Method and apparatus for performing a pixel averaging instruction
AssigneeIntel Corporation
InventorsYuyun Liao, Nigel C. Paver, James E. Quinlan
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Abstract
In an embodiment, a functional unit including a compressor section and a 36-bit SIMD adder is used to perform a SIMD four-pixel averaging instruction. The functional unit generates four four-pixel averages. Four pixel values and a rounding value are compressed into a sum and a carry vector. The tow least significant bits of the sum vector and the LSB of the carry vector are dropped before being input to the 36-bit SIMD adder. The two resultant 8-bit vectors are added by the 36-bit adder to directly generate the average pixel value result.
Claims23
A method comprising:
- compressing a plurality of pixel values and a rounding vector into a first sum vector and a first carry vector;
- discarding the least significant bit of the first carry vector;
- discarding the two least significant bits of the first sum vector;
- and
- adding the first sum vector and the first carry vector to generate a pixel average value.
The method of claim 37 wherein the pixel values comprise 8-bit values.
Apparatus comprising:
- a compressor stage including a plurality of compressors, each compressor operative to compress a plurality of operands and a rounding vector into a first sum vector and a first carry vector and to discard the two least significant bits (LSBs) of said first sum vector and the LSB of the first carry vector;
- and
- a Single-Instruction/Multiple-Data (SIMD) adder operative to add the first sum vector and the first carry vector to generate an average pixel value.
An article comprising a machine-readable medium include machine readable instructions, the instructions operative to cause a machine to:
- compress a plurality of pixel values and a rounding vector into a first sum vector and a first carry vector;
- discard the least significant bit of the first carry vector;
- discard the two least significant bits of the first sum vector;
- and
- add the first sum vector and the first carry vector to generate a pixel average value.
Dependencies are inferred from the claim text.