[9fans] fpu emulation

[9fans] fpu emulation

[Quinn Dunkan]

If there's no FPU detected, does plan9 attempt to emulate one?  How can you
tell if it's emulating?

Here's what acid has to say:

826: math coprocessor emulation lua_tonumber+0x40   FMOVD   0x4(DX),F0
Notes pending:
    sys: fp: invalid fppc=0x13ed7

My current theory is that somehow plan 9 missed the FPU on my processor (AMD
K6-3) and enabled software FPU, which, due to little exercise, is buggy.



Also, acme's stmt() seems to get caught in an endless loop if the debugee gets
a note.  The PC never changes, so it keeps trying to execute the current one.

Speaking of acid, the documented acid functions fpr() and Fpr() don't seem to
exist.  I can get them with *F0\F, etc., but if I just type F0 instead of
getting an address it prints an empty string.

Re: [9fans] fpu emulation

[jmk]

On Sun Jun 24 23:53:27 EDT 2001, quinn@hork.ugcs.caltech.edu wrote:
> If there's no FPU detected, does plan9 attempt to emulate one?  How can you
> tell if it's emulating?
> 
> Here's what acid has to say:
> 
> 826: math coprocessor emulation lua_tonumber+0x40   FMOVD   0x4(DX),F0
> Notes pending:
>     sys: fp: invalid fppc=0x13ed7
> 
> My current theory is that somehow plan 9 missed the FPU on my processor (AMD
> K6-3) and enabled software FPU, which, due to little exercise, is buggy.
> 

there is no software fp emulation for the x86.