[src/trunk]: src/lib/libc/arch/i386/gen make rounding work

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

details:   https://anonhg.NetBSD.org/src/rev/26f50a34a554
branches:  trunk
changeset: 770026:26f50a34a554
user:      christos <christos%NetBSD.org@localhost>
date:      Fri Sep 30 23:42:00 2011 +0000

description:
make rounding work

diffstat:

 lib/libc/arch/i386/gen/flt_rounds.S |  10 ++++++----
 lib/libc/arch/i386/gen/fpgetround.S |  15 ++++++++-------
 lib/libc/arch/i386/gen/fpsetround.S |  35 +++++++++++++++++------------------
 3 files changed, 31 insertions(+), 29 deletions(-)

diffs (111 lines):

diff -r 12224e240681 -r 26f50a34a554 lib/libc/arch/i386/gen/flt_rounds.S
--- a/lib/libc/arch/i386/gen/flt_rounds.S       Fri Sep 30 22:17:50 2011 +0000
+++ b/lib/libc/arch/i386/gen/flt_rounds.S       Fri Sep 30 23:42:00 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: flt_rounds.S,v 1.8 2011/09/29 22:53:13 christos Exp $  */
+/*     $NetBSD: flt_rounds.S,v 1.9 2011/09/30 23:42:00 christos Exp $  */
 
 #include <machine/asm.h>
 
@@ -12,8 +12,10 @@
        _ALIGN_TEXT
 ENTRY(__flt_rounds)
        fnstcw  -4(%esp)
-       movl    -4(%esp), %eax
-       shrl    $10, %eax
+       movl    -4(%esp), %ecx
+       shrl    $9, %ecx
+       andl    $6, %ecx
+       movl    $0x2d, %eax     /* 0x2d = 00.10.11.01 */
+       sarl    %cl, %eax       /* 0,1,2,3 -> 1,3,2,0 */
        andl    $3, %eax
-       xorl    $1, %eax        /* map 0,1,2,3 -> 1,0,3,2 */
        ret
diff -r 12224e240681 -r 26f50a34a554 lib/libc/arch/i386/gen/fpgetround.S
--- a/lib/libc/arch/i386/gen/fpgetround.S       Fri Sep 30 22:17:50 2011 +0000
+++ b/lib/libc/arch/i386/gen/fpgetround.S       Fri Sep 30 23:42:00 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fpgetround.S,v 1.5 2002/01/13 21:45:43 thorpej Exp $   */
+/*     $NetBSD: fpgetround.S,v 1.6 2011/09/30 23:42:00 christos Exp $  */
 
 /*
  * Written by J.T. Conklin, Apr 4, 1995
@@ -7,16 +7,17 @@
 
 #include <machine/asm.h>
 
+/*
+ * XXX load only x87 state.
+ */
+
 #ifdef WEAK_ALIAS
 WEAK_ALIAS(fpgetround, _fpgetround)
 ENTRY(_fpgetround)
 #else
 ENTRY(fpgetround)
 #endif
-       subl $4,%esp
-       fnstcw (%esp)
-       movl (%esp),%eax
-       rorl $10,%eax
-       andl $3,%eax
-       addl $4,%esp
+       fnstcw -4(%esp)
+       movl -4(%esp), %eax
+       andl $0x00000c00, %eax
        ret
diff -r 12224e240681 -r 26f50a34a554 lib/libc/arch/i386/gen/fpsetround.S
--- a/lib/libc/arch/i386/gen/fpsetround.S       Fri Sep 30 22:17:50 2011 +0000
+++ b/lib/libc/arch/i386/gen/fpsetround.S       Fri Sep 30 23:42:00 2011 +0000
@@ -1,34 +1,33 @@
-/*     $NetBSD: fpsetround.S,v 1.3 2002/01/13 21:45:43 thorpej Exp $   */
+/*     $NetBSD: fpsetround.S,v 1.4 2011/09/30 23:42:00 christos Exp $  */
 
 /*
- * Written by Charles M. Hannum, Apr 9, 1995
+ * Written by Frank van der Linden at Wasabi Systems for NetBSD.
  * Public domain.
  */
 
 #include <machine/asm.h>
 
+/*
+ * XXX set both the x87 control word
+ * Applications should only set exception and round flags
+ */ 
+
+
 #ifdef WEAK_ALIAS
 WEAK_ALIAS(fpsetround, _fpsetround)
 ENTRY(_fpsetround)
 #else
 ENTRY(fpsetround)
 #endif
-       subl $4,%esp
-
-       fnstcw (%esp)
-       movl (%esp),%eax
-
-       rorl $10,%eax
-       movl %eax,%edx
-       andl $3,%eax
 
-       subl %eax,%edx
-       movl 8(%esp),%ecx
-       andl $3,%ecx
-       orl %ecx,%edx
-       roll $10,%edx
-       movl %edx,(%esp)
-       fldcw (%esp)
+       fnstcw  -4(%esp)
+       movl    -4(%esp), %edx
+       movl    %edx, %eax
+       andl    $0x00000c00, %eax       
+       andl    $0xfffff3ff, %edx
+       movl    4(%esp), %edi
+       orl     %edi, %edx
+       movl    %edx, -4(%esp)
+       fldcw   -4(%esp)
 
-       addl $4,%esp
        ret