367b8112fe
Move all header files for xtensa to arch/xtensa/include and platform and variant header files to the appropriate arch/xtensa/platforms/ and arch/xtensa/variants/ directories. Moving the files gets also rid of all uses of symlinks in the Makefile. This has been completed already for the majority of the architectures and xtensa is one out of six missing. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Chris Zankel <chris@zankel.net>
148 lines
3.8 KiB
ArmAsm
148 lines
3.8 KiB
ArmAsm
/*
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* arch/xtensa/lib/strnlen_user.S
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*
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* This file is subject to the terms and conditions of the GNU General
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* Public License. See the file "COPYING" in the main directory of
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* this archive for more details.
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*
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* Returns strnlen, including trailing zero terminator.
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* Zero indicates error.
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*
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* Copyright (C) 2002 Tensilica Inc.
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*/
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#include <variant/core.h>
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/* Load or store instructions that may cause exceptions use the EX macro. */
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#define EX(insn,reg1,reg2,offset,handler) \
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9: insn reg1, reg2, offset; \
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.section __ex_table, "a"; \
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.word 9b, handler; \
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.previous
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/*
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* size_t __strnlen_user(const char *s, size_t len)
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*/
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#ifdef __XTENSA_EB__
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# define MASK0 0xff000000
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# define MASK1 0x00ff0000
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# define MASK2 0x0000ff00
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# define MASK3 0x000000ff
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#else
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# define MASK0 0x000000ff
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# define MASK1 0x0000ff00
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# define MASK2 0x00ff0000
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# define MASK3 0xff000000
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#endif
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# Register use:
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# a2/ src
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# a3/ len
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# a4/ tmp
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# a5/ mask0
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# a6/ mask1
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# a7/ mask2
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# a8/ mask3
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# a9/ tmp
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# a10/ tmp
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.text
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.align 4
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.global __strnlen_user
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.type __strnlen_user,@function
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__strnlen_user:
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entry sp, 16 # minimal stack frame
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# a2/ s, a3/ len
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addi a4, a2, -4 # because we overincrement at the end;
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# we compensate with load offsets of 4
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movi a5, MASK0 # mask for byte 0
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movi a6, MASK1 # mask for byte 1
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movi a7, MASK2 # mask for byte 2
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movi a8, MASK3 # mask for byte 3
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bbsi.l a2, 0, .L1mod2 # if only 8-bit aligned
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bbsi.l a2, 1, .L2mod4 # if only 16-bit aligned
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/*
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* String is word-aligned.
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*/
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.Laligned:
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srli a10, a3, 2 # number of loop iterations with 4B per loop
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#if XCHAL_HAVE_LOOPS
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loopnez a10, .Ldone
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#else
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beqz a10, .Ldone
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slli a10, a10, 2
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add a10, a10, a4 # a10 = end of last 4B chunk
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#endif /* XCHAL_HAVE_LOOPS */
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.Loop:
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EX(l32i, a9, a4, 4, lenfixup) # get next word of string
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addi a4, a4, 4 # advance string pointer
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bnone a9, a5, .Lz0 # if byte 0 is zero
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bnone a9, a6, .Lz1 # if byte 1 is zero
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bnone a9, a7, .Lz2 # if byte 2 is zero
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bnone a9, a8, .Lz3 # if byte 3 is zero
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#if !XCHAL_HAVE_LOOPS
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blt a4, a10, .Loop
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#endif
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.Ldone:
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EX(l32i, a9, a4, 4, lenfixup) # load 4 bytes for remaining checks
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bbci.l a3, 1, .L100
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# check two more bytes (bytes 0, 1 of word)
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addi a4, a4, 2 # advance string pointer
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bnone a9, a5, .Lz0 # if byte 0 is zero
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bnone a9, a6, .Lz1 # if byte 1 is zero
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.L100:
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bbci.l a3, 0, .L101
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# check one more byte (byte 2 of word)
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# Actually, we don't need to check. Zero or nonzero, we'll add one.
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# Do not add an extra one for the NULL terminator since we have
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# exhausted the original len parameter.
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addi a4, a4, 1 # advance string pointer
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.L101:
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sub a2, a4, a2 # compute length
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retw
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# NOTE that in several places below, we point to the byte just after
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# the zero byte in order to include the NULL terminator in the count.
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.Lz3: # byte 3 is zero
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addi a4, a4, 3 # point to zero byte
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.Lz0: # byte 0 is zero
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addi a4, a4, 1 # point just beyond zero byte
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sub a2, a4, a2 # subtract to get length
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retw
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.Lz1: # byte 1 is zero
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addi a4, a4, 1+1 # point just beyond zero byte
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sub a2, a4, a2 # subtract to get length
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retw
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.Lz2: # byte 2 is zero
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addi a4, a4, 2+1 # point just beyond zero byte
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sub a2, a4, a2 # subtract to get length
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retw
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.L1mod2: # address is odd
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EX(l8ui, a9, a4, 4, lenfixup) # get byte 0
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addi a4, a4, 1 # advance string pointer
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beqz a9, .Lz3 # if byte 0 is zero
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bbci.l a4, 1, .Laligned # if string pointer is now word-aligned
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.L2mod4: # address is 2 mod 4
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addi a4, a4, 2 # advance ptr for aligned access
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EX(l32i, a9, a4, 0, lenfixup) # get word with first two bytes of string
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bnone a9, a7, .Lz2 # if byte 2 (of word, not string) is zero
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bany a9, a8, .Laligned # if byte 3 (of word, not string) is nonzero
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# byte 3 is zero
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addi a4, a4, 3+1 # point just beyond zero byte
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sub a2, a4, a2 # subtract to get length
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retw
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.section .fixup, "ax"
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.align 4
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lenfixup:
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movi a2, 0
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retw
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