usr/src/sys/i386/isa/npx.c

/*-
 * Copyright (c) 1990 William Jolitz.
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)npx.c       7.2 (Berkeley) %G%
 */
#include "npx.h"
#if NNPX > 0

#include "param.h"
#include "systm.h"
#include "conf.h"
#include "file.h"
#include "proc.h"
#include "machine/cpu.h"
#include "machine/pcb.h"
#include "machine/trap.h"
#include "ioctl.h"
#include "machine/specialreg.h"
#include "i386/isa/isa_device.h"
#include "icu.h"
/*
 * 387 and 287 Numeric Coprocessor Extension (NPX) Driver.
 */

int     npxprobe(), npxattach(), npxintr();
struct  isa_driver npxdriver = {
        npxprobe, npxattach, "npx",
};

struct proc *npxproc;   /* process who owns device, otherwise zero */
struct pcb *npxpcb;     /* owners context structure */
static npxexists;
extern long npx0mask;

/*
 * Probe routine - look device, otherwise set emulator bit
 */
npxprobe(dvp)
        struct isa_device *dvp;
{       static status, control;

#ifdef lint
        npxintr();
#endif

        /* insure EM bit off */
        asm("   fninit ");      /* put device in known state */

        /* check for a proper status of zero */
        status = 0xa5a5;
        asm ("  fnstsw  %0 " : "=m" (status) : "m" (status) );

        if (status == 0) {

                /* good, now check for a proper control word */
                control = 0xa5a5;
                asm ("  fnstcw %0 " : "=m" (control) : "m" (control));

                if ((control&0x103f) == 0x3f) {
                        /* then we have a numeric coprocessor */
                /* XXX should force an exception here to generate an intr */
                        return (1);
                }
        }

/* insure EM bit on */
        return (0);
}

/*
 * Attach routine - announce which it is, and wire into system
 */
npxattach(dvp)
        struct isa_device *dvp;
{

        npxinit(0x262);
        /* check for ET bit to decide 387/287 */
        /*outb(0xb1,0);         /* reset processor */
        npxexists++;
        npx0mask = dvp->id_irq;
}

/*
 * Initialize floating point unit, usually after an error
 */
npxinit(control) {

        if (npxexists == 0) return;


        load_cr0(rcr0() & ~CR0_EM);     /* stop emulating */
#ifdef INTEL_COMPAT
        asm ("  finit");
        asm("   fldcw %0" : : "g" (control));
        asm("   fnsave %0 " : : "g" (curpcb->pcb_savefpu) );
#else
        asm("fninit");
        asm("   fnsave %0 " : : "g" (curpcb->pcb_savefpu) );
#endif
        load_cr0(rcr0() | CR0_EM);      /* start emulating */

}

/*
 * Load floating point context and record ownership to suite
 */
npxload() {

        if (npxproc) panic ("npxload");
        npxproc = curproc;
        npxpcb = curpcb;
        asm("   frstor %0 " : : "g" (curpcb->pcb_savefpu) );
}

/*
 * Unload floating point context and relinquish ownership
 */
npxunload() {

        if (npxproc == 0) panic ("npxunload");
        asm("   fsave %0 " : : "g" (npxpcb->pcb_savefpu) );
        npxproc = 0 ;
}

/*
 * Record information needed in processing an exception and clear status word
 */
npxintr(frame) struct intrframe frame; {
        struct trapframe tf;

        outb(0xf0,0);           /* reset processor */

        /* sync state in process context structure, in advance of debugger/process looking for it */
        if (npxproc == 0 || npxexists == 0) panic ("npxintr");
        asm ("  fnsave %0 " : : "g" (npxpcb->pcb_savefpu) );

        /*
         * Prepair a trap frame for our generic exception processing routine, trap()
         */
        bcopy(&frame.if_es, &tf, sizeof(tf));
        tf.tf_trapno = T_ARITHTRAP;
#ifdef notyet
        /* encode the appropriate code for detailed information on this exception */
        tf.tf_err = ???;
#endif
        trap(tf);

        /*
         * Restore with any changes to superior frame
         */
        bcopy(&tf, &frame.if_es, sizeof(tf));

        /* clear the exception so we can catch others like it */
        asm ("  fnclex");
}

/*
 * Implement device not available (DNA) exception
 */
npxdna() {

        if (npxexists == 0) return(0);
        if (!(curpcb->pcb_flags & FP_WASUSED)
            ||(curpcb->pcb_flags & FP_NEEDSRESTORE)) {
                load_cr0(rcr0() & ~CR0_EM);     /* stop emulating */
                asm("   frstor %0 " : : "g" (curpcb->pcb_savefpu));
                curpcb->pcb_flags |= FP_WASUSED | FP_NEEDSSAVE;
                curpcb->pcb_flags &= ~FP_NEEDSRESTORE;
                npxproc = curproc;
                npxpcb = curpcb;

                return(1);
        }
        return (0);
}
#endif