[src/trunk]: src/sys/arch/mvme68k/mvme68k On exit from syscalls, don't trash ...

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

details:   https://anonhg.NetBSD.org/src/rev/fa8a601fd325
branches:  trunk
changeset: 499948:fa8a601fd325
user:      scw <scw%NetBSD.org@localhost>
date:      Sat Dec 02 17:00:46 2000 +0000

description:
On exit from syscalls, don't trash %A0 if the process is
using the COMPAT_AOUT_M68K emulation package.

diffstat:

 sys/arch/mvme68k/mvme68k/trap.c |  16 ++++++++++++++--
 1 files changed, 14 insertions(+), 2 deletions(-)

diffs (38 lines):

diff -r 7c38b2cd2511 -r fa8a601fd325 sys/arch/mvme68k/mvme68k/trap.c
--- a/sys/arch/mvme68k/mvme68k/trap.c   Sat Dec 02 16:57:41 2000 +0000
+++ b/sys/arch/mvme68k/mvme68k/trap.c   Sat Dec 02 17:00:46 2000 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: trap.c,v 1.50 2000/12/02 13:45:14 scw Exp $    */
+/*     $NetBSD: trap.c,v 1.51 2000/12/02 17:00:46 scw Exp $    */
 
 /*
  * Copyright (c) 1988 University of Utah.
@@ -93,6 +93,10 @@
 extern struct emul emul_linux;
 #endif
 
+#ifdef COMPAT_AOUT_M68K
+extern struct emul emul_netbsd_aoutm68k;
+#endif
+
 int    writeback __P((struct frame *fp, int docachepush));
 void   trap __P((int type, u_int code, u_int v, struct frame frame));
 void   syscall __P((register_t code, struct frame frame));
@@ -1131,8 +1135,16 @@
        error = (*callp->sy_call)(p, args, rval);
        switch (error) {
        case 0:
-               frame.f_regs[D0] = frame.f_regs[A0] = rval[0];
+               frame.f_regs[D0] = rval[0];
                frame.f_regs[D1] = rval[1];
+#ifdef COMPAT_AOUT_M68K
+               /*
+                * Some pre-m68k ELF libc assembler stubs assume
+                * %a0 is preserved across system calls...
+                */
+               if (p->p_emul != &emul_netbsd_aoutm68k)
+                       frame.f_regs[A0] = rval[0];
+#endif
                frame.f_sr &= ~PSL_C;   /* carry bit */
                break;
        case ERESTART: