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208 lines
6.4 KiB
ArmAsm
208 lines
6.4 KiB
ArmAsm
/* Vector optimized 32/64 bit S/390 version of strncpy.
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Copyright (C) 2015-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
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# include "sysdep.h"
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# include "asm-syntax.h"
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.text
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/* char * strncpy (const char *dest, const char *src, size_t n)
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Copy at most n characters of string src to dest.
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Register usage:
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-r0=dest pointer for return
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-r1=tmp, zero byte index
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-r2=dest
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-r3=src
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-r4=n
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-r5=current_len
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-r6=tmp, loaded bytes
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-r7=tmp, border
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-v16=part of src
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-v17=index of zero
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-v18=part of src
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-v31=register save area for r6, r7
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*/
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ENTRY(__strncpy_vx)
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.machine "z13"
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.machinemode "zarch_nohighgprs"
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# if !defined __s390x__
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llgfr %r4,%r4
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# endif /* !defined __s390x__ */
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clgfi %r4,0
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ber %r14 /* Nothing to do, if n == 0. */
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lgr %r0,%r2 /* Save destination pointer for return. */
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vlvgp %v31,%r6,%r7 /* Save registers. */
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vlbb %v16,0(%r3),6 /* Load s until next 4k-byte boundary. */
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lcbb %r6,0(%r3),6 /* Get bytes to 4k-byte boundary or 16. */
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llgfr %r6,%r6 /* Convert 32bit to 64bit. */
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lghi %r5,0 /* current_len = 0. */
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clgrjle %r4,%r6,.Lremaining_v16 /* If n <= loaded-bytes
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-> process remaining. */
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/* n > loaded-byte-count. */
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vfenezb %v17,%v16,%v16 /* Find element not equal with zero search. */
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vlgvb %r1,%v17,7 /* Load zero index or 16 if not found. */
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clrjl %r1,%r6,.Lfound_v16_store /* Found zero within loaded bytes,
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copy and return. */
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/* Align s to 16 byte. */
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risbgn %r7,%r3,60,128+63,0 /* %r3 = bits 60-63 of %r2 'and' 15. */
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lghi %r5,15 /* current_len = 15. */
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slr %r5,%r7 /* Compute highest index to 16byte boundary. */
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/* Zero not found and n > loaded-byte-count. */
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vstl %v16,%r5,0(%r2) /* Copy loaded characters - no zero. */
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ahi %r5,1 /* Start loop at next character. */
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/* Now we are 16byte aligned, so we can load
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a full vreg without page fault. */
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lgr %r1,%r5 /* If %r5 + 64 < maxlen? -> loop64. */
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aghi %r1,64
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clgrjl %r1,%r4,.Lloop64
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vl %v16,0(%r5,%r3) /* Load s. */
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clgijl %r4,17,.Lremaining_v16 /* If n <= 16, process remaining
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bytes. */
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.Llt64:
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lgr %r7,%r4
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slgfi %r7,16 /* border_len = n - 16. */
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clgrjhe %r5,%r7,.Lremaining_v16 /* If current_len >= border
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then process remaining bytes. */
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vfenezbs %v17,%v16,%v16 /* Find element not equal with zero search. */
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je .Lfound_v16 /* Jump away if zero was found. */
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vl %v18,16(%r5,%r3) /* Load next part of s. */
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vst %v16,0(%r5,%r2) /* Store previous part without zero to dst. */
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aghi %r5,16
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clgrjhe %r5,%r7,.Lremaining_v18
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vfenezbs %v17,%v18,%v18
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je .Lfound_v18
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vl %v16,16(%r5,%r3)
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vst %v18,0(%r5,%r2)
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aghi %r5,16
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clgrjhe %r5,%r7,.Lremaining_v16
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vfenezbs %v17,%v16,%v16
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je .Lfound_v16
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vl %v18,16(%r5,%r3)
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vst %v16,0(%r5,%r2)
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aghi %r5,16
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.Lremaining_v18:
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vlr %v16,%v18
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.Lremaining_v16:
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/* v16 contains the remaining bytes [1...16].
