Compaq ECQD2KCTE Laptop User Manual


 
10–2 Alpha Architecture Handbook
10.2 Privileged Digital UNIX PALcode
The privileged PALcode instructions can be called only from kernel mode. They provide an interface
to control the privileged state of the machine.
Table 10–2 describes the privileged Digital UNIX PALcode instructions.
rdunique Read unique
The rdunique instruction returns the process unique value.
urti Return from user mode trap
The urti instruction pops from the user stack the registers a0 through a2, the
global pointer, the new user assembler temporary register, the stack pointer, the
program counter, and the processor status register.
wrunique Write unique
The wrunique instruction sets the process unique register.
Table 10–2 : Privileged Digital UNIX PALcode Instruction Summary
Mnemonic Operation and Description
cflush Cache flush The cflush instruction flushes an entire physical page pointed to by
the specified page frame number (PFN) from any data caches associated with
the current processor. All processors must implement this instruction.
cserve Console service This instruction is specific to each PALcode and console
implementation and is not intended for operating system use.
draina Drain aborts The draina instruction stalls instruction issuing until all prior
instructions are guaranteed to complete without incurring aborts.
halt Halt processor The halt instruction stops normal instruction processing.
Depending on the halt action setting, the processor can either enter console
mode or the restart sequence.
rdmces Read machine check error summary The rdmces instruction returns the MCES
register in v0.
rdps Read processor status The rdps instruction returns the current PS.
rdusp Read user stack pointer The rdusp instruction reads the user stack pointer while
in kernel mode and returns it.
rdval Read system value The rdval instruction reads a 64-bit per-processor value and
returns it.
Table 10–1 : Unprivileged Digital UNIX PALcode Instruction Summary (Continued)
Mnemonic Operation and Description