date and time created 91/04/03 12:32:20 by william

[unix-history] / usr / src / sys / i386 / isa / npx.c

/*
* Copyright (c) 1990 W. Jolitz
* @(#)npx.c    1.3 (Berkeley) %G%
*/
#include "npx.h"
#if     NNPX > 0

#include "param.h"
#include "systm.h"
#include "conf.h"
#include "file.h"
#include "dir.h"
#include "user.h"
#include "ioctl.h"
#include "vm.h"
#include "machine/pte.h"
#include "machine/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 */
extern struct user npxutl;      /* owners user structure */
extern struct pte Npxmap[];     /* kernel ptes mapping owner's user structure */

/*
* 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 */
}

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

       asm ("  fninit");
       asm("   fldcw %0" : : "g" (control));

}

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

       if (npxproc) panic ("npxload");
       npxproc = u.u_procp;
       uaccess(npxproc, Npxmap, &npxutl);
       asm("   frstor %0 " : : "g" (u.u_pcb.pcb_savefpu) );
}

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

       if (npxproc == 0) panic ("npxunload");
       asm("   fsave %0 " : : "g" (npxutl.u_pcb.pcb_savefpu) );
       npxproc = 0 ;
}

/*
* Record information needed in processing an exception and clear status word
*/
npxexcept() {

       /* save state in appropriate user structure */
       if (npxproc == 0) panic ("npxexcept");
       asm ("  fsave %0 " : : "g" (npxutl.u_pcb.pcb_savefpu) );

       /*
        * encode the appropriate u_code for detailed information
        * on this exception
        */

       /* signal appropriate process */
       psignal (npxproc, SIGFPE);

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

/*
* Catch AT/386 interrupt used to signal exception, and simulate trap()
*/
npxintr() {
       outb(0xf0,0);
       pg("npxintr");
}

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