출처 : http://www.ussg.iu.edu/hypermail/linux/kernel/0402.3/0276.html
IA-32e and AMD64. The software visible ones are:
Fast system
calls:
Syscall/sysret is supported only in 64-bit mode (not in compatibility
mode). Sysenter/Sysexit is supported in both 64-bit and
compatible
mode.
CPUID:
If you look at Table 2-8 of Volume 1, you
will find IA-32e specific
things,
including, GenuineIntel, HT, SSE3,
monitor/mwait, Intel Enhanced
SpeedStep,
and cmpxchg16b.
The
function 8000_0001h doesn't duplicate standard-feature bits from
function 1
in EDX. It sets only the new features that are implemented.
MSRs:
Not
all MSRs are architectural, and IA-32e does not implement SYSCFG,
TOP_MEM,
TOP_MEM2, for example. MSR usage should be vendor specific
and
be guarded
with CPUID.Model
Fast-FXSAVE/FXRSTOR:
IA-32e always saves all of the
FP state on FXSAVE/FXRSTOR. Does not
support FXSAVE/FXRSTOR with reduced FP
state.
Microcode Update:
IA-32e supports microcode update as the
32-bit mode does, as you
already
found the discussions in the mailing
list.
NX (No-Execute) bit:
Initial implementation will not support the
NX bit.
BSF/BSR when source is 0 & operand size is 32:
In 64-bit
mode, the processor sets ZF, and the upper 32 bits of
the destination are
undefined. Should always check the ZF or do not
use
32-bit operand
size.
Near branch with 66H prefix:
As documented in PRM the behavior
is implementation specific and
should
avoid using 66H prefix on near
branches.
Not supported in IA-32e
=======================
3DNow
instructions (including prefecthw or prefetch with the opcode 0f
0d)
IA-32e가 x86-64와 다른 점입니다.
NX 비트는 채용을 안했군요.
그러니 마소가 AMD에 sse3를 공개하라고 협박을...(사견입니다. -_-;;)
IA-32e는 Systemcall/Systemret 은 64비트에서만 가능하고, 마이크로코드 업데이트 기능은 그대로 가져오고
있으며, 가까운 브랜치(분기)에 대해 0x66 프레픽스를 사용하지 않는다고 합니다. 등등등... -_-;;
IA-32e 에서 지원되지 않는 명령은 3D Now! 명령중 2개라고...
참고하시길...
