[src/trunk]: src/sys/arch/sun3/sun3 Bring FPU probe code from atari/fpu.c and...

[tsutsui <tsutsui%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3942b7a7f97e
branches:  trunk
changeset: 503238:3942b7a7f97e
user:      tsutsui <tsutsui%NetBSD.org@localhost>
date:      Sat Feb 03 14:30:42 2001 +0000

description:
Bring FPU probe code from atari/fpu.c and remove unneeded includes.

diffstat:

 sys/arch/sun3/sun3/fpu.c |  78 ++++++++++++++++++++++++++++++++----------------
 1 files changed, 52 insertions(+), 26 deletions(-)

diffs (128 lines):

diff -r bb56f3567ead -r 3942b7a7f97e sys/arch/sun3/sun3/fpu.c
--- a/sys/arch/sun3/sun3/fpu.c  Sat Feb 03 13:25:00 2001 +0000
+++ b/sys/arch/sun3/sun3/fpu.c  Sat Feb 03 14:30:42 2001 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fpu.c,v 1.15 1998/02/05 04:57:34 gwr Exp $     */
+/*     $NetBSD: fpu.c,v 1.16 2001/02/03 14:30:42 tsutsui Exp $ */
 
 /*-
  * Copyright (c) 1996 The NetBSD Foundation, Inc.
@@ -43,16 +43,10 @@
 
 #include <sys/param.h>
 #include <sys/systm.h>
-#include <sys/time.h>
-#include <sys/kernel.h>
-#include <sys/device.h>
 
-#include <machine/psl.h>
 #include <machine/cpu.h>
 #include <machine/frame.h>
-#include <machine/mon.h>
 
-#include <sun3/sun3/interreg.h>
 #include <sun3/sun3/machdep.h>
 
 static int fpu_probe __P((void));
@@ -63,27 +57,30 @@
 #else
        "no math support",      /* 0 */
 #endif
-       "mc68881",                      /* 1 */
-       "mc68882",                      /* 2 */
-       "?" };
+       "mc68881",              /* 1 */
+       "mc68882",              /* 2 */
+       "mc68040 internal",     /* 3 */
+       "mc68060 internal",     /* 4 */
+       "unknown type" };       /* 5 */
 
 void
 initfpu()
 {
        char *descr;
+       int maxtype = sizeof(fpu_descr) / sizeof(fpu_descr[0]) - 1;
 
        /* Set the FPU bit in the "system enable register" */
        enable_fpu(1);
 
        fputype = fpu_probe();
-       if ((0 <= fputype) && (fputype <= 2))
-               descr = fpu_descr[fputype];
-       else
-               descr = "unknown type";
+       if (fputype < 0 || fputype > maxtype)
+               fputype = FPU_UNKNOWN;
+
+       descr = fpu_descr[fputype];
 
        printf("fpu: %s\n", descr);
 
-       if (fputype == 0) {
+       if (fputype == FPU_NONE) {
                /* Might as well turn the enable bit back off. */
                enable_fpu(0);
        }
@@ -93,22 +90,51 @@
 fpu_probe()
 {
        label_t faultbuf;
-       struct fpframe null_fpf;
+       struct fpframe fpframe;
+       u_char b;
 
        nofault = &faultbuf;
        if (setjmp(&faultbuf)) {
                nofault = NULL;
-               return(0);
+               return FPU_NONE;
        }
-       bzero(&null_fpf, sizeof(null_fpf));
-       /* This will trap if there is no FPU present. */
-       m68881_restore(&null_fpf);
+
+       /*
+        * Synchronize FPU or cause a fault.
+        * This should leave the 881/882 in the IDLE state,
+        * so we can determine which we have by
+        * examining the size of the FP state frame.
+        */
+       asm("fnop");
+
        nofault = NULL;
 
-       /* XXX - See atari version. */
-#ifdef _SUN3X_
-       return(2);
-#else
-       return(1);
-#endif
+       /* Presumably, this will not cause a fault--the fnop should
+        * have if this will. We save the state in order to get the
+        * size of the frame.
+        */
+       asm("fsave %0@" : : "a" (&fpframe) : "memory");
+
+       b = fpframe.fpf_fsize;
+
+       /*
+        * Now, restore a NULL state to reset the FPU.
+        */
+       fpframe.fpf_null = 0;
+       fpframe.fpf_idle.fpf_ccr = 0;
+       m68881_restore(&fpframe);
+
+       /*
+        * The size of a 68881 IDLE frame is 0x18
+        *           and 68882 frame is 0x38
+        */
+       if (b == 0x18)
+               return FPU_68881;
+       if (b == 0x38)
+               return FPU_68882;
+
+       /*
+        * If it's not one of the above, we have no clue what it is.
+        */
+       return FPU_UNKNOWN;
 }