AMD-K6 AMD [Advanced Micro Devices], AMD-K6 Datasheet - Page 300

• Manufacturer Part Number: AMD-K6
• Description: AMD-K6 Processor
• Manufacturer: AMD [Advanced Micro Devices]

AMD-K6
Figure 102. Extended Feature Enable Register (EFER)
282
63
®
Processor Data Sheet
Reserved
Symbol
SCE
Table 59. Model-Specific Registers (MSRs)
For mo re info rma tio n abo ut the RD MSR and WRMSR
instructions, see the AMD K86™ Family BIOS and Software Tools
Development Guide, order# 21062.
Extended Feature Enable Register (EFER). T h e E x t e n d e d Fe a t u re
Enable Register (EFER) contains the control bits that enable
the extended features of the AMD-K6. Figure 102 shows the
format of the EFER register, and Table 60 defines the function
of each bit in the EFER register.
Table 60. Extended Feature Enable Register (EFER) Definition
SYSCALL/SYSRET Target Address Register (STAR).
The SYSCALL/SYSRET Target Address Register (STAR)
contains the target EIP address used by the SYSCALL
instruction and the 16-bit code and stack segment selector
bases used by the SYSCALL and SYSRET instructions. Figure
103 shows the format of the STAR register, and Table 61 defines
the function of each bit of the STAR register. For more
information, see the SYSCALL and SYSRET Instruction
Specification Application Note, order# 21086.
Extended Feature Enable Register (EFER)
SYSCALL/SYSRET Target Address Register (STAR) C000_0081h
63–1
Bit
0
System Call/Return Extension
Description
Reserved
System Call/Return Extension (SCE)
Model-Specific Register
Preliminary Information
Software Environment
Description
Bit
0
Value of ECX
R/W
R/W
C000_0080h
R
20695H/0—March 1998
1
Chapter 24
0
C
S
E