25.4.4 Near Objects
The __near
qualifier can be used to indicate that variables or functions
are located in ‘near memory’. Exactly what constitutes near memory is dependent on the
target device, but it is typically memory that can be accessed with less complex code.
Expressions involving near-qualified objects generally are faster and result in smaller
code.
Use the native keywords discussed in the Differences section to look up information on the semantics of this qualifier.
Some devices may not have such memory implemented, in which case, use of this qualifier
is ignored. Stack-based (auto
and parameter) variables cannot use the
__near
specifier.
Example
The following shows a variable and function qualified using __near
.
__near int serialNo;
__near int ext_getCond(int selector);
Differences
The 8-bit compilers have used the qualifier near
to indicate this
meaning. Functions could not be qualified as near
.
The 16-bit compilers have used the near
attribute with both variables
and functions.
The 32-bit compilers have used the near
attribute for functions,
only.
Migration to the CCI
For 8-bit compilers, change any occurrence of the near
qualifier to __near
, for example, from:
near char template[20];
to:
__near char template[20];
In 16- and 32-bit compilers, change any occurrence of the
near
attribute to __near
, for example, from:
void bar(void) __attribute__ ((near));
int tblIdx __attribute__ ((near));
to
void __near bar(void);
int __near tblIdx;
Caveats
None.