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TMS320F280049: TMU cycles detail check

Brian Wang0
Expert 5200 points
Part Number: TMS320F280049

Hi team,

I am looking at the TMU cycles in F280049 datasheet. Here is a quick questions:

In the 1st row, it is noted that a = b*2pi would take 2/3 cycles.

1. Why this instruction would take 2 or 3 cycles but not a fixed number?

2. What data type is PI in this instruction? According to my knowledge,C28 is able to hanlde 32 bit float multiply in a single cycle? Why the instruction including PI would take more?

Thanks!

Regards,

Brian

  • 0
    TI__Mastermind 24670 points

    Brian,

    Its' 2 cycles if the 3rd doesn't conflict. Please refer to the corresponding instruction in the Extended Instruction Sets TRM (SPRUHS1) and it will explain the details.

    It's a 32-bit float. Yes, that's an interesting question - single-precision float multiply is 2p cycles (1 cycle + 2nd if it doesn't conflict with the first). I'll try to find out more details.

    Thanks,

    Sira

  • 0 in reply to Sira Rao80
    TI__Mastermind 24670 points

    Brian, it appears there is a bug. The MPY2PIF32 instruction should also take 2p instructions, like the MPYF32. I'll file a JIRA to have this fixed.