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Is opcode 0x82 valid?

I have two different versions of "IA-32 Intel Architecture Software Developer's Manual". In Table A-2 "One-byte Opcode Map", one says 0x82 is "Ev, Ib"(the same as 0x83)but the other says 0x82 is "Eb, Ib"(the same as 0x80). But in "instruction set reference", it seems 0x82 is never used(for example, instruction __add__). So, is 0x82 a valid opcode? If it is, how should I decode it?


Message Edited by minwang on 10-21-2004 05:53 PM

how is physical memory "seen" by cpu?

Suppose I have 16M physical memory in my system. Is it true that cpu accesses all the physical memory by putting 0x000000-0xffffff on its address bus? If it is true, does it mean the minimal memory requirement for DOS is 1M(because 640k-1M area is mandatory for mapping for various purposes)? And how does the mapping work?Is it something like when system power up, it reads BIOS into physical memory area reserved for BIOS mapping?


Message Edited by minwang on 10-12-2004 01:03 AM

EOF for Shared Bus Architecture?

Last 2 years of Intel in single CPU space were not too bad. Hyperthreading, faster FSB, SSE3 etc.
But what about Dual and Quad CPU x86 systems ?
How long Intel will be sitting on shared bus architecture? It is really major problem, and no amount of cache on Xeon CPUs or FSB speedup is going to solve it. Hypertransport is flourishing meanwhile on multi-CPU IBM/Apple and AMD systems.
So, where is Intel going with shared bus/memory architecture? Will we be it the same place 2 years from now?
Cmon time to make some changes. Good CPUs need good memory bus.

About FPU/SSE determinism

I have a question about determinism in FPU and SSE computations. Suppose thatI have a mixed sequence ofboth FPUand SSE instructions. Then I run it on different types of Intel microprocessors keeping the same starting conditions (general registers, FPU registers, memory etc). Will the final results be bit-by-bit equalon all processors? Are there any rules to predict and avoid undetermined results of FPU or SSE computations?

Thank you.

2.4ghz/533 fsb

Im having a problem with my 2.4 533 fsb p4. I bought this 2 years ago so i theew away my box and stuff for the motherbored i know i bought it from www.outpost.com. Its soppose to be 2.4 but when i go to my computer to view systems information it says 1.77 ghz. I was wondering if anyone knows how to fix it because my computer isent peforming as well.
I have in my computer
ait 9600xt 256 mb 128 bit
pc 2700 512 mb
cdrw sony 52x32x52x16
120 gb western digital harddrive

IA32_CTL Model Specific Register


My question is regarding the Model Specific Registers (MSRs) of the Pentium 4 family. I have been refering to the following application note -

IA-32 Intel Architecture, Software Developers Manual,
Volume 3: System Programming Guide

The MSR "IA32_CTL" located at address 0x17B (379)isdescribed asthe "Machine Check Feature Enable".

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