Vault 7: Projects

This publication series is about specific projects related to the Vault 7 main publication.

Supported Data Types and Variables
2012-2013 Microchip Technology Inc. DS50002071C-page 135
secure
This attribute can be used to define protected variables in Secure Segment (SS) RAM:
int __attribute__((secure)) secure_dat[16];
Variables defined in SS RAM will not be initialized on startup. Therefore all variables in
SS RAM must be initialized using inline code. A diagnostic will be reported if initial
values are specified on a secure variable.
String literals can be assigned to secure variables using inline code, but they require
extra processing by the compiler. For example:
char *msg __attribute__((secure)) = "Hello!\n"; /* not supported */
char *msg2 __attribute__((secure));
void __attribute__((secure)) foo2()
{
*msg2 = "Goodbye..\n"; /* value assigned explicitly */
}
In this case, storage must be allocated for the string literal in a memory space which is
accessible to the enclosing secure function. The compiler will allocate the string in a
psv constant section designated for the secure segment.
sfr (address)
The sfr attribute tells the compiler that the variable is an SFR and may also specify
the run-time address of the variable, using the address parameter.
extern volatile int __attribute__ ((sfr(0x200)))u1mod;
The use of the extern specifier is required in order to not produce an error.
space (space)
Normally, the compiler allocates variables in general data space. The space attribute
can be used to direct the compiler to allocate a variable in specific memory spaces.
Memory spaces are discussed further in Section 10.2 Address Spaces. The
following arguments to the space attribute are accepted:
data
Allocate the variable in general data space. Variables in general data space can
be accessed using ordinary C statements. This is the default allocation.
xmemory - dsPIC30F, dsPIC33EP/F DSCs only
Allocate the variable in X data space. Variables in X data space can be accessed
using ordinary C statements. An example of xmemory space allocation is:
int x[32] __attribute__ ((space(xmemory)));
ymemory - dsPIC30F, dsPIC33EP/F DSCs only
Allocate the variable in Y data space. Variables in Y data space can be accessed
using ordinary C statements. An example of ymemory space allocation is:
int y[32] __attribute__ ((space(ymemory)));
Note: By convention, the sfr attribute is used only in processor header files. To
define a general user variable at a specific address use the address attri-
bute in conjunction with near or far to specify the correct addressing
mode.
DD
DD

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