Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS MANUAL VOLUME 1 REV 2.3 Manual page 694

PAL_PROC_GET_FEATURES
PAL_PROC_GET_FEATURES – Get Processor Dependent Features
(17)
Provides information about configurable processor features.
Purpose:
Static Registers Only
Calling Conv:
Physical
Mode:
Not dependent
Buffer:
Arguments:
Argument
index
Reserved
feature_set
Reserved
Returns:
Return Value
status
features_avail
feature_status
feature_control
Status:
Status Value
1
0
-2
-3
-8
PAL_PROC_GET_FEATURES and PAL_PROC_SET_FEATURES procedure calls are used
Description:
together to describe current settings of processor features and to allow modification of
some of these processor features.
The feature_set input argument for PAL_PROC_GET_FEATURES describes which
processor feature_set information is being requested.
feature_set zero. The feature_set values are split into two categories: architected and
implementation-specific. The architected feature sets have values from 0-15. The
implementation-specific feature sets are values 16 and above. The architected feature
sets are described in this document. The implementation-specific feature sets are
described in processor-specific documentation.
This procedure will return an invalid argument if an unsupported architectural
feature_set is passed as an input. Implementation-specific feature sets will start at 16
and will expand in an ascending order as new implementation-specific feature sets are
added. The return status is used by the caller to know which implementation-specific
feature sets are currently supported on a particular processor.
For each valid feature_set, this procedure returns which processor features are
implemented in the features_avail return argument, the current feature setting is in
feature_status return argument, and the feature controllability in the feature_control
return argument. Only the processor features which are implemented and controllable
can be changed via PAL_PROC_SET_FEATURES. Features for which features_avail are 0
(unimplemented features) also have features_status and features_control of 0.
In Table 11-112, the class field indicates whether a feature is required to be available
(Req.) or is optional (Opt.). The control field indicates which features are required to be
controllable. Req. indicates that the feature must be controllable, Opt. indicates that
2:446
Description
Index of PAL_PROC_GET_FEATURES within the list of PAL procedures.
0
Feature set information is being requested for.
0
Description
Return status of the PAL_PROC_GET_FEATURES procedure.
64-bit vector of features implemented. See
64-bit vector of current feature settings. See
64-bit vector of features controllable by software.
Description
Call completed without error; The feature_set passed is not supported but a feature_set of a
larger value is supported
Call completed without error
Invalid argument
Call completed with error
feature_set passed is beyond the maximum feature_set supported
Table 11-112.
Table 11-112.
Table 11-112 describes processor
Volume 2, Part 1: Processor Abstraction Layer