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

Using the Compiler on the Command Line
3.5.1 Options Specific to dsPIC DSC Devices
For more information on the memory models, see Section 4.6 “Memory Models”.
TABLE 3-2: dsPIC ® DSC DEVICE-SPECIFIC OPTIONS
Option Definition
-mconst-in-code Put constants in the auto_psv space. The compiler will access these
constants using the PSV window. (This is the default.)
-mconst-in-data Put constants in the data memory space.
-merrata= This option enables specific errata work arounds identified by id. Valid
id[,id]*
values for id change from time to time and may not be required for a
particular variant. An id of list will display the currently supported
errata identifiers along with a brief description of the errata. An id of
all will enable all currently supported errata work arounds.
-mlarge-code Compile using the large code model. No assumptions are made about
the locality of called functions.
When this option is chosen, single functions that are larger than 32k
are not supported and may cause assembly-time errors since all
branches inside of a function are of the short form.
-mlarge-data Compile using the large data model. No assumptions are made about
the location of static and external variables.
-mcpu=
This option selects the target processor ID (and communicates it to the
target
assembler and linker if those tools are invoked). This option affects how
some predefined constants are set; see Section 3.7 “Predefined
Macro Names” for more information. A full list of accepted targets can
be seen in the Readme.htm file that came with the release.
-mpa (1)
Enable the procedure abstraction optimization. There is no limit on the
nesting level.
-mpa=n (1)
-mno-pa (1)
Enable the procedure abstraction optimization up to level n. If n is zero,
the optimization is disabled. If n is 1, first level of abstraction is allowed;
that is, instruction sequences in the source code may be abstracted
into a subroutine. If n is 2, a second level of abstraction is allowed; that
is, instructions that were put into a subroutine in the first level may be
abstracted into a subroutine one level deeper. This pattern continues
for larger values of n.
The net effect is to limit the subroutine call nesting depth to a maximum
of n.
Do not enable the procedure abstraction optimization.
(This is the default.)
Note 1: The procedure abstractor behaves as the inverse of inlining functions. The pass is
designed to extract common code sequences from multiple sites throughout a
translation unit and place them into a common area of code. Although this option
generally does not improve the run-time performance of the generated code, it can
reduce the code size significantly. Programs compiled with -mpa can be harder to
debug; it is not recommended that this option be used while debugging using the
COFF object format.
The procedure abstractor is invoked as a separate phase of compilation, after the
production of an assembly file. This phase does not optimize across translation
units. When the procedure-optimizing phase is enabled, inline assembly code must
be limited to valid machine instructions. Invalid machine instructions or instruction
sequences, or assembler directives (sectioning directives, macros, include files,
etc.) must not be used, or the procedure abstraction phase will fail, inhibiting the
creation of an output file.
© 2008 Microchip Technology Inc. DS51284H-page 35