[src/trunk]: src/sys/arch/powerpc/fpu FPSCR[FEX] is not a sticky bit; it is a...

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

details:   https://anonhg.NetBSD.org/src/rev/01f22fa47d84
branches:  trunk
changeset: 935985:01f22fa47d84
user:      rin <rin%NetBSD.org@localhost>
date:      Wed Jul 15 08:29:07 2020 +0000

description:
FPSCR[FEX] is not a sticky bit; it is always cleared when read from
userland via mffs on real hardware.

diffstat:

 sys/arch/powerpc/fpu/fpu_emu.c |  6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diffs (27 lines):

diff -r 19d6b4e6a0d9 -r 01f22fa47d84 sys/arch/powerpc/fpu/fpu_emu.c
--- a/sys/arch/powerpc/fpu/fpu_emu.c    Wed Jul 15 08:14:41 2020 +0000
+++ b/sys/arch/powerpc/fpu/fpu_emu.c    Wed Jul 15 08:29:07 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fpu_emu.c,v 1.28 2020/07/15 08:10:41 rin Exp $ */
+/*     $NetBSD: fpu_emu.c,v 1.29 2020/07/15 08:29:07 rin Exp $ */
 
 /*
  * Copyright 2001 Wasabi Systems, Inc.
@@ -76,7 +76,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: fpu_emu.c,v 1.28 2020/07/15 08:10:41 rin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fpu_emu.c,v 1.29 2020/07/15 08:29:07 rin Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ddb.h"
@@ -571,6 +571,8 @@
                        case    OPC63_MFFS:
                                FPU_EMU_EVCNT_INCR(mffs);
                                DPRINTF(FPE_INSN, ("fpu_execute: MFFS\n"));
+                               /* XXX FEX is not sticky */
+                               fs->fpscr &= ~FPSCR_FEX;
                                memcpy(&fs->fpreg[rt], &fs->fpscr,
                                        sizeof(fs->fpscr));
                                break;