On 2013-01-15, at 14:32, Michał Pleban wrote: >> Last night I wrote a new routine completely from scratch, using 2KiB of tables and I seem to get only marginally faster than what is inside 1571, still needing 40+ cycles in case of four out of five GCR bytes (after equalising). I disassembled also quickly DolphinDOS 2 ROM and I seem to have found some rather big tables inside but didn't extract and analysed the actual routines. Especially that Julian recently wrote he could possibly have a look at it. > > Can you tell how many cycles do you actually need to decode 5 GCR bytes? > Are you decoding bytes that are already loaded into a buffer, or on the > fly when reading? According to my count 186 cycles, although the answer is somewhat more difficult than that: I /would/ need 186 cycles, provided that I would read the incoming bytes off the VIA and be able to decode them on the fly (and the routine is bug-free :-). Since with 40+ cycles on most bytes I can't do it on the fly, I need to read/decode off-the buffer. That would add cycles and put me in the range of 200+ cycles, which is about the same as what 1571 routines do off the buffer. -- SD! Message was sent through the cbm-hackers mailing listReceived on 2013-01-15 15:00:03
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