yet another 28xx missing intrinsic: RPT NOP

Jason R Sachs

I'd like to be able to call __rpt_nop(k) where k is a compile-time constant (either an enum, or a #define, or a constant value computed by at compile time e.g. 3*2+7), and have it translate to "RPT #k || NOP" in assembly.

Could you please add this to the intrinsic wishlist for the 28xx compiler?

I can't find a workaround; I don't think it's possible to convert a compile-time constant to a string value for use in inline assembly. >:(

So the only other alternative (besides automatically generated code) is to explicitly state asm("RPT #13 || NOP") or whatever in the code at each point of use. We use compile-time computed constants all the time and it's rather inconvenient not to be able to use it here for ultrashort delays.

over 14 years ago

0 Paul Knueven over 14 years ago

TI__Expert 4280 points

You might be able to get by with the following:

#define RPT_NOP0(n) __asm(" RPT #(" #n ") || NOP")
#define RPT_NOP(n) RPT_NOP0(n)

#define N 4
#define N6 (6*N)
#define K (N6+3)

RPT_NOP(5);     /* expands to "RPT #(5) || NOP"           and assembles to "RPT #5 || NOP" */
RPT_NOP(N6);    /* expands to "RPT #((6*N)) || NOP"      and assembles to "RPT #24 || NOP" */
RPT_NOP(K-1);   /* expands to "RPT #(((6*4)+3)-1) || NOP" and assembles to "RPT #26 || NOP" */

0 Jason R Sachs over 14 years ago in reply to Paul Knueven

Expert 1890 points

thanks -- that works if I have constants that are computable by the preprocessor. In my specific application, though, I have compile-time constants that are accessible only by the compiler, not the preprocessor.

0 Jason R Sachs over 14 years ago in reply to Jason R Sachs

Expert 1890 points

Also the "RPT loc16" instruction isn't accessable via inline assembly, since there's no way to pass information between C and inline assembly. (Well, that's 99% true, the only workaround is to use global variables and pass data through fixed addresses.)

0 George Mock over 14 years ago in reply to Jason R Sachs

TI__Guru**** 249680 points

I added SDSCM00041697 to the SDOWP system to request this intrinsic. Feel free to track it with the SDOWP link in my sig.

Thanks and regards,

-George

0 Jason R Sachs over 14 years ago in reply to George Mock

Expert 1890 points

thank you!

Code Composer Studio™︎

Code Composer Studio forum

yet another 28xx missing intrinsic: RPT NOP