npx - Numeric Processing Extension coprocessor and emulator
npx0 at isa? port "IO_NPX0" irq 13
The npx driver enables the use of the system's Numeric Processing Extension
coprocessor, if one is present. Numeric processing extensions are
present in systems with 486DX CPUs and in systems with 387
or 487SX coprocessors.
The npx driver is required for proper system
of whether or not a NPX is present.
If there is no NPX present in the system option
GPL_MATH_EMULATE must be
defined in the kernel configuration file. It will provide
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
The emulator is much slower than the NPX coprocessor. This
in poor floating-point math performance if the emulator must
There are lots of them, especially on cheap motherboards.
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.
Emulation of the transcendental functions instructions is
of other instructions is suspect.
OpenBSD 3.6 August 6, 1993
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