MPLAB C Compiler for PIC24 MCUs and dsPIC DSCs ... - Microchip

Using the Compiler on the Command Line
TABLE 3-10: MACHINE-INDEPENDENT OPTIMIZATION OPTIONS
Option Definition
-fkeep-inline-functions Even if all calls to a given function are integrated, and the
function is declared static, output a separate run time
callable version of the function. This switch does not
affect extern inline functions.
-fkeep-static-consts Emit variables declared static const when optimization
isn’t turned on, even if the variables aren’t referenced.
The compiler enables this option by default. If you want to
force the compiler to check if the variable was referenced,
regardless of whether or not optimization is turned on,
use the -fno-keep-static-consts option.
-fno-function-cse Do not put function addresses in registers; make each
instruction that calls a constant function contain the
function’s address explicitly.
This option results in less efficient code, but some
strange hacks that alter the assembler output may be
confused by the optimizations performed when this option
is not used.
-fno-inline Do not pay attention to the inline keyword. Normally
this option is used to keep the compiler from expanding
any functions inline. If optimization is not enabled, no
functions can be expanded inline.
-fomit-frame-pointer Do not keep the Frame Pointer in a register for functions
that don’t need one. This avoids the instructions to save,
set up and restore Frame Pointers; it also makes an extra
register available in many functions.
-foptimize-sibling-calls Optimize sibling and tail recursive calls.
3.5.7 Options for Controlling the Preprocessor
The following options control the compiler preprocessor.
TABLE 3-11: PREPROCESSOR OPTIONS
Option Definition
-Aquestion (answer) Assert the answer answer for question question, in case it is
tested with a preprocessing conditional such as #if
#question(answer). -A- disables the standard assertions
that normally describe the target machine.
For example, the function prototype for main might be declared
as follows:
#if #environ(freestanding)
int main(void);
#else
int main(int argc, char *argv[]);
#endif
A -A command-line option could then be used to select
between the two prototypes. For example, to select the first of
the two, the following command-line option could be used:
-Aenviron(freestanding)
-A -predicate =answer Cancel an assertion with the predicate predicate and answer
answer.
-A predicate =answer Make an assertion with the predicate predicate and answer
answer. This form is preferred to the older form
-A predicate(answer), which is still supported, because it
does not use shell special characters.
© 2008 Microchip Technology Inc. DS51284H-page 51