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interrupts intrinsics using ARM CC 4.5.2 not recognized

bob frankel
Expert 2470 points

as documented in section 6.7.2 of the TI ARM compiler manual, i'm using the intrinsics _disable_interrupts(), etc within my source code....  when i compile, however, the compiler issues a warning about an implictly-defined functions -- suggesting the intrinsics are somehow not being recognized....

i am compiling my sources for cortex-m3 using the TI ABI  (-mv7M3 --abi=ti_arm9_abi); i had similar problems when using ELF....

what i am missing here???  do i need to include some header???  or are these intrinsics not support on cortext-m3???  or is there some other way (from C) to disable/enable/restore interrupts???

  • 0
    TI__Guru**** 253280 points

    Those intrinsics are not supported when building for Thumb or Thumb2.  Note Thumb2 is the only mode supported on Cortex-M3.  Your best option is to call assembly routines for disabling and enabling interrupts.  I know folks also do it with with asm() statements, but those tend to cause as many problems as they solve.  The documentation should mention this detail.

    Thanks and regards,

    -George

     

  • 0 in reply to George Mock
    Expert 2470 points

    i'm interested in minimizing the overhead of calling an asm function, which itself then executes 1-2 instructions....  the older _{disable,enable,restore}_interrupts() intrinsics did not incur such overhead...

    is there a (clean) way to achieve this with asm statements???  gcc handles this nicely by effectively allowing asm statements to reference registers holding C variables in the surrounding context; auto-inlining then works as expected.

  • 0 in reply to bob frankel
    TI__Guru**** 253280 points

    I encourage folks to avoid asm statements whenever possible.  I also understand wanting to avoid the overhead of a function call. Thus, I concede that asm statements could be a good option for this case.  Just be sure those statements only access the interrupt enable bit (or bits?), and not any C variables, registers the compiler uses, or other elements of the C runtime environment.

    The TI compiler does not support gcc-style asm statements.

    Thanks and regards,

    -George