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|    comp.lang.asm.x86    |    Ahh, the lost art of x86 assembly    |    4,675 messages    |
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|    Message 4,414 of 4,675    |
|    R.Wieser to All    |
|    Re: FPU (x87) code debugging.    |
|    09 Aug 21 18:11:26    |
      From: address@nospicedham.not.available              Robert,              > It is a purer memory test.              In what way ? And mind you, I already adressed that.              > I thought there was question of whether FXSAVE was available       > or supported on your CPU.              As I could not get a working FXSAVE encoding I started to doubt.              > This checks opcode encoding too.              No need for that, as those two bytes came from an opcode list. The only       unknown part was the adressing of the target memory.              > All GP registers should be available at all times.              Agreed. But it is an extra factor, and as such interference.              > Encoding should not be a guessing game.              What makes you think I was ? I tried a few different R/M encodings       (while providing different registers), and none of them wanted to work.       Hence my (above) described doubt to if the command was available on my       'puter/processor. (read: I was quite certain I did it "by the book")              But when you /know/ something ought to work and you cannot make it so than a       pragmatic approach will be called for. Which includes throwing everything       and the kitchen sink at it to see if /something/ will work. And from that       try to reason back why it does and where you went wrong with the first       attempts.              > x86 has quirky indirect addressing modes that       > are unlikely to yield to trial-and-error.              True. But I would not be looking for those. Just a simple one that       /does/ function. From that foot-in-the-door the rest often follows.              And that is effectivily what happened when Wolfgang supplied me with a       working encoding for FXSAVE [EDI] : while trying to match the 0x07 to the       mod,reg,r/m tables I had used I realized I had been using the wrong one. It       was as simple as that.              Regards,       Rudy Wieser              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)    |
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