[src/trunk]: src/sys/arch/x86/x86 Use a switch, we can (and will) optimize ea...

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

details:   https://anonhg.NetBSD.org/src/rev/0acb1118aa8a
branches:  trunk
changeset: 320311:0acb1118aa8a
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sun Jul 01 07:18:56 2018 +0000

description:
Use a switch, we can (and will) optimize each case separately. No
functional change.

diffstat:

 sys/arch/x86/x86/fpu.c |  34 +++++++++++++++++++++++-----------
 1 files changed, 23 insertions(+), 11 deletions(-)

diffs (64 lines):

diff -r 66fb8294a6ab -r 0acb1118aa8a sys/arch/x86/x86/fpu.c
--- a/sys/arch/x86/x86/fpu.c    Sat Jun 30 22:47:51 2018 +0000
+++ b/sys/arch/x86/x86/fpu.c    Sun Jul 01 07:18:56 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fpu.c,v 1.44 2018/06/29 19:34:35 maxv Exp $    */
+/*     $NetBSD: fpu.c,v 1.45 2018/07/01 07:18:56 maxv Exp $    */
 
 /*
  * Copyright (c) 2008 The NetBSD Foundation, Inc.  All
@@ -96,7 +96,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: fpu.c,v 1.44 2018/06/29 19:34:35 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fpu.c,v 1.45 2018/07/01 07:18:56 maxv Exp $");
 
 #include "opt_multiprocessor.h"
 
@@ -661,24 +661,36 @@
        }
        KASSERT(pcb->pcb_fpcpu == NULL);
 
-       if (i386_use_fxsave) {
+       switch (x86_fpu_save) {
+       case FPU_SAVE_FSAVE:
+               memset(&fpu_save->sv_87, 0, x86_fpu_save_size);
+               fpu_save->sv_87.s87_tw = 0xffff;
+               fpu_save->sv_87.s87_cw = x87_cw;
+               break;
+       case FPU_SAVE_FXSAVE:
+               memset(&fpu_save->sv_xmm, 0, x86_fpu_save_size);
+               fpu_save->sv_xmm.fx_mxcsr = __INITIAL_MXCSR__;
+               fpu_save->sv_xmm.fx_mxcsr_mask = x86_fpu_mxcsr_mask;
+               fpu_save->sv_xmm.fx_cw = x87_cw;
+               break;
+       case FPU_SAVE_XSAVE:
+       case FPU_SAVE_XSAVEOPT:
                memset(&fpu_save->sv_xmm, 0, x86_fpu_save_size);
                fpu_save->sv_xmm.fx_mxcsr = __INITIAL_MXCSR__;
                fpu_save->sv_xmm.fx_mxcsr_mask = x86_fpu_mxcsr_mask;
                fpu_save->sv_xmm.fx_cw = x87_cw;
 
-               /* Force a reload of CW */
-               if ((x87_cw != __INITIAL_NPXCW__) &&
-                   (x86_fpu_save == FPU_SAVE_XSAVE ||
-                   x86_fpu_save == FPU_SAVE_XSAVEOPT)) {
+               /*
+                * Force a reload of CW if we're using the non-default
+                * value.
+                */
+               if (__predict_false(x87_cw != __INITIAL_NPXCW__)) {
                        fpu_save->sv_xsave_hdr.xsh_xstate_bv |=
                            XCR0_X87;
                }
-       } else {
-               memset(&fpu_save->sv_87, 0, x86_fpu_save_size);
-               fpu_save->sv_87.s87_tw = 0xffff;
-               fpu_save->sv_87.s87_cw = x87_cw;
+               break;
        }
+
        pcb->pcb_fpu_dflt_cw = x87_cw;
 
        if (x86_fpu_eager) {