From 315615555c28855516a8a2e77dc8317190a1894d Mon Sep 17 00:00:00 2001
From: Nate Williams <nate@FreeBSD.org>
Date: Thu, 1 Jul 1993 00:17:55 +0000
Subject: [PATCH] Bruce Evans:

The enclosed diffs implement printing of the floating point state for
the version of gdb-3.5 in 386BSD-0.0.  I don't have gdb for 386BSD-0.1
but I've been told that it is also missing this feature.

The changes are small.  Code to read the FP state from the kernel was
#ifdef'ed out, but it essentially works.  Code to change the FP regs
is still #ifdef'ed out.  It is close to working too.  Printing of the
FP regs was broken because hard reg numbers were confused with stack
offsets.

4. The emulator does not handle FP errors right, and it does not
   communicate the emulated FP state to the rest of the kernel, so
   "info float" shows garbage.
---
 gnu/usr.bin/gdb/config/i386bsd-dep.c | 31 +++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/gnu/usr.bin/gdb/config/i386bsd-dep.c b/gnu/usr.bin/gdb/config/i386bsd-dep.c
index 6172cf7c308..d298fb02ac0 100644
--- a/gnu/usr.bin/gdb/config/i386bsd-dep.c
+++ b/gnu/usr.bin/gdb/config/i386bsd-dep.c
@@ -1748,12 +1748,18 @@ print_387_status (status, ep)
   
   top = (ep->status >> 11) & 7;
   
-  printf ("regno  tag  msb              lsb  value\n");
+  printf (" regno     tag  msb              lsb  value\n");
   for (fpreg = 7; fpreg >= 0; fpreg--) 
     {
+      int st_regno;
       double val;
       
-      printf ("%s %d: ", fpreg == top ? "=>" : "  ", fpreg);
+      /* The physical regno `fpreg' is only relevant as an index into the
+       * tag word.  Logical `%st' numbers are required for indexing `p->regs.
+       */
+      st_regno = (fpreg + 8 - top) & 0x7;
+
+      printf ("%%st(%d) %s ", st_regno, fpreg == top ? "=>" : "  ");
       
       switch ((ep->tag >> (fpreg * 2)) & 3) 
 	{
@@ -1763,11 +1769,12 @@ print_387_status (status, ep)
 	case 3: printf ("empty "); break;
 	}
       for (i = 9; i >= 0; i--)
-	printf ("%02x", ep->regs[fpreg][i]);
+	printf ("%02x", ep->regs[st_regno][i]);
       
-      i387_to_double (ep->regs[fpreg], (char *)&val);
+      i387_to_double (ep->regs[st_regno], (char *)&val);
       printf ("  %g\n", val);
     }
+#if 0 /* reserved fields are always 0xffff on 486's */
   if (ep->r0)
     printf ("warning: reserved0 is 0x%x\n", ep->r0);
   if (ep->r1)
@@ -1776,8 +1783,14 @@ print_387_status (status, ep)
     printf ("warning: reserved2 is 0x%x\n", ep->r2);
   if (ep->r3)
     printf ("warning: reserved3 is 0x%x\n", ep->r3);
+#endif
 }
 
+#ifdef __386BSD__
+#define	fpstate		save87
+#define	U_FPSTATE(u)	u.u_pcb.pcb_savefpu
+#endif
+
 #ifndef U_FPSTATE
 #define U_FPSTATE(u) u.u_fpstate
 #endif
@@ -1786,7 +1799,6 @@ i386_float_info ()
 {
   struct user u; /* just for address computations */
   int i;
-#ifndef __386BSD__
   /* fpstate defined in <sys/user.h> */
   struct fpstate *fpstatep;
   char buf[sizeof (struct fpstate) + 2 * sizeof (int)];
@@ -1797,6 +1809,7 @@ i386_float_info ()
   extern int corechan;
   int skip;
   
+#ifndef __386BSD__	/* XXX - look at pcb flags */
   uaddr = (char *)&u.u_fpvalid - (char *)&u;
   if (have_inferior_p()) 
     {
@@ -1804,7 +1817,7 @@ i386_float_info ()
       unsigned int mask;
       
       rounded_addr = uaddr & -sizeof (int);
-      data = ptrace (3, inferior_pid, rounded_addr, 0);
+      data = ptrace (PT_READ_U, inferior_pid, (caddr_t)rounded_addr, 0);
       mask = 0xff << ((uaddr - rounded_addr) * 8);
       
       fpvalid = ((data & mask) != 0);
@@ -1823,6 +1836,7 @@ i386_float_info ()
       printf ("no floating point status saved\n");
       return;
     }
+#endif	/* not __386BSD__ */
   
   uaddr = (char *)&U_FPSTATE(u) - (char *)&u;
   if (have_inferior_p ()) 
@@ -1837,7 +1851,7 @@ i386_float_info ()
       ip = (int *)buf;
       for (i = 0; i < rounded_size; i++) 
 	{
-	  *ip++ = ptrace (3, inferior_pid, rounded_addr, 0);
+	  *ip++ = ptrace (PT_READ_U, inferior_pid, (caddr_t)rounded_addr, 0);
 	  rounded_addr += sizeof (int);
 	}
     } 
@@ -1850,6 +1864,9 @@ i386_float_info ()
       skip = 0;
     }
   
+#ifdef __386BSD__
+  print_387_status (0, (struct env387 *)buf);
+#else
   fpstatep = (struct fpstate *)(buf + skip);
   print_387_status (fpstatep->status, (struct env387 *)fpstatep->state);
 #endif