These function attributes are supported for ARM targets:
interrupt
You can specify the kind of interrupt to be handled by adding an optional parameter to the interrupt attribute like this:
void f () __attribute__ ((interrupt ("IRQ")));
Permissible values for this parameter are: IRQ
, FIQ
,
SWI
, ABORT
and UNDEF
.
On ARMv7-M the interrupt type is ignored, and the attribute means the function
may be called with a word-aligned stack pointer.
isr
interrupt
attribute above.
long_call
short_call
#pragma long_calls
settings. For ARM, the
long_call
attribute indicates that the function might be far
away from the call site and require a different (more expensive)
calling sequence. The short_call
attribute always places
the offset to the function from the call site into the ‘BL’
instruction directly.
naked
asm
statements can safely be included in naked functions
(see Basic Asm). While using extended asm
or a mixture of
basic asm
and C code may appear to work, they cannot be
depended upon to work reliably and are not supported.
pcs
pcs
attribute can be used to control the calling convention
used for a function on ARM. The attribute takes an argument that specifies
the calling convention to use.
When compiling using the AAPCS ABI (or a variant of it) then valid
values for the argument are "aapcs"
and "aapcs-vfp"
. In
order to use a variant other than "aapcs"
then the compiler must
be permitted to use the appropriate co-processor registers (i.e., the
VFP registers must be available in order to use "aapcs-vfp"
).
For example,
/* Argument passed in r0, and result returned in r0+r1. */ double f2d (float) __attribute__((pcs("aapcs")));
Variadic functions always use the "aapcs"
calling convention and
the compiler rejects attempts to specify an alternative.
target (
options)
On ARM, the following options are allowed:
Functions from different modes can be inlined in the caller's mode.