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: npx.4,v 1.4 1997/02/22 13:25:36 peter Exp $ 32.\" 33.Dd August 28, 1993 34.Dt NPX 4 i386 35.Os FreeBSD 36.Sh NAME 37.Nm npx 38.Nd Numeric Processing Extension coprocessor and emulator 39.Sh SYNOPSIS 40.Cd "options MATH_EMULATE" 41.\" XXX this is awful hackery to get it to work right... -- cgd 42.Cd "device npx0 at isa? port IO_NPX tty irq 13" 43.Sh DESCRIPTION 44The 45.Nm npx 46driver enables the use of the system's Numeric Processing Extension 47coprocessor, 48if one is present. Numeric processing extensions are present in 49systems with 50.Sy 486DX 51CPUs and in systems with 52.Sy 387 53or 54.Sy 487SX 55coprocessors. The 56.Nm npx 57driver is required for proper system functioning regardless 58of whether or not a NPX is present. 59.Pp 60If there is no NPX present in the system, the "MATH_EMULATE" 61option must be defined in the kernel configuration file. 62It will provide support for the instructions normally executed 63by the NPX. If there is no NPX in the system and the kernel 64is not built with math emulation, the system will not boot. 65.Sh CAVEATS 66The emulator is much slower than the NPX coprocessor. 67This will result in poor floating-point math performance 68if the emulator must be used. 69.Sh BUGS 70There are lots of them, especially on cheap motherboards. In particular, 71some motherboards do not have the interrupt lines from the NPX to 72the CPU wired properly. If this is the case, the emulator must be used 73if consistent system operation is desired. 74.Pp 75Emulation of the transcendental functions instructions is incorrect. 76Emulation of other instructions is suspect. 77