powerpc: round/roundf refactor

This patches consolidates all the powerpc round{f} implementations on
the generic sysdeps/powerpc/fpu/s_round{f}.  The generic implementation
uses either the compiler builts for ISA 2.03+ (which generates the
frim instruction) or a generic implementation which uses FP only
operations.

The IFUNC organization for powerpc64 is also change to be enabled only
for powerpc64 and not for powerpc64le (since minium ISA of 2.08 does not
require the fallback generic implementation).

Checked on powerpc-linux-gnu (built without --with-cpu, with
--with-cpu=power4 and with --with-cpu=power5+ and --disable-multi-arch),
powerpc64-linux-gnu (built without --with-cp and with --with-cpu=power5+
and --disable-multi-arch).

	* sysdeps/powerpc/fpu/round_to_integer.h (set_fenv_mode): Add
	ROUND handling.
	(round_mode): Add definition for ROUND.
	(round_to_integer_float): Likewise.
	* sysdeps/powerpc/fpu/s_round.c: New file.
	* sysdeps/powerpc/fpu/s_roundf.c: New file.
	* sysdeps/powerpc/powerpc32/fpu/s_round.S: Remove file.
	* sysdeps/powerpc/powerpc32/fpu/s_roundf.S: Likewise.
	* sysdep/powerpc/powepc32/power4/fpu/multiarch/s_round-power5+.S:
	Likewise.
	* sysdep/powerpc/powepc32/power4/fpu/multiarch/s_round-ppc32.S:
	Likewise.
	* sysdep/powerpc/powepc32/power4/fpu/multiarch/s_roundf-power5+.S:
	Likewise.
	* sysdep/powerpc/powepc32/power4/fpu/multiarch/s_roundf-ppc32.S:
	Likewise.
	* sysdep/powerpc/powepc32/power4/fpu/multiarch/s_round-power5+.c: New
	file.
	* sysdep/powerpc/powepc32/power4/fpu/multiarch/s_round-ppc32.c:
	Likewise.
	* sysdep/powerpc/powepc32/power4/fpu/multiarch/s_roundf-power5+.c:
	Likewise.
	* sysdep/powerpc/powepc32/power4/fpu/multiarch/s_roundf-ppc32.c:
	Likewise.
	* sysdep/powerpc/powerpc32/power5+/fpu/s_round.S: Remove file.
	* sysdep/powerpc/powerpc32/power5+/fpu/s_roundf.S: Likewise.
	* sysdep/powerpc/powerpc64/be/fpu/multiarch/Makefile
	(libm-sysdep_routines): Add s_round-power5+, s_round-ppc64,
	s_roundf-power5+, and s_roundf-ppc64.
	(CFLAGS-s_round-power5+.c, CFLAGS-s_roundf-power5+.c): New rule.
	* sysdep/powerpc/powercp64/be/fpu/multiarch/s_round-power5+.c: New
	file.
	* sysdep/powerpc/powercp64/be/fpu/multiarch/s_round-ppc64.c: Likewise.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_round.c: Move to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_round.c: ... here.
	* sysdep/powerpc/powercp64/be/fpu/multiarch/s_roundf-power5+.c: New
	file.
	* sysdep/powerpc/powercp64/be/fpu/multiarch/s_roundf-ppc64.c:
	Likewise.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_roundf.c: Move to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_roundf.c: ... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
	(libm-sysdep_routines): Remove s_round-power5+, s_round-ppc64,
	s_roundf-power5+, and s_roundf-ppc64.
	* sysdep/powerpc/powerpc64/fpu/multiarch/s_round-power5+.S: Remove
	file.
	* sysdep/powerpc/powerpc64/fpu/multiarch/s_round-ppc64.S: Likewise.
	* sysdep/powerpc/powerpc64/fpu/multiarch/s_roundf-power5+.S:
	Likewise.
	* sysdep/powerpc/powerpc64/fpu/multiarch/s_roundf-ppc64.S: Likewise.
	* sysdeps/powerpc/powerpc64/fpu/s_round.S: Likewise.
	* sysdeps/powerpc/powerpc64/fpu/s_roundf.S: Likewise.
	* sysdep/powerpc/powerpc64/power5+/fpu/s_round.S: Likewise.
	* sysdep/powerpc/powerpc64/power5+/fpu/s_roundf.S: Likewise.

Reviewed-by: Gabriel F. T. Gomes <gabriel@inconstante.eti.br>

1 files changed, 19 insertions, 1 deletions

diff --git a/sysdeps/powerpc/fpu/round_to_integer.h b/sysdeps/powerpc/fpu/round_to_integer.h
index ff77dde394..b318e37190 100644
--- a/sysdeps/powerpc/fpu/round_to_integer.h
+++ b/sysdeps/powerpc/fpu/round_to_integer.h
@@ -24,7 +24,8 @@
 enum round_mode
 {
   CEIL,
-  FLOOR
+  FLOOR,
+  ROUND
 };
 
 static inline void
@@ -35,6 +36,7 @@ set_fenv_mode (enum round_mode mode)
   {
   case CEIL:  rmode = FE_UPWARD; break;
   case FLOOR: rmode = FE_DOWNWARD; break;
+  case ROUND: rmode = FE_TOWARDZERO; break;
   default:    rmode = FE_TONEAREST; break;
   }
   __fesetround_inline_nocheck (rmode);
@@ -57,12 +59,24 @@ round_to_integer_float (enum round_mode mode, float x)
   set_fenv_mode (mode);
   if (x > 0.0)
     {
+      /* IEEE 1003.1 round function.  IEEE specifies "round to the nearest
+	 integer value, rounding halfway cases away from zero, regardless of
+	 the current rounding mode."  However PowerPC Architecture defines
+	 "Round to Nearest" as "Choose the best approximation. In case of a
+	 tie, choose the one that is even (least significant bit o).".
+	 So we can't use the PowerPC "Round to Nearest" mode. Instead we set
+	 "Round toward Zero" mode and round by adding +-0.5 before rounding
+	 to the integer value.  */
+      if (mode == ROUND)
+	r += 0.5f;
       r += 0x1p+23;
       r -= 0x1p+23;
       r = fabs (r);
     }
   else if (x < 0.0)
     {
+      if (mode == ROUND)
+	r -= 0.5f;
       r -= 0x1p+23;
       r += 0x1p+23;
       r = -fabs (r);
@@ -89,12 +103,16 @@ round_to_integer_double (enum round_mode mode, double x)
   set_fenv_mode (mode);
   if (x > 0.0)
     {
+      if (mode == ROUND)
+	r += 0.5;
       r += 0x1p+52;
       r -= 0x1p+52;
       r = fabs (r);
     }
   else if (x < 0.0)
     {
+      if (mode == ROUND)
+	r -= 0.5;
       r -= 0x1p+52;
       r += 0x1p+52;
       r = -fabs (r);