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Store remaining bytes and append string-termination. */
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vfenezb %v17,%v16,%v16 /* Find element not equal with zero search. */
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slgrk %r7,%r4,%r5 /* Remaining bytes = maxlen - current_len. */
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aghi %r7,-1 /* vstl needs highest index. */
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la %r2,0(%r5,%r2) /* vstl has no index register. */
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vlgvb %r1,%v17,7 /* Load zero index or 16 if not found. */
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/* Zero in remaining bytes? -> jump away (zero-index < max-index)
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Do not jump away if zero-index == max-index,
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but simply copy zero with vstl below. */
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clrjl %r1,%r7,.Lfound_v16_store
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vstl %v16,%r7,0(%r2) /* Store remaining bytes without null
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termination!. */
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.Lend:
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/* Restore saved registers. */
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vlgvg %r6,%v31,0
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vlgvg %r7,%v31,1
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lgr %r2,%r0 /* Load saved dest-ptr. */
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br %r14
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.Lfound_v16_32:
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aghi %r5,32
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j .Lfound_v16
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.Lfound_v18_48:
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aghi %r5,32
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.Lfound_v18_16:
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aghi %r5,16
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.Lfound_v18:
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vlr %v16,%v18
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.Lfound_v16:
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/* v16 contains a zero. Store remaining bytes to zero. current_len
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has not reached border, thus checking for n is not needed! */
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vlgvb %r1,%v17,7 /* Load byte index of zero. */
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la %r2,0(%r5,%r2) /* vstl has no support for index-register. */
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.Lfound_v16_store:
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vstl %v16,%r1,0(%r2) /* Copy characters including zero. */
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/* Fill remaining bytes with zero - remaining count always > 0. */
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algr %r5,%r1 /* Remaining bytes (=%r4) = ... */
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slgr %r4,%r5 /* = n - (current_len + zero_index + 1). */
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la %r2,0(%r1,%r2) /* Pointer to zero. start filling beyond. */
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aghi %r4,-2 /* mvc with exrl needs count - 1.
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(additional -1, see remaining bytes above) */
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srlg %r6,%r4,8 /* Split into 256 byte blocks. */
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ltgr %r6,%r6
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je .Lzero_lt256
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.Lzero_loop256:
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mvc 1(256,%r2),0(%r2) /* Fill 256 zeros at once. */
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la %r2,256(%r2)
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brctg %r6,.Lzero_loop256 /* Loop until all blocks are processed. */
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.Lzero_lt256:
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exrl %r4,.Lmvc_lt256
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j .Lend
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.Lmvc_lt256:
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mvc 1(1,%r2),0(%r2)
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.Lloop64:
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vl %v16,0(%r5,%r3) /* Load s. */
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vfenezbs %v17,%v16,%v16 /* Find element not equal with zero search. */
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je .Lfound_v16 /* Jump away if zero was found. */
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vl %v18,16(%r5,%r3) /* Load next part of s. */
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vst %v16,0(%r5,%r2) /* Store previous part without zero to dst. */
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vfenezbs %v17,%v18,%v18
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je .Lfound_v18_16
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vl %v16,32(%r5,%r3)
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vst %v18,16(%r5,%r2)
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vfenezbs %v17,%v16,%v16
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je .Lfound_v16_32
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vl %v18,48(%r5,%r3)
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vst %v16,32(%r5,%r2)
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vfenezbs %v17,%v18,%v18
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je .Lfound_v18_48
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vst %v18,48(%r5,%r2)
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aghi %r5,64
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lgr %r1,%r5 /* If %r5 + 64 < maxlen? -> loop64. */
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aghi %r1,64
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clgrjl %r1,%r4,.Lloop64
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vl %v16,0(%r5,%r3) /* Load s. */
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j .Llt64
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END(__strncpy_vx)
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# define strncpy __strncpy_c
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# undef libc_hidden_builtin_def
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# define libc_hidden_builtin_def(name) strong_alias(__strncpy_c, __GI_strncpy)
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#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
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/* Include strncpy-implementation in s390-32/s390-64 subdirectory. */
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#include <strncpy.S>
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