You could also use the code snippet in this article to calculate clock cycles for individual instructions:
http://theembeddedkitchen.net/beaglelogic-building-a-logic-analyzer-with-the-prus-part-1/449 On Tuesday, May 26, 2015 at 7:09:38 PM UTC+5:30, marcelo...@gmail.com wrote: > > Sorry, just saw that you actually mentioned that the shared memory has the > same performance as the DRAM. > Also, I found this: > http://processors.wiki.ti.com/index.php/Programmable_Realtime_Unit#Load_.2F_Store_Instructions > where it is said that LBBO should take (1+word count) cycles. If that's > right, an LBBO instruction up to 4 bytes should take 2 cycles for VBUS and > 3 cycles for VBUSP. For now I need to study more to understand which one is > the case, but VBUSP matches with your findings. > > Em sexta-feira, 3 de janeiro de 2014 23:05:30 UTC-2, Lenny escreveu: >> >> Hello, >> >> I am using a Beaglebone Black. When i measured the number of PRU clock >> cycles needed for the execution of various assembler instructions, I found >> surprisingly large values for memory access. Here follows a list, in which >> one cycle corresponds to a delay of 5ns as expected: >> >> Most operations, such as ADD,SUB,QBxx,MOV,JMP etc.: 1 cycle >> >> LBBO 1,2,4 Bytes from PRU DRAM: 3 cycles >> LBBO 8 Bytes from PRU DRAM: 4 cycles >> LBBO 12 Bytes from PRU DRAM: 5 cycles >> LBBO 16 Bytes from PRU DRAM: 6 cycles >> >> LBCO 4 Bytes from DDR: 43 cycles >> LBCO 8 Bytes from DDR: 44 cycles >> LBCO 12 Bytes from DDR: 45 cycles >> LBCO 16 Bytes from DDR: 46 cycles >> >> With PRU DRAM, i mean any addresses between 0x00000000 and 0x00004000 and >> the shared PRU RAM (12 kB starting from 0x00010000). Any other address i >> tried had the delay stated for "DDR". >> >> Can anybody confirm the long DDR (and other delays if possible) readout >> times that I have measured? Does anybody have an explanation for these >> large delays? >> >> Thanks in advance! Lenny >> > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
