RealView Compilation Tools Compiler Reference Guide - ARM ...

Compiler-specific Features
Where:
smc_num
Is a 16-bit immediate value used in the SMC instruction.
The value of smc_num is ignored by the ARM processor, but can be
used by the SMC exception handler to determine what service is
being requested.
Restrictions
The SMC instruction is available for selected ARM architecture-based processors, if they
have the Security Extensions. See SMC on page 4-137 in the Assembler Guide for more
information.
The compiler generates an error if you compile source code containing the __smc
keyword for an architecture that does not support the SMC instruction.
Example
__smc(5) void mycall(void); /* declare a name by which SMC #5 can be called */
...
mycall(); /* invoke the function */
See also
• SMC on page 4-137 in the Assembler Guide.
4.1.14 __softfp
The __softfp keyword asserts that a function uses software floating-point linkage.
__softfp is a function qualifier. It affects the type of the function.
Note
This keyword has the #pragma equivalent #pragma __softfp_linkage.
Usage
Calls to the function pass floating-point arguments in integer registers. If the result is a
floating-point value, the value is returned in integer registers. This duplicates the
behavior of compilation targeting software floating-point.
This keyword enables the same library to be used by sources compiled to use hardware
and software floating-point.
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