These function attributes are supported for ARM targets:
Use this attribute to indicate that the specified function is an interrupt handler. The compiler generates function entry and exit sequences suitable for use in an interrupt handler when this attribute is present.
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:
On ARMv7-M the interrupt type is ignored, and the attribute means the function may be called with a word-aligned stack pointer.
Use this attribute on ARM to write Interrupt Service Routines. This is an
alias to the
interrupt attribute above.
These attributes specify how a particular function is called.
These attributes override the
-mlong-calls (see ARM Options)
command-line switch and
#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’
This attribute allows the compiler to construct the
requisite function declaration, while allowing the body of the
function to be assembly code. The specified function will not have
prologue/epilogue sequences generated by the compiler. Only basic
asm statements can safely be included in naked functions
(see Basic Asm). While using extended
asm or a mixture of
asm and C code may appear to work, they cannot be
depended upon to work reliably and are not supported.
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
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
/* 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.
As discussed in Common Function Attributes, this attribute allows specification of target-specific compilation options.
On ARM, the following options are allowed:
Force code generation in the Thumb (T16/T32) ISA, depending on the architecture level.
Force code generation in the ARM (A32) ISA.
Functions from different modes can be inlined in the caller’s mode.
Specifies the fpu for which to tune the performance of this function. The behavior and permissible arguments are the same as for the -mfpu= command-line option.