5 sysenter/sysexit stack pointer msr (sys_sp_msr), 00000175h, Sysenter/sysexit stack pointer msr (sys_sp_msr) – AMD Geode LX [email protected] User Manual
Page 113: 00000000_00000000h, 00000176h
AMD Geode™ LX Processors Data Book
113
CPU Core Register Descriptions
33234H
5.5.2.5
SYSENTER/SYSEXIT Stack Pointer MSR (SYS_SP_MSR)
SYS_SP MSR is used by the SYSENTER instruction (fast system call) as the most privileged stack pointer.
5.5.2.6
SYSENTER/SYSEXIT Instruction Pointer MSR (SYS_IP_MSR)
SYS_IP MSR is used by the SYSENTER instruction (fast system call) as the offset into the most privileged code segment.
MSR Address
00000175h
Type
R/W
Reset Value
00000000_00000000h
SYS_SP_MSR Register Map
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
RSVD
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
ESP
SYS_SP_MSR Bit Descriptions
Bit
Name
Description
63:32
RSVD
Reserved.
31:0
ESP
Enter Stack Pointer. Stack pointer to be used after SYSENTER in most privileged code.
(Default = 0)
MSR Address
00000176h
Type
R/W
Reset Value
00000000_00000000h
SYS_IP_MSR Register Map
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
RSVD
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
EIP
SYS_IP_MSR Bit Descriptions
Bit
Name
Description
63:32
RSVD
Reserved.
31:0
EIP
Enter Instruction Pointer. Offset into the most privileged code segment. (Default = 0)