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FPU Emulator

From: dmurd...@mast.QueensU.CA (Duncan Murdoch)...
Quote
>You didn't say which TP version you're using.  In some of them, >the

emulator had a bug, and didn't check for overflow at all.
Quote

>The Pentium still has a 8 entry floating point stack, but some
>programs extend the stack into memory, by copying things out >whenever a

stack fault occurs.

I am using TP6 under Windows 95 (MSDOS mode- rumour has it that TP7 runs in
a DOS-box. That's probably the best reason to upgrade to TP7 I've heard
yet...!)

I don't know how Windows 95 handles FP operations. I'm just toggling the TP
Emulator on and off using the "87" environment variable and observing very
different results.

Chris.

 

Re:FPU Emulator


Quote
cjran...@vossnet.co.uk(Chris Rankin) wrote:
>From: dmurd...@mast.QueensU.CA (Duncan Murdoch)...
>>You didn't say which TP version you're using.  In some of them, >the
>emulator had a bug, and didn't check for overflow at all.

>>The Pentium still has a 8 entry floating point stack, but some
>>programs extend the stack into memory, by copying things out >whenever a
>stack fault occurs.

>I am using TP6 under Windows 95 (MSDOS mode- rumour has it that TP7 runs in
>a DOS-box. That's probably the best reason to upgrade to TP7 I've heard
>yet...!)

Yes, TP6 had this bug.  From TP6BUGS7.ZIP (available on
garbo.uwasa.fi):

The coprocessor emulator doesn't check properly for internal stack

overflow; it just wraps around and trashes the top of the stack
segment.
(Fixed in BP 7.)

I can't say for sure that TP 7 works in a DOS box in Win95, but I
expect it should, since I use BP 7 that way quite a bit.

Duncan Murdoch

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