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authorRichard Henderson <rth@twiddle.net>2013-02-13 12:06:42 -0800
committerRichard Henderson <rth@twiddle.net>2013-03-06 07:47:24 -0800
commit5695fc848fb3cd25fb528dada44f8bbdd113c04a (patch)
treef36ec0917622006a45c7c24f488d9b429b0d1e54 /ports
parent79fd8731113e8402732190ff921aebaaef9218b0 (diff)
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arm: Add optimized ffs for armv6t2
Diffstat (limited to 'ports')
-rw-r--r--ports/ChangeLog.arm3
-rw-r--r--ports/sysdeps/arm/armv6t2/ffs.S35
-rw-r--r--ports/sysdeps/arm/armv6t2/ffsll.S50
3 files changed, 88 insertions, 0 deletions
diff --git a/ports/ChangeLog.arm b/ports/ChangeLog.arm
index 288dfb4c09..55e63fa368 100644
--- a/ports/ChangeLog.arm
+++ b/ports/ChangeLog.arm
@@ -1,5 +1,8 @@
2013-03-06 Richard Henderson <rth@redhat.com>
+ * sysdeps/arm/armv6t2/ffs.S: New file.
+ * sysdeps/arm/armv6t2/ffsll.S: New file.
+
* sysdeps/arm/sysdep.h (ARCH_HAS_HARD_TP): New macro.
(GET_TLS): Use hard-tp if ARCH_HAS_HARD_TP.
* sysdeps/unix/sysv/linux/arm/aeabi_read_tp.S: Likewise.
diff --git a/ports/sysdeps/arm/armv6t2/ffs.S b/ports/sysdeps/arm/armv6t2/ffs.S
new file mode 100644
index 0000000000..b2c88b9460
--- /dev/null
+++ b/ports/sysdeps/arm/armv6t2/ffs.S
@@ -0,0 +1,35 @@
+/* ffs -- find first set bit in an int, from least significant end.
+ Copyright (C) 2013 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ 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>
+
+ .syntax unified
+ .text
+
+ENTRY (__ffs)
+ cmp r0, #0
+ rbit r0, r0
+ itt ne
+ clzne r0, r0
+ addne r0, r0, #1
+ bx lr
+END (__ffs)
+
+weak_alias (__ffs, ffs)
+weak_alias (__ffs, ffsl)
+libc_hidden_builtin_def (ffs)
diff --git a/ports/sysdeps/arm/armv6t2/ffsll.S b/ports/sysdeps/arm/armv6t2/ffsll.S
new file mode 100644
index 0000000000..e49c70fdf1
--- /dev/null
+++ b/ports/sysdeps/arm/armv6t2/ffsll.S
@@ -0,0 +1,50 @@
+/* ffsll -- find first set bit in a long long, from least significant end.
+ Copyright (C) 2013 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ 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>
+
+ .syntax unified
+ .text
+
+ENTRY (ffsll)
+ @ If low part is 0, operate on the high part. Ensure that the
+ @ word on which we operate is in r0. Set r2 to the bit offset
+ @ of the word being considered. Set the flags for the word
+ @ being operated on.
+#ifdef __ARMEL__
+ cmp r0, #0
+ itee ne
+ movne r2, #0
+ moveq r2, #32
+ movseq r0, r1
+#else
+ cmp r1, #0
+ ittee ne
+ movne r2, #0
+ movne r0, r1
+ moveq r2, #32
+ cmpeq r0, #0
+#endif
+ @ Perform the ffs on r0.
+ rbit r0, r0
+ ittt ne
+ clzne r0, r0
+ addne r2, r2, #1
+ addne r0, r0, r2
+ bx lr
+END (ffsll)