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authorMike Frysinger <vapier@gentoo.org>2008-01-05 10:05:27 +0000
committerMike Frysinger <vapier@gentoo.org>2008-01-05 10:05:27 +0000
commit124ec188720b6bdea85ade49e7ea195161b12fce (patch)
tree2bce39bc1e51bd587e010a61419b47d122be3165 /libc/string/xtensa/strncpy.S
parent9c95d5d28d8d40f7b826c9399f5ce781bbc61567 (diff)
Chris Zankel writes:
The following patches add support for the Xtensa processor architecture to uClibc. They are based on a recent SVN checkout (12/05/2007). The first patch (attached to this post) adds Xtensa support to various shared configuration and make files. The following patches then include the Xtensa specific files and directories. I welcome any feedback and would appreciate it if you could include the patches into the mainline tree. I am certainly committed to maintain the port. Bob Wilson was kind enough to review the patches. Some notes about the architecture: Xtensa is a configurable and extensible processor architecture developed by Tensilica. For more information, please visit: www.linux-xtensa.org.
Diffstat (limited to 'libc/string/xtensa/strncpy.S')
-rw-r--r--libc/string/xtensa/strncpy.S241
1 files changed, 241 insertions, 0 deletions
diff --git a/libc/string/xtensa/strncpy.S b/libc/string/xtensa/strncpy.S
new file mode 100644
index 000000000..7ba2ef77d
--- /dev/null
+++ b/libc/string/xtensa/strncpy.S
@@ -0,0 +1,241 @@
+/* Optimized strcpy for Xtensa.
+ Copyright (C) 2001, 2007 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, write to the Free
+ Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
+ Boston, MA 02110-1301, USA. */
+
+#include "../../sysdeps/linux/xtensa/sysdep.h"
+#include <bits/xtensa-config.h>
+
+#ifdef __XTENSA_EB__
+#define MASK0 0xff000000
+#define MASK1 0x00ff0000
+#define MASK2 0x0000ff00
+#define MASK3 0x000000ff
+#else
+#define MASK0 0x000000ff
+#define MASK1 0x0000ff00
+#define MASK2 0x00ff0000
+#define MASK3 0xff000000
+#endif
+
+/* Do not use .literal_position in the ENTRY macro. */
+#undef LITERAL_POSITION
+#define LITERAL_POSITION
+
+ .text
+ .align 4
+ .literal_position
+__strncpy_aux:
+
+.Lsrc1mod2: // src address is odd
+ l8ui a8, a3, 0 // get byte 0
+ addi a3, a3, 1 // advance src pointer
+ s8i a8, a10, 0 // store byte 0
+ addi a4, a4, -1 // decrement n
+ beqz a4, .Lret // if n is zero
+ addi a10, a10, 1 // advance dst pointer
+ beqz a8, .Lfill // if byte 0 is zero
+ bbci.l a3, 1, .Lsrcaligned // if src is now word-aligned
+
+.Lsrc2mod4: // src address is 2 mod 4
+ l8ui a8, a3, 0 // get byte 0
+ addi a4, a4, -1 // decrement n
+ s8i a8, a10, 0 // store byte 0
+ beqz a4, .Lret // if n is zero
+ addi a10, a10, 1 // advance dst pointer
+ beqz a8, .Lfill // if byte 0 is zero
+ l8ui a8, a3, 1 // get byte 0
+ addi a3, a3, 2 // advance src pointer
+ s8i a8, a10, 0 // store byte 0
+ addi a4, a4, -1 // decrement n
+ beqz a4, .Lret // if n is zero
+ addi a10, a10, 1 // advance dst pointer
+ bnez a8, .Lsrcaligned
+ j .Lfill
+
+.Lret:
+ retw
+
+
+ENTRY (strncpy)
+ /* a2 = dst, a3 = src */
+
+ mov a10, a2 // leave dst in return value register
+ beqz a4, .Lret // if n is zero
+
+ movi a11, MASK0
+ movi a5, MASK1
+ movi a6, MASK2
+ movi a7, MASK3
+ bbsi.l a3, 0, .Lsrc1mod2
+ bbsi.l a3, 1, .Lsrc2mod4
+.Lsrcaligned:
+
+ /* Check if the destination is aligned. */
+ movi a8, 3
+ bnone a10, a8, .Laligned
+
+ j .Ldstunaligned
+
+
