Programmable processor
A digital signal processor 1 is provided for performing digital image processing operations such as forward texture mapping. A first logic unit 21 receives input sample coordinates xr and xl, and determines a first color weight value “w” and a second color weight value “wN”. A second logic unit 23 weights an input sample color with the color weight value wN, with the resultant weighted sample color being added to accumulated weighted sample colors from one or more previous iterations, thereby producing a new accumulated weighted sample color, ie the rgbaPartOut signal 13 . A third logic unit 25 is configured to weight the input sample color with the first color weight value w, with the resultant weighted sample color being added to the accumulated weighted sample colors rgbaPartIn to produce the output color signal rgbaOut 11 . The logic unit 21 produces the output sample coordinate xOut that relates to the integer coordinate where the color value of output sample rgbaOut 11 is meant for, and also generates a genPix signal that indicates when the output sample is valid. The operation described above continues for all iterations of input sample colors that contribute to a single output sample.
1. A programmable processor for processing one or more input sample values of a digital signal to produce an output signal, the processor comprising:
a first logic unit adapted to generate first and second weight values;
a second logic unit adapted to receive an input sample value and the second weight value, and to weight the input sample value with the second weight value to produce a weighted sample value, and further adapted to add the weighted sample value to one or more previously generated weighted sample values to generate an accumulated weighted sample value;
a third logic unit adapted to receive the input sample value and the first weight value, and to generate an output sample based on the input sample value, the first weight value and the accumulated weighted sample value output from the second logic unit.
2. A processor as claimed in claim 1 , wherein the first logic unit comprises:
means for receiving a first coordinate signal and a second coordinate signal relating to current and previous sample values, respectively; and
means for generating the first and second weight values based on the first and second coordinate signals.
3. A processor as claimed in claim 2 , wherein the first logic unit further comprises means for increasing the values of the first coordinate signal and the second coordinate signal (xl) by a predetermined value prior to generating the first and second weight values.
4. A processor as claimed in claim 2 , wherein the first logic unit further comprises means for producing an output coordinate signal for the output sample.
5. A processor as claimed in claim 4 , whereby the means for producing the output coordinate signal is adapted to derive the output coordinate signal from an integer part of the second coordinate signal.
6. A processor as claimed in claim 1 , wherein the first logic unit further comprises means for generating a status signal for indicating when the output sample and output coordinate signal are valid.
7. A processor as claimed in claim 1 , wherein the first logic unit further comprises means for preventing decreasing coordinates.
8. A processor as claimed in claim 1 , wherein the first logic unit further comprises means for preventing magnification.
9. A processor as claimed in claim 1 , wherein the second logic unit comprises:
means for receiving the input sample value that contributes to the output sample value;
means for weighting the input sample value with the second weight value to produce a weighted sample value;
means for adding the weighted sample value to an accumulated weighted sample value from a previous iteration, the result forming the accumulated weighted sample value.
10. A processor as claimed in claim 1 , wherein the third logic unit comprises:
means for receiving the input sample value that contributes to the output sample value;
means for weighting the input sample value with the first weight value (w) to produce a weighted sample value;
means for adding the weighted sample value to an accumulated weighted sample value from a previous iteration, the result forming the output sample.
11. A processor as claimed in claim 1 , wherein the accumulated weighted sample value is stored in a register file of a corresponding processor.
12. A processor as claimed in claim 1 , wherein an input sample value relates to an input sample color of an image signal, and wherein a weight value relates to a color weight value.
13. A processor as claimed in claim 12 , wherein the processor is configured to perform a two dimensional image signal resampling operation.
14. A processor as claimed in claim 1 , wherein one or more of the logic units are combined into a single operational unit.
15. A processor as claimed in claim 14 , wherein a register storing the accumulated weighted sample value forms part of the single operational unit.
16. A processor as claimed in claim 1 , wherein one or more of the logic units form several operational units.
17. A method of performing a digital signal processing operation in which one or more input sample values of a digital signal are processed to produce an output signal, the method comprising the steps of:
generating by a processor first and second weight values;
weighting by a processor an input sample value with the second weight value to produce a weighted sample value, and adding the weighted sample value to one or more previously generated weighted sample values to generate an accumulated weighted sample value; and
generating by a processor an output sample based on the input sample value, the first weight value (w) and the accumulated weighted sample value.
18. A method as claimed in claim 17 , wherein the step of generating the first and second weight values comprises the steps of:
receiving by a processor a first coordinate signal and a second coordinate signal relating to current and previous samples, respectively; and
generating by a processor the first and second weight values based on the first and second coordinate signals.
19. A method as claimed in claim 18 , wherein the step of generating the first and second weight values further comprises the step of increasing by a processor the values of the first coordinate signal (xr) and the second coordinate signal by a predetermined value prior to generating the first and second weight values.
20. A method as claimed in claim 18 , further comprising the step of producing by a processor an output coordinate signal for the output sample.
21. A method as claimed in claim 20 , wherein the step of producing the output coordinate signal involves deriving by a processor the output coordinate signal from an integer part of the second coordinate signal.
22. A method as claimed in claim 17 , further comprising the step of generating by a processor a status signal for indicating when the output sample and output coordinate signal are valid.
23. A method as claimed in claim 17 , further comprising the step of preventing decreasing coordinates by a processor.
24. A method as claimed in claim 17 , further comprising the step of preventing magnification by a processor.
25. A method as claimed in claim 17 , wherein the step of generating an accumulated weight sample value comprises the steps of:
receiving by a processor the input sample value that contributes to the output sample;
weighting by a processor the input sample value with the second weight value to produce a weighted sample value;
adding by a processor the weighted sample value to an accumulated weighted sample value from a previous iteration, the result forming the accumulated weighted sample value.
26. A method as claimed in claim 17 , wherein the step of generating the output sample comprises the steps of:
receiving by a processor the input sample value that contributes to the output sample;
weighting by a processor the input sample value with the first weight value (w) to produce a weighted sample value;
adding by a processor the weighted sample value to an accumulated weighted sample value from a previous iteration, the result forming the output sample.
27. A method as claimed in claim 17 , further comprising the step of storing by a processor the accumulated weighted sample value in a register file of a corresponding processor.
28. A method as claimed in 17 , wherein an input sample value relates to an input sample color of an image signal, and wherein a weight value relates to a color weight value.
29. A method as claimed in claim 28 , wherein the method steps form a two dimensional image signal resampling operation by a processor.
30. A method as claimed in claim 17 , wherein one or more of the steps are combined into a single operation by a processor.
31. A method as claimed in claim 17 , wherein one or more of the steps are combined into several operations by a processor.