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authorDavid S. Miller <davem@davemloft.net>2012-02-27 20:36:30 -0800
committerDavid S. Miller <davem@davemloft.net>2012-02-27 20:36:30 -0800
commit1aff59a3f78e2eea23c5303cede967613bd13bfc (patch)
tree62e7b41ba1d53078cab0fbe80746af5a8726af71 /sysdeps/sparc/sparc64/fpu/s_floorf.S
parentd6b5aa5879729713ffd27d38307e373bf60b0049 (diff)
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Optimized sparc floor{,f} routines.
	* sysdeps/sparc/sparc32/sparcv9/fpu/s_floor.S: New file.
	* sysdeps/sparc/sparc32/sparcv9/fpu/s_floorf.S: New file.
	* sysdeps/sparc/sparc64/fpu/s_floor.S: New file.
	* sysdeps/sparc/sparc64/fpu/s_floorf.S: New file.
Diffstat (limited to 'sysdeps/sparc/sparc64/fpu/s_floorf.S')
-rw-r--r--sysdeps/sparc/sparc64/fpu/s_floorf.S81
1 files changed, 81 insertions, 0 deletions
diff --git a/sysdeps/sparc/sparc64/fpu/s_floorf.S b/sysdeps/sparc/sparc64/fpu/s_floorf.S
new file mode 100644
index 0000000000..711cbe4d1e
--- /dev/null
+++ b/sysdeps/sparc/sparc64/fpu/s_floorf.S
@@ -0,0 +1,81 @@
+/* Float floor function, sparc64 version.
+   Copyright (C) 2012 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by David S. Miller <davem@davemloft.net>, 2012.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+	/* Since changing the rounding mode is extremely expensive, we
+	   try to round up using a method that is rounding mode
+	   agnostic.
+
+	   We add then subtract (or subtract than add if the initial
+	   value was negative) 2**23 to the value, then subtract it
+	   back out.
+
+	   This will clear out the fractional portion of the value.
+	   One of two things will happen for non-whole initial values.
+	   Either the rounding mode will round it up, or it will be
+	   rounded down.  If the value started out whole, it will be
+	   equal after the addition and subtraction.  This means we
+	   can accurately detect with one test whether we need to add
+	   another 1.0 to round it up properly.
+
+	   We pop constants into the FPU registers using the incoming
+	   argument stack slots, since this avoid having to use any
+	   PIC references.  We also thus avoid having to allocate a
+	   register window.
+
+	   VIS instructions are used to facilitate the formation of
+	   easier constants, and the propagation of the sign bit.  */
+
+#define TWO_TWENTYTHREE	0x4b000000		/* 2**23 */
+#define ONE_DOT_ZERO	0x3f800000		/* 1.0 */
+
+#define ZERO		%f10			/* 0.0 */
+#define SIGN_BIT	%f12			/* -0.0 */
+
+ENTRY (__floorf)
+	sethi	%hi(TWO_TWENTYTHREE), %o2
+	sethi	%hi(ONE_DOT_ZERO), %o3
+	fzeros	ZERO
+
+	fnegs	ZERO, SIGN_BIT
+
+	st	%o2, [%sp + STACK_BIAS + 128]
+	fabss	%f1, %f14
+
+	ld	[%sp + STACK_BIAS + 128], %f16
+	fcmps	%fcc3, %f14, %f16
+
+	fmovsuge %fcc3, ZERO, %f16
+	fands	%f1, SIGN_BIT, SIGN_BIT
+
+	fors	%f16, SIGN_BIT, %f16
+	fadds	%f1, %f16, %f5
+	fsubs	%f5, %f16, %f5
+	fcmps	%fcc2, %f5, %f1
+	st	%o3, [%sp + STACK_BIAS + 128]
+
+	ld	[%sp + STACK_BIAS + 128], %f9
+	fmovsule %fcc2, ZERO, %f9
+	fsubs	%f5, %f9, %f0
+	fabss	%f0, %f0
+	retl
+	 fors	%f0, SIGN_BIT, %f0
+END (__floorf)
+weak_alias (__floorf, floorf)