gcc: MSP430 Built-in Functions

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1 6.59.18 MSP430 Built-in Functions
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1 GCC provides a couple of special builtin functions to aid in the writing
1 of interrupt handlers in C.
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1 '__bic_SR_register_on_exit (int MASK)'
1      This clears the indicated bits in the saved copy of the status
1      register currently residing on the stack.  This only works inside
1      interrupt handlers and the changes to the status register will only
1      take affect once the handler returns.
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1 '__bis_SR_register_on_exit (int MASK)'
1      This sets the indicated bits in the saved copy of the status
1      register currently residing on the stack.  This only works inside
1      interrupt handlers and the changes to the status register will only
1      take affect once the handler returns.
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1 '__delay_cycles (long long CYCLES)'
1      This inserts an instruction sequence that takes exactly CYCLES
1      cycles (between 0 and about 17E9) to complete.  The inserted
1      sequence may use jumps, loops, or no-ops, and does not interfere
1      with any other instructions.  Note that CYCLES must be a
1      compile-time constant integer - that is, you must pass a number,
1      not a variable that may be optimized to a constant later.  The
1      number of cycles delayed by this builtin is exact.
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