Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS MANUAL VOLUME 1 REV 2.3 Manual page 647

PAL_HALT – Halt Processor (28)
Causes the processor to enter the HALT state, or one of the implementation-dependent
Purpose:
low-power states.
Static Registers Only
Calling Conv:
Physical
Mode:
Not dependent
Buffer:
Arguments:
Argument
index
halt_state
io_detail_ptr
Reserved
Returns:
Return Value
status
load_return
Reserved
Reserved
Status:
Status Value
0
-1
-2
-3
This call places the processor in a low power state designated by halt_state. This
Description:
procedure can optionally let the platform know it is about to enter the low power state
via an I/O transaction.
halt_state is an unsigned 64-bit integer denoting the low power state requested. The
value passed must be a valid halt state in the range from 1 to 7, for which information
is returned by PAL_HALT_INFO. All other values are reserved.
The processor informs the platform that it has entered the requested low-power state in
an implementation-specific manner.
The layout of the information pointed to by the io_detail_ptr is shown
Table 11-82. I/O Detail Pointer Description
Offset
0x0 I/O size and type information
0x8 Address for I/O
0x10 Data value to store
• I/O size and type information has the format shown in
Figure 11-13. I/O Size and Type Information Layout
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32
Volume 2, Part 1: Processor Abstraction Layer
Description
Index of PAL_HALT within the list of PAL procedures.
Unsigned 64-bit integer denoting low power state requested.
8-byte aligned physical address pointer to information on the type of I/O (load/store)
requested.
0
Description
Return status of the PAL_HALT procedure.
Value returned if a load instruction is requested in the io_detail_ptr
0
0
Description
Call completed without error
Unimplemented procedure
Invalid argument
Call completed with error
Description
reserved
Figure
8
I/O size
reserved
PAL_HALT
Table 11-82.
11-13.
7 6 5 4 3 2 1 0
I/O type
2:399