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Compiler-specific Features
See also
• Other builtin functions on page 4-197
• __current_pc on page 4-78
• __return_address on page 4-95
• Legacy inline assembler that accesses sp, lr, or pc on page 7-27 in the Compiler
User Guide.
4.7.7 __disable_fiq
This intrinsic disables FIQ interrupts.
Note
Typically, this intrinsic disables FIQ interrupts by setting the F-bit in the CPSR.
However, for v7-M it sets the fault mask register (FAULTMASK). FIQ interrupts are
not supported in v6-M.
Syntax
int __disable_fiq(void);
void __disable_fiq(void);
Usage
The function prototype to use for this intrinsic depends on the target architecture you
are compiling for. For ARMv7 (--cpu=7), use void __disable_fiq(void);. For all other
architectures, including ARMv7-A, ARMv7-R, and ARMv7-M, you can use
int __disable_fiq(void); or void __disable_fiq(void);.
Return value
int __disable_fiq(void); returns the value the FIQ interrupt mask has in the PSR prior
to the disabling of FIQ interrupts.
Restrictions
The difference in function prototypes between the generic ARMv7 architecture and the
ARMv7 A, R, and M-profiles exists because the way that the previous FIQ state is
returned differs between the M-profile and the A and R-profiles. This means that when
you compile with --cpu=7, the compiler is unable to generate an instruction sequence
that works on all ARMv7 processors, so you must use the void __disable_fiq(void);
function prototype with --cpu=7.
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