Author: Robert Hyatt
Date: 08:48:47 03/06/03
Go up one level in this thread
On March 05, 2003 at 22:38:44, Jeremiah Penery wrote: >On March 05, 2003 at 18:26:10, Robert Hyatt wrote: > >>The point of my comments is that Intel sets a sort of standard, and if someone >>follows along, >>but are not quite all there, it can cause problems. I had this problem with >>Cyrix years ago as >>their 387's were actually more accurate than Intel's, not to mention faster. >>And they would >>make every diagnostic program on the planet sound the alarm with floating point >>errors. :) >> >>And I got tired of the phone calls asking about it and quit recommending them. >>:) > >Why should a company be penalized for making a better product? Making a processor that is "PII-compatible" but really isn't, is "better"? My point. > >>>>If everyone was a compiler expert, this might be forseeable. But they aren't. >>>>And I doubt >>>>most would think that -target=pentiumII would break a processor that is supposed >>>>to be >>>>compatible. >>>> >>>>Can I say more? >>> >>>A lot of the average programmers probably don't even know to use a specific >>>processor target (when using GCC), or they use some other compiler. I'd expect >>>someone who uses specific processor targets in their compile to have some basic >>>understanding of assembly. >> >>I wouldn't. If you look at the simple help files, you might see: > >And you think even 5% of people look at help files? :) Again, my point. I don't think .01% of people look at help files. They would assume that their PII-compatible processor really is PII-compatible and contact me about a bug in _my_ program. However, I'll bet that anybody compiling a C program they write will do a "man gcc" on a unix box because they have heard about -O and want to see what else there is to make their handy-dandy chess engine as fast as possible. > >>"-target=pentiumII" This causes the compiler to optimize the program for >>optimum >>performance on the intel Pentium II processor. (hypothetical option and >>explanation >>of course.) >> >>That could get any beginner to try it and it would work. And introduce an >>unknown >>incompatibility with AMD. >> >>> >>>>For the streetlight issue, the streetlight is not hanging over the street in >>>>plain sight. It is >>>>buried under the light pole, with a door with a combination lock on it that has >>>>to be opened >>>>so it can be seen. Do you expect John/Jane Doe to know that when there is no >>>>sign on the >>>>pole that says "look here for compatibility issues"??? >>>> >>>>I don't. >>> >>>I'm not sure I expect Jonn/Jane Doe to understand that you have to even look for >>>traffic, whether the light says 'WALK' or not. Obviously, there are a lot of >>>people who fit in that category. >> >>The problem here is that they don't even know there _is_ traffic. Who would >>think >>that the compiler produces an instruction that a compatible processor doesn't >>support? >>They don't even understand assembly language, much less instructions, much less >>any >>more details that are necessary to even understand that there might be a >>problem. >> >>Remember, that intellect represents 99%+ of all the computer users on the >>planet. > >And probably 99.9% of those people are not going to using anything but >store-bought programs, which will check for processor support (or use basic >386-like instructions that MSVC emits), so they never run into this kind of Well over 1M _different_ IP addresses has downloaded Crafty. When you consider that places like AOL.com appear to use one IP for _many_ customers, you can figure that maybe that number is 2M or higher. if .1% = 2M, then you must believe there are 2B computers on the planet. I do a _lot_ of continuing education courses here at UAB. Which puts me into contact with "rank beginner" type computer users. And _all_ have downloaded freeware programs. From screen-shot capturers, to chat programs, to you-name-it. I'd bet that way over 50% of all computer users have sampled freeware programs, which makes this an issue again. Of course AMD might have fixed the cmov problem in later versions, I don't know since I don't use 'em. But the mine was laid and armed, and way more than you might guess stepped on it. As far as using "basic 386 instructions" that _really_ makes me want to puke. Why do you think the Intel folks added the new instructions? Just to be incompatible? Or to speed things up? I bugged the GCC folks for a _long_ time about cmov, for example, because I had used a similar instruction on the early alpha processors and thought it was an interesting solution to a known problem. Instead of using the new stuff, you seem to be suggesting that it is better to only use what is available on _both_ processors, which (to me) is senseless. >problem.
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