8400 E0的两条新指令 XSAVE/XRSTOR 有啥作用呢？

fonfon

8400 E0的两条新指令 XSAVE/XRSTOR 有啥作用呢？
没搞明白，请教高手

fonfon

没人回答？看来这个比较专业哦{shocked:]

hanzify

xsave/xrstor manages the existing and future processor extended states in x86 architecutre.
谁翻译一下。。。

[MB] l1

从内存保存/恢复某些扩展寄存器状态，intel.com大把教程指南，基本上需要了解的开发人员都会自己找资料，找不到or看不懂的也不用多管，有软件照用就是。

gunnerng

有什么用途呢，新版E5200都有~~

铁道虫

xsave/xrstor manages the existing and future processor extended states in x86 architecutre.
谁翻译一下。。。
hanzify 发表于 2008-9-8 16:41

在X86架构下，xsave/xrstor 管理存在和未来的处理器扩展状态

搞不懂。这个(existing and future processor extended states 存在和未来的处理扩展状态)估计是一个专业术语。

wowman

有意思，这2条指令到底改进CPU的哪些方面，能提高性能吗

woriamd

提高多媒体解码时候的性能的。不过感觉提高不大。估计需要播放器对其优化才行

wowman

原来如此，谢谢LS

nfsking2

貌似不是吧.....
这两个指令是配合PSI用的（Power Status Indicator）

The xsave/xrstor infrastructure is mainly for extensibility with respect to the "processor extened
states" since more extended states are coming
With the patch, XSAVE-aware HVM guest can make use of the coming extended features.

And Intel SDM 3A: chatper 12 ( SYSTEM PROGRAMMING FOR INSTRUCTION SET EXTENSIONS AND PROCESSOR EXTENDED
STATES) supplies a generic description.

BTW, some CPU, such as Intel Core 2 Duo Processor E8500, E8400, have had the support of the XSAVE/XRSTOR instructions.

For now, the xsave_area is at least 512 + 64 (the xsave header) = 576 bytes in length, though the first 512
bytes are completely compatible with the legacy 512-byte arch.guest_context.fpu_ctxt; actually we
also have to save the per-vcpu 64-bit "xfeature_mask", and the gloabal variables
"xsave_cntxt_max_size, xfeature_low, xfeature_high" (imagine different CPU has different XSAVE
capability). So I think we have to extend the current save/restore format.

4479237

看来C1的E8200没有了