Compaq ECQD2KCTE Laptop User Manual


 
Instruction Descriptions 4–141
4.11.6 Implementation Version
Format:
Operation:
Rc value, which is defined in Appendix D
Exceptions:
Instruction mnemonics:
Description:
A small integer is placed in Rc that specifies the major implementation version of the proces-
sor on which it is executed. This information can be used to make code-scheduling or tuning
decisions, or the information can be used to branch to different pieces of code optimized for
different implementations.
Notes:
The value returned by IMPLVER does not identify the particular processor type.
Rather, it identifies a group of processors that can be treated similarly for performance
characteristics such as scheduling. Ra must be R31 and Rb must be the literal #1 or the
result in Rc is UNPREDICTABLE and it is UNPREDICTABLE whether an exception
is signaled.
Software Note:
Use this instruction to make code-tuning decisions; use AMASK to make instruction-set
decisions.
IMPLVER Rc
!Operate format
None
IMPLVER Implementation Version