On 31 October 2017 at 08:49, <[email protected]> wrote: > Thank you Charles. Is it a known issue only for control flow logic? When I > use MOV command to save a negative number (MOV r1, -1), then save r1 into > shared RAM, then into a txt file, I do see -1 is saved into the txt file > correctly.
This always works but has nothing to do with the PRU. You can substract a larger value from an unsigned value, which then gets wrapped around; you can then _interpret_ the bit-pattern as a signed value in two-complement and get the expected negative number. This is what you did in this case. This is just a property of how the two-complement encoding works. -h > > On Tuesday, October 31, 2017 at 9:13:31 AM UTC-4, Charles Steinkuehler > wrote: >> >> On 10/30/2017 4:53 PM, [email protected] wrote: >> > I am trying to use QBLT to compare two numbers and found out when one >> > number is negative, the QBLT logic does not seem make right comparison. >> > In >> > the following code, before QBLT, r3 =1-4 = -3, and r2 = 10, so r3 < r2, >> > then the code should execute MOV r3, -1. However, when I run this macro, >> > r3 >> > is set to 1. >> > Anyone notices this issue? Any idea how to fix it? >> >> This is a known issue, the PRU supports *ONLY* unsigned integers. >> >> Write your code properly for unsigned data types and you will not have >> any problems. >> >> -- >> Charles Steinkuehler >> [email protected] > > -- > 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 [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/859b4ea7-a3a6-430d-a715-b5d24ccc6a09%40googlegroups.com. > > For more options, visit https://groups.google.com/d/optout. -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAEQqtJzcZLifkoKKz2ney2Q%3DBhj8vOaCoLO--QanUeLGuiUGww%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
