custom operations in LCC: ((a) - ((b) + *(int *) 0x12344321)) ((a) + ((b) + *(int *) 0x12344321)) ((a) - ((b) - *(int *) 0x12344321)) ((a) + ((b) - *(int *) 0x12344321)) More operations (possibly with more operands) can be added. Look at the website for more information.

  22. Custom operations listed in the file lcc/src/minimips.md Add the custom pattern to the LCC compiler opcode = 0 function code = 0x31

  23. Adding a custom operation to LCC and the mMIPS void main(void) { int a, b, result; char *buf_i = (char*)0x600000, *buf_o = (char*)0x665400; for (a = 1; a < HEIGHT - 1; a++) { for (b = 1; b < WIDTH - 1; b++) { result=(( 5*(int)buf_i[(a - 1) * WIDTH + b - 1] + -3*(int)buf_i[(a - 1) * WIDTH + b ] + 6*(int)buf_i[(a - 1) * WIDTH + b + 1] + -7*(int)buf_i[ a * WIDTH + b - 1] + 11*(int)buf_i[ a * WIDTH + b ] + -7*(int)buf_i[ a * WIDTH + b + 1] + 6*(int)buf_i[(a + 1) * WIDTH + b - 1] + -3*(int)buf_i[(a + 1) * WIDTH + b ] + 5*(int)buf_i[(a + 1) * WIDTH + b + 1] + 128) / 13); /* Absolute value */ if(result<0) buf_o[a * WIDTH + b] = -result; else buf_o[a * WIDTH + b] = result; } } }

  24. Add a custom pattern to the C code #defineabs(a,b) ((a) - ((b) + *(int *) 0x12344321)) void main(void) { int a, b, result; char *buf_i = (char*)0x600000, *buf_o = (char*)0x665400; for (a = 1; a < HEIGHT - 1; a++) { for (b = 1; b < WIDTH - 1; b++) { result=(( 5*(int)buf_i[(a - 1) * WIDTH + b - 1] + -3*(int)buf_i[(a - 1) * WIDTH + b ] + 6*(int)buf_i[(a - 1) * WIDTH + b + 1] + -7*(int)buf_i[ a * WIDTH + b - 1] + 11*(int)buf_i[ a * WIDTH + b ] + -7*(int)buf_i[ a * WIDTH + b + 1] + 6*(int)buf_i[(a + 1) * WIDTH + b - 1] + -3*(int)buf_i[(a + 1) * WIDTH + b ] + 5*(int)buf_i[(a + 1) * WIDTH + b + 1] + 128) / 13); /* Absolute value */ result = abs(result,result); buf_o[a * WIDTH + b] = result; } } }

  25. Open een cygwin shell en voer de volgende commando’s uit: lcc image.c –o mips_mem.bin disas mips_mem.bin | less Zoek een assembler instructie met opcode 0 and function code 0x31 Controleer dat clipping gebruikt wordt

  26. Adding a special function to the mMIPS (hardware) aluctrl alu

  27. Outline • Video processing • I/O operations on the mMIPS • Extending the LCC compiler • Assignment

  28. Assignment Optimize the run-time of an image processing algorithm running on the mMIPS without reducing the instruction set supported by the hardware. Constraints • All programs that run on the original mMIPS must also run on your design. • Programs running on your design and the original mMIPS must produce bit-exact output Allowed • Adding special instructions to the mMIPS; • Changing the design of the mMIPS (e.g. forwarding). Not-allowed • Modification of the image processing algorithm that are not needed to use special instructions (e.g. replace multiply with shifts).

  29. Testing and implementing the design Test for functional correctness • Run the original mMIPS with the algorithm to produce a reference output. • Compare the results of your mMIPS to the reference output. • You can use the check-image utility for this purpose. • Make sure that your image is large enough to cover all possible cases. Synthesize your design • You must synthesize your design to determine the maximum clock frequency at which your mMIPS can run. • This determines part of the speed-up.

  30. Use the submit-design utility to submit your mMIPS design You can submit a new design as often as you like, but only your last design will be tested Submitting your design

  31. Important dates • Midterm meeting on March 16th in Pav b1 from 10.45 till 12.30. • Submit the first version of your modified mMIPS on March 18th before noon. • This version must at least contain: • a working forwarding unit, • a working custom clipping instruction. • A separate document (A4, 10pt font, max 2 pages) with a description of all changes made, or planned, or investigated • Provide a short description of the required changes • Provide a short motivation for the change • Explain the expected performance gain • Send document to s.stuijk@tue.nl • Instructions at www.es.ele.tue.nl/education/5JJ55-65/mmips • If you submit a design and document, then you will get feedback on your ideas!

  32. Important dates • Submit the final version of your modified mMIPS on April 1st before noon. • Instructions at www.es.ele.tue.nl/education/5JJ55-65/mmips • This is a hard deadline, no extension is possible! • Individual presentation of your mMIPS on April 4-5th • The presentation is about the changes you made to the mMIPS. • Do not talk about the book, forwarding or clipping.

  33. Every Monday from 15.45 till 17.30 in PT 9.10 Check also www.es.ele.tue.nl/education/5JJ55-65/mmips for more information, hints, etc. Support and information

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