3-28 Software Environment and Extensions
AMD-K5 Processor Technical Reference Manual 18524C/0—Nov1996
3.2.5 Hardware Configuration Register (HWCR)
The Hardware Configuration Register (HWCR) contains con-
figuration bits that control miscellaneous debugging functions.
The HWCR can be written or read with the WRMSR or
RDMSR instruction when the ECX register contains the value
83h.
For details on the HWCR, see Section 7.1 on page 7-3.
3.3 New Instructions
In addition to supporting all of the 486 processor instructions,
the AMD-K5 processor implements the following instructions:
■ CPUID
■ CMPXCHG8B
■ MOV to and from CR4
■ RDTSC
■ RDMSR
■ WRMSR
■ RSM
■ Illegal instruction (reserved opcode)