On Thu, 10 May 2012, davee.roberts@fsmail.net wrote: > Having just coded up the VHDL for the CRC computations for both ethernet and HDLC then I would suspect that the internals of the 6702 are a state machine that depends upon the value written and the current value. The XOR operator and logical shifts (left or right) or rotates (left or right) will also come into the equation. So keep an eye out for these operators in the numbers that get spat out. As Segher has already hinted - convert the numbers to hex, octal or binary rather than decimal and you may see the pattern easier. > If we can get a printout of the exact number sequence on this thread (and the values you poked in to obtain them) this would allow some degree of 'parallel processing' to the problem. Multiple hackers working in different time zones all with different ideas working on a single problem - either a recipe for disaster or success! > Cheers, > Dave I haven't been saving the sequence, only which numbers were generated. A sequence could be hundreds or even thousands of numbers. This would require writing them to a disk file, and using disk interrupts could possibly complicate the process. The procedure to produce the numbers is to write an even number and then an odd number. This causes the output to change. As long as you keep writing the same two numbers, the pattern stays the same. If you write different numbers the pattern changes. I have been staying with writing 0 and 1, mostly. The run that is going now produces 48 numbers, all with bits 4 and 6 low. The numbers are: 0, 1, 3, 4, 5, 7, 17, 18, 19, 21, 22, 23 This repeats adding multiples of 64. Although you could fit a formula to any given pattern, what we are looking for is a formula that generates a series of formulas with very little input. wlevak@sdf.lonestar.org SDF Public Access UNIX System - http://sdf.lonestar.org Message was sent through the cbm-hackers mailing listReceived on 2012-05-11 06:00:14
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