[src/trunk]: src/lib/libc/arch/x86_64/gen PR/44293: Paul Goyette: Fix the mes...

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

details:   https://anonhg.NetBSD.org/src/rev/86b5565265d6
branches:  trunk
changeset: 770016:86b5565265d6
user:      christos <christos%NetBSD.org@localhost>
date:      Fri Sep 30 17:42:34 2011 +0000

description:
PR/44293: Paul Goyette: Fix the mess of the rounding code.

diffstat:

 lib/libc/arch/x86_64/gen/flt_rounds.S |  10 ++++++----
 lib/libc/arch/x86_64/gen/fpgetround.S |   9 ++++-----
 lib/libc/arch/x86_64/gen/fpsetround.S |  34 ++++++++++++++--------------------
 3 files changed, 24 insertions(+), 29 deletions(-)

diffs (102 lines):

diff -r c3c01b3149c7 -r 86b5565265d6 lib/libc/arch/x86_64/gen/flt_rounds.S
--- a/lib/libc/arch/x86_64/gen/flt_rounds.S     Fri Sep 30 15:47:20 2011 +0000
+++ b/lib/libc/arch/x86_64/gen/flt_rounds.S     Fri Sep 30 17:42:34 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: flt_rounds.S,v 1.5 2011/09/29 22:55:45 christos Exp $  */
+/*     $NetBSD: flt_rounds.S,v 1.6 2011/09/30 17:42:34 christos Exp $  */
 
 #include <machine/asm.h>
 
@@ -12,8 +12,10 @@
        _ALIGN_TEXT
 ENTRY(__flt_rounds)
        fnstcw  -4(%rsp)
-       movl    -4(%rsp), %eax
-       shrl    $10, %eax
+       movl    -4(%rsp), %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 c3c01b3149c7 -r 86b5565265d6 lib/libc/arch/x86_64/gen/fpgetround.S
--- a/lib/libc/arch/x86_64/gen/fpgetround.S     Fri Sep 30 15:47:20 2011 +0000
+++ b/lib/libc/arch/x86_64/gen/fpgetround.S     Fri Sep 30 17:42:34 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fpgetround.S,v 1.3 2002/06/12 19:17:22 fvdl Exp $      */
+/*     $NetBSD: fpgetround.S,v 1.4 2011/09/30 17:42:34 christos Exp $  */
 
 /*
  * Written by J.T. Conklin, Apr 4, 1995
@@ -8,7 +8,7 @@
 #include <machine/asm.h>
 
 /*
- * XXX store only x87 state. If an application only uses the fp*
+ * XXX load only x87 state. If an application only uses the fp*
  * interface, this should be in sync with the SSE mxcsr register.
  */
 
@@ -19,7 +19,6 @@
 ENTRY(fpgetround)
 #endif
        fnstcw -4(%rsp)
-       movl -4(%rsp),%eax
-       rorl $10,%eax
-       andl $3,%eax
+       movl -4(%rsp), %eax
+       andl $0x00000c00, %eax
        ret
diff -r c3c01b3149c7 -r 86b5565265d6 lib/libc/arch/x86_64/gen/fpsetround.S
--- a/lib/libc/arch/x86_64/gen/fpsetround.S     Fri Sep 30 15:47:20 2011 +0000
+++ b/lib/libc/arch/x86_64/gen/fpsetround.S     Fri Sep 30 17:42:34 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fpsetround.S,v 1.3 2002/06/12 19:17:22 fvdl Exp $      */
+/*     $NetBSD: fpsetround.S,v 1.4 2011/09/30 17:42:34 christos Exp $  */
 
 /*
  * Written by Frank van der Linden at Wasabi Systems for NetBSD.
@@ -21,28 +21,22 @@
 #else
 ENTRY(fpsetround)
 #endif
-       fnstcw  -4(%rsp)
-       stmxcsr -8(%rsp)
-
-       andl    $3,%edi
 
-       movl    -4(%rsp),%edx
-       rorl    $10,%edx
-       movl    %edx,%eax
-       andl    $3,%eax
+       fnstcw  -4(%rsp)
+       movl    -4(%rsp), %edx
+       movl    %edx, %eax
+       andl    $0x00000c00, %eax       
+       andl    $0xfffff3ff, %edx
+       orl     %edi, %edx
+       movl    %edx, -4(%rsp)
+       fldcw   -4(%rsp)
 
-       andl    $~3,%edx
+       stmxcsr -4(%rsp)
+       movl    -4(%rsp), %edx
+       andl    $0xffff9fff, %edx
+       sall    $3, %edi
        orl     %edi,%edx
-       roll    $10,%edx
        movl    %edx,-4(%rsp)
+       ldmxcsr -4(%rsp)
 
-       movl    -8(%rsp),%edx
-       rorl    $13,%edx
-       andl    $~3,%edx
-       orl     %edi,%edx
-       roll    $13,%edx
-       movl    %edx,-8(%rsp)
-
-       ldmxcsr -8(%rsp)
-       fldcw   -4(%rsp)
        ret