AMD-K6 Datasheet, PDF (299/346 Pages) Advanced Micro Devices – AMD-K6 Processor

20695H/0—March 1998
Preliminary Information
AMD-K6^® Processor Data Sheet
24 Software Environment
This chapter briefly describes the AMD-K6 Model-Specific
Registers (MSRs) and x86 instructions supported by the
AMD-K6 processor Model 7 that are not supported by the
AMD-K6 processor Model 6.
For an overview of the AMD-K6 processor’s x86 software
environment and a description of the remaining data types,
registers, operating modes, interrupts, and instructions
s u p p o r t e d by t h e A M D -K 6 a rch i t e c t u re a n d d e s i g n
implementation, see Chapter 3, “Software Environment” on
page 21.
24.1
Registers
The AMD-K6 processor contains all the registers defined by the
x86 architecture, including general-purpose, segment,
floating-point, MMX, EFLAGS, control, task, debug, test, and
descriptor/memory-management registers.
This section provides information on the Model-Specific
Registers (MSRs) supported by the AMD-K6 processor Model 7
that are not supported by the AMD-K6 processor Model 6. For
information about the remaining AMD-K6 registers, see
Chapter 3, “Software Environment” on page 21.
Note: Areas of the register designated as Reserved should not be
modified by software.
Model-Specific
Registers (MSR)
The AMD-K6 processor Model 7 supports two additional MSRs
as compared to the AMD-K6 processor Model 6. The value in the
ECX register selects the MSR to be addressed by the RDMSR
and WRMSR instructions. The values in EAX and EDX are used
as inputs and outputs by the RDMSR and WRMSR instructions.
Table 59 lists the new MSRs and the corresponding value of the
ECX register. Figures 102 and 103 show the MSR formats.
Chapter 24
Software Environment
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