1.\" 2.\" Copyright (c) 1993 Christopher G. Demetriou 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. All advertising materials mentioning features or use of this software 14.\" must display the following acknowledgement: 15.\" This product includes software developed by Christopher G. Demetriou. 16.\" 3. The name of the author may not be used to endorse or promote products 17.\" derived from this software withough specific prior written permission 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29.\" 30.\" from: npx.4,v 1.1 1993/08/06 10:58:03 cgd Exp 31.\" $Id$ 32.\" 33.Dd August 28, 1993 34.Dt NPX 4 i386 35.Os FreeBSD 36.Sh NAME 37.Nm npx 38.Nd 39Numeric Processing Extension coprocessor and emulator 40.Sh SYNOPSIS 41.Cd "options MATH_EMULATE" 42.\" XXX this is awful hackery to get it to work right... -- cgd 43.Cd "device npx0 at isa? port" \&"IO_NPX0\&" tty irq 13 vector npxintr 44.Sh DESCRIPTION 45The 46.Nm npx 47driver enables the use of the system's Numeric Processing Extension 48coprocessor, 49if one is present. Numeric processing extensions are present in 50systems with 51.Nm 486DX 52CPUs and in systems with 53.Nm 387 54or 55.Nm 487SX 56coprocessors. The 57.Nm npx 58driver is required for proper system functioning regardless 59of whether or not a NPX is present. 60.Pp 61If there is no NPX present in the system, the "MATH_EMULATE" 62option must be defined in the kernel configuration file. 63It will provide support for the instructions normally executed 64by the NPX. If there is no NPX in the system and the kernel 65is not built with math emulation, the system will not boot. 66.Sh CAVEATS 67The emulator is much slower than the NPX coprocessor. 68This will result in poor floating-point math performance 69if the emulator must be used. 70.Sh BUGS 71There are lots of them, especially on cheap motherboards. In particular, 72some motherboards do not have the interrupt lines from the NPX to 73the CPU wired properly. If this is the case, the emulator must be used 74if consistent system operation is desired. 75.Pp 76Emulation of the transcendental functions instructions is incorrect. 77Emulation of other instructions is suspect. 78