Compaq ECQD2KCTE Laptop User Manual


 
11–2 Alpha Architecture Handbook
11.2 Privileged Windows NT Alpha PALcode
The privileged PALcode instuctions provide support for system operations and may be called from
only kernel mode.
imb Instruction memory barrier
The imb instruction guarantees that all subsequent instruction stream fetches
are coherent with respect to main memory. Imb must be issued before execut-
ing code in memory that has been modified (either by stores from the processor
or DMA from an I/O processor). User-mode code that modifies the I-stream
must call the appropriate Windows NT API to ensure I-cache coherency.
kbpt Kernel breakpoint trap
The kbpt instruction raises a breakpoint general exception to the kernel, setting
a KERNEL_BREAKPOINT breakpoint type.
rdteb Read thread environment block pointer
The rdteb instruction returns the contents of the TEB internal processor register
for the currently executing thread (the base address of the thread environment
block).
Table 11–2 : Privileged Windows NT Alpha PALcode Instruction Summary
Mnemonic Operation and description
csir Clear software interrupt request
The csir instruction clears the specified bit in the SIRR internal processor regis-
ter.
dalnfix Disable alignment fixups
The dalnfix instruction disables alignment fixups in PALcode and generates
alignment fault exceptions whenever an alignment fault occurs. After dalnfix is
executed on a processor, all alignment faults on that processor are not fixed-up
by PALcode and alignment fault exceptions are dispatched to the kernel until
the ealnfix instruction is executed on that processor.
di Disable all interrupts
The di instruction disables all interrupts by clearing the interrupt enable (IE) bit
in the PSR internal processor register. The IRQL field is unaffected. Interrupts
may be re-enabled via the ei instruction.
Table 11–1 : Unprivileged Windows NT Alpha PALcode Instruction Summary
Mnemonic Operation and description