+/* Fill the dst with zeros -- n is at least 1. */
+
+.Lfill:
+ movi a9, 0
+ bbsi.l a10, 0, .Lfill1mod2
+ bbsi.l a10, 1, .Lfill2mod4
+.Lfillaligned:
+ blti a4, 4, .Lfillcleanup
+
+ /* Loop filling complete words with zero. */
+#if XCHAL_HAVE_LOOPS
+
+ srai a8, a4, 2
+ loop a8, 1f
+ s32i a9, a10, 0
+ addi a10, a10, 4
+
+1: slli a8, a8, 2
+ sub a4, a4, a8
+
+#else /* !XCHAL_HAVE_LOOPS */
+
+1: s32i a9, a10, 0
+ addi a10, a10, 4
+ addi a4, a4, -4
+ bgei a4, 4, 1b
+
+#endif /* !XCHAL_HAVE_LOOPS */
+
+ beqz a4, 2f
+
+.Lfillcleanup:
+ /* Fill leftover (1 to 3) bytes with zero. */
+ s8i a9, a10, 0 // store byte 0
+ addi a4, a4, -1 // decrement n
+ addi a10, a10, 1
+ bnez a4, .Lfillcleanup
+
+2: retw
+
+.Lfill1mod2: // dst address is odd
+ s8i a9, a10, 0 // store byte 0
+ addi a4, a4, -1 // decrement n
+ beqz a4, 2b // if n is zero
+ addi a10, a10, 1 // advance dst pointer
+ bbci.l a10, 1, .Lfillaligned // if dst is now word-aligned
+
+.Lfill2mod4: // dst address is 2 mod 4
+ s8i a9, a10, 0 // store byte 0
+ addi a4, a4, -1 // decrement n
+ beqz a4, 2b // if n is zero
+ s8i a9, a10, 1 // store byte 1
+ addi a4, a4, -1 // decrement n
+ beqz a4, 2b // if n is zero
+ addi a10, a10, 2 // advance dst pointer
+ j .Lfillaligned
+
+
+/* dst is word-aligned; src is word-aligned; n is at least 1. */
+
+ .align 4
+ /* (2 mod 4) alignment for loop instruction */
+.Laligned:
+#if XCHAL_HAVE_LOOPS
+ _movi.n a8, 0 // set up for the maximum loop count
+ loop a8, 1f // loop forever (almost anyway)
+ blti a4, 5, .Ldstunaligned // n is near limit; do one at a time
+ l32i a8, a3, 0 // get word from src
+ addi a3, a3, 4 // advance src pointer
+ bnone a8, a11, .Lz0 // if byte 0 is zero
+ bnone a8, a5, .Lz1 // if byte 1 is zero
+ bnone a8, a6, .Lz2 // if byte 2 is zero
+ s32i a8, a10, 0 // store word to dst
+ addi a4, a4, -4 // decrement n
+ addi a10, a10, 4 // advance dst pointer
+ bnone a8, a7, .Lfill // if byte 3 is zero
+1:
+
+#else /* !XCHAL_HAVE_LOOPS */
+
+1: blti a4, 5, .Ldstunaligned // n is near limit; do one at a time
+ l32i a8, a3, 0 // get word from src
+ addi a3, a3, 4 // advance src pointer
+ bnone a8, a11, .Lz0 // if byte 0 is zero
+ bnone a8, a5, .Lz1 // if byte 1 is zero
+ bnone a8, a6, .Lz2 // if byte 2 is zero
+ s32i a8, a10, 0 // store word to dst
+ addi a4, a4, -4 // decrement n
+ addi a10, a10, 4 // advance dst pointer
+ bany a8, a7, 1b // no zeroes
+#endif /* !XCHAL_HAVE_LOOPS */
+
+ j .Lfill
+
+.Lz0: /* Byte 0 is zero. */
+#ifdef __XTENSA_EB__
+ movi a8, 0
+#endif
+ s8i a8, a10, 0
+ addi a4, a4, -1 // decrement n
+ addi a10, a10, 1 // advance dst pointer
+ j .Lfill
+
+.Lz1: /* Byte 1 is zero. */
+#ifdef __XTENSA_EB__
+ extui a8, a8, 16, 16
+#endif
+ s16i a8, a10, 0
+ addi a4, a4, -2 // decrement n
+ addi a10, a10, 2 // advance dst pointer
+ j .Lfill
+
+.Lz2: /* Byte 2 is zero. */
+#ifdef __XTENSA_EB__
+ extui a8, a8, 16, 16
+#endif
+ s16i a8, a10, 0
+ movi a8, 0
+ s8i a8, a10, 2
+ addi a4, a4, -3 // decrement n
+ addi a10, a10, 3 // advance dst pointer
+ j .Lfill
+
+ .align 4
+ /* (2 mod 4) alignment for loop instruction */
+.Ldstunaligned:
+
+#if XCHAL_HAVE_LOOPS
+ _movi.n a8, 0 // set up for the maximum loop count
+ loop a8, 2f // loop forever (almost anyway)
+#endif
+1: l8ui a8, a3, 0
+ addi a3, a3, 1
+ s8i a8, a10, 0
+ addi a4, a4, -1
+ beqz a4, 3f
+ addi a10, a10, 1
+#if XCHAL_HAVE_LOOPS
+ beqz a8, 2f
+#else
+ bnez a8, 1b
+#endif
+2: j .Lfill
+
+3: retw
+
+libc_hidden_def (strncpy)