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Re: modernizing npx(4)
On Jun 1, 8:21pm, Andrew Doran wrote:
} On Wed, Jan 09, 2008 at 06:54:50PM -0600, David Young wrote:
} > It is my understanding that since we do not support the 80386 any more,
} > there is no need to support npx at irq 13, since every x86 processor
} > since the 80486 is capable of reporting FP errors by using exception 16.
} > Is it ok if I get rid of the vestiges of irq 13 handling,
} Sounds good to me. It could share amd64's fpu.c. The only isuse I can think
} of is that fpu.c assumes presence of the fxsave/fxrstor instructions (SSE).
} > and move npx0 from isa0 to mainbus0? Let me know.
} The cpu attachment covers it. As the exception handling suggests the FPU has
} not been seperate since the 486 - the 487 was IIRC actually just a 486DX.
Very close. It actually had an extra pin/signal to tell the
motherboard to disable the 486SX soldered to the board. Of course many
manufacturers just stuck the 486SX in a socket, so you could just pull
it out and replace it with a 486DX.
}-- End of excerpt from Andrew Doran
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