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/* Vector optimized 32/64 bit S/390 version of strncat.
Copyright (C) 2015-2024 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
<https://www.gnu.org/licenses/>. */
#include <ifunc-strncat.h>
#if HAVE_STRNCAT_Z13
# include "sysdep.h"
# include "asm-syntax.h"
.text
/* char * strncat (const char *dest, const char *src, size_t n)
Concatenate two strings - at most n characters of src.
Register usage:
-r0=saved dest pointer for return
-r1=tmp
-r2=dest
-r3=src
-r4=n
-r5=current_len
-r6=tmp
-r7=tmp
-v16=part of src
-v17=index of zero
-v18=part of src
-v31=register save area for r6, r7
*/
ENTRY(STRNCAT_Z13)
.machine "z13"
.machinemode "zarch_nohighgprs"
# if !defined __s390x__
llgfr %r4,%r4
# endif /* !defined __s390x__ */
clgfi %r4,0
ber %r14 /* Nothing to do, if n == 0. */
lgr %r0,%r2 /* Save destination pointer for return. */
vlvgp %v31,%r6,%r7 /* Save registers. */
/* STRLEN
%r1 = loaded bytes (tmp)
%r6 = zero byte index (tmp)
%r2 = dst
*/
vlbb %v16,0(%r2),6 /* Load s until next 4k-byte boundary. */
lcbb %r1,0(%r2),6 /* Get bytes to 4k-byte boundary or 16. */
vfenezb %v16,%v16,%v16 /* Find element not equal with zero search. */
vlgvb %r5,%v16,7 /* Load zero index or 16 if not found. */
clrjl %r5,%r1,.Llen_end /* Found zero within loaded bytes, end. */
/* Align s to 16 byte. */
risbgn %r1,%r2,60,128+63,0 /* %r3 = bits 60-63 of %r2 'and' 15. */
lghi %r5,16 /* current_len = 16. */
slr %r5,%r1 /* Compute bytes to 16bytes boundary. */
/* Find zero in 16byte aligned loop. */
.Llen_loop:
vl %v16,0(%r5,%r2) /* Load s. */
vfenezbs %v16,%v16,%v16 /* Find element not equal with zero search. */
je .Llen_found /* Jump away if zero was found. */
vl %v16,16(%r5,%r2)
vfenezbs %v16,%v16,%v16
je .Llen_found16
vl %v16,32(%r5,%r2)
vfenezbs %v16,%v16,%v16
je .Llen_found32
vl %v16,48(%r5,%r2)
vfenezbs %v16,%v16,%v16
je .Llen_found48
aghi %r5,64
j .Llen_loop /* No zero -> loop. */
.Llen_found48:
aghi %r5,16
.Llen_found32:
aghi %r5,16
.Llen_found16:
aghi %r5,16
.Llen_found:
vlgvb %r1,%v16,7 /* Load byte index of zero. */
algr %r5,%r1
.Llen_end:
/* STRCPY
%r1 = zero byte index (tmp)
%r6 = loaded bytes (tmp)
%r3 = curr src pointer
%r2 = curr dst pointer
%r7 = border, tmp
*/
la %r2,0(%r5,%r2) /* strcpy at end of dst-string. */
vlbb %v16,0(%r3),6 /* Load s until next 4k-byte boundary. */
lcbb %r6,0(%r3),6 /* Get bytes to 4k-byte boundary or 16. */
llgfr %r6,%r6 /* Convert 32bit to 64bit. */
lghi %r5,0 /* current_len = 0. */
clgrjle %r4,%r6,.Lcpy_remaining_v16 /* If n <= loaded-bytes
-> process remaining. */
/* n > loaded-byte-count. */
vfenezb %v17,%v16,%v16 /* Find element not equal with zero search. */
vlgvb %r1,%v17,7 /* Load zero index or 16 if not found. */
clrjl %r1,%r6,.Lcpy_found_v16_store /* Found zero within loaded
bytes, copy and return. */
/* Align s to 16 byte. */
risbgn %r7,%r3,60,128+63,0 /* %r3 = bits 60-63 of %r2 'and' 15. */
lghi %r5,15 /* current_len = 15. */
slr %r5,%r7 /* Compute highest index to 16byte boundary. */
/* Zero not found and n > loaded-byte-count. */
vstl %v16,%r5,0(%r2) /* Copy loaded characters - no zero. */
ahi %r5,1 /* Start loop at next character. */
/*
Now we are 16byte aligned, so we can load a full vreg
without page fault.
*/
lgr %r1,%r5 /* If %r5 + 64 < maxlen? -> loop64. */
aghi %r1,64
clgrjl %r1,%r4,.Lcpy_loop64
vl %v16,0(%r5,%r3) /* Load s. */
clgijl %r4,17,.Lcpy_remaining_v16 /* If n <=16,
process remaining bytes. */
.Lcpy_lt64:
lgr %r7,%r4
slgfi %r7,16 /* border_len = n - 16. */
/* If current_len >= border then process remaining bytes. */
clgrjhe %r5,%r7,.Lcpy_remaining_v16
vfenezbs %v17,%v16,%v16 /* Find element not equal with zero search. */
je .Lcpy_found_v16 /* Jump away if zero was found. */
vl %v18,16(%r5,%r3) /* Load next part of s. */
vst %v16,0(%r5,%r2) /* Store previous part without zero to dst. */
