SW006012 Microchip Technology, SW006012 Datasheet - Page 18

• Manufacturer Part Number: SW006012
• Description: C COMPILER FOR DSPIC30F FAMILY
• Manufacturer: Microchip Technology
• Type: MPLAB® C30 Compilerr
• Series: PIC24 & DsPICr

Specifications of SW006012

• Supported Families: PIC24, DsPIC30F And DsPIC33F
• Core Architecture: PIC, DsPIC
• Kit Contents: Software And Docs
• Mcu Supported Families: PIC24 MCUs And DsPIC DSCs
• Tool Type: Compiler
• Processor Series: PIC24, dsPIC
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: dsPIC30F
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

MPLAB
DS51284F-page 12
®
C30 User’s Guide
2.3.1
The MPLAB C30 keyword __attribute__ allows you to specify special attributes of
variables or structure fields. This keyword is followed by an attribute specification inside
double parentheses. The following attributes are currently supported for variables:
• address (addr)
• aligned (alignment)
• boot
• deprecated
• far
• mode (mode)
• near
• noload
• packed
• persistent
• reverse (alignment)
• section ("section-name")
• secure
• sfr (address)
• space (space)
• transparent_union
• unordered
• unused
• weak
You may also specify attributes with __ (double underscore) preceding and following
each keyword (e.g., __aligned__ instead of aligned). This allows you to use them
in header files without being concerned about a possible macro of the same name.
To specify multiple attributes, separate them by commas within the double
parentheses, for example:
address (addr)
The address attribute specifies an absolute address for the variable. This attribute
can be used in conjunction with a section attribute. This can be used to start a group
of variables at a specific address:
int foo __attribute__((section("mysection"),address(0x900)));
int bar __attribute__((section("mysection")));
int baz __attribute__((section("mysection")));
A variable with the address attribute cannot be placed into the auto_psv space (see
the space() attribute or the -mconst-in-code option); attempts to do so will cause
a warning and the compiler will place the variable into the PSV space. If the variable is
to be placed into a PSV section, the address should be a program memory address.
int var
__
Note:
attribute
__
Specifying Attributes of Variables
It is important to use variable attributes consistently throughout a project.
For example, if a variable is defined in file A with the far attribute, and
declared extern in file B without far, then a link error may result.
attribute
__
((aligned (16), packed)).
__
((address(0x800)));
© 2007 Microchip Technology Inc.