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Mixed updates: 

- isa => nexus
- flags
- GPL_MATH_EMULATE
- document breakage of non-GPL emulator since we use new compiler.
- break lines in paragraohs I touched so that sentenses start on new
  lines.
This commit is contained in:
Martin Cracauer 1999-12-16 08:05:09 +00:00
parent 22e1dc858b
commit 25aa5b8459
1 changed files with 28 additions and 12 deletions
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40
share/man/man4/man4.i386/npx.4
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@ -37,9 +37,11 @@
.Nm npx
.Nd Numeric Processing Extension coprocessor and emulator
.Sh SYNOPSIS
.Cd "device npx0 at nexus? port IO_NPX flags 0x0 irq 13"
.Cd "options MATH_EMULATE"
.Cd "options GPL_MATH_EMULATE"
.\" XXX this is awful hackery to get it to work right... -- cgd
.Cd "device npx0 at isa? port IO_NPX irq 13"
.\" What the heck does he mean? - cracauer
.Sh DESCRIPTION
The
.Nm npx
@ -57,20 +59,34 @@ coprocessors. The
driver is required for proper system functioning regardless
of whether or not a NPX is present.
.Pp
If there is no NPX present in the system, the "MATH_EMULATE"
option must be defined in the kernel configuration file.
It will provide support for the instructions normally executed
by the NPX. If there is no NPX in the system and the kernel
is not built with math emulation, the system will not boot.
If there is no NPX present in the system, the "MATH_EMULATE" or
"GPL_MATH_EMULATE" option must be defined in the kernel configuration
file.
It will provide support for the instructions normally executed by the
NPX.
If there is no NPX in the system and the kernel is not built with math
emulation, the system will not boot.
.Pp
For a description of the possible "flags" values see the LINT kernel
configuration file.
.Sh CAVEATS
The emulator is much slower than the NPX coprocessor.
This will result in poor floating-point math performance
if the emulator must be used.
.Sh BUGS
There are lots of them, especially on cheap motherboards. In particular,
some motherboards do not have the interrupt lines from the NPX to
the CPU wired properly. If this is the case, the emulator must be used
if consistent system operation is desired.
.Pp
Emulation of the transcendental functions instructions is incorrect.
The non-GPL emulator does not support the whole set of npx
instructions.
It is sufficient for booting and configuring a system, but it cannot
support a system with normal workload unless care is taken to compile
the whole system (including third-party packages) with compiler
options that avoid the use of the non-emulated instructions.
.Sh BUGS
There are lots of them, especially on old cheap motherboards.
In particular, some motherboards do not have the interrupt lines from
the NPX to the CPU wired properly.
If this is the case, the emulator must be used if consistent system
operation is desired.
.Pp
Emulation of the transcendental functions instructions in the non-GPL
emulator is incorrect.
Emulation of other instructions is suspect.