Hi , We are trying to use the MIPS-DSP-ASE instructions to extract bits from a bit-stream. The version is MIPS-32 rev 1. (Little Endian) (Linux 2.6.30.9) The problem is that, the extp and its variants extract the bits from left-most i.e. MSB. So each time we have to load to the accumulator, we have to reverse the stream and then load, and extract and then reverse. This in-turn is reducing the perfomance rather than increasing it. For instance, Stream -> 111011011 extract 3-bits in C code => 011 (x = (unsigned) stream& ((1<<3 )-1) ) Load this stream to accumulator and extract 3 bits => 111 ==== Now reverse the stream and load to accumulator => 110110111 extract 3 bits from accumulator => 110 Now reverse the extracted bits =>011 So we have to reverse the stream before loading to the accumulator and reverse it again after extracting from accumulator which reduces the performance drastically. we guess the MIPS engineers would definitely have thought about it but we are unable to figure out a way to use these instructions without reversing the bit-streams. Please can you let us know a way to use these instructions without reversing. -- Thank you, Warm Regards, Asutosh Das # (91) 9818 4494 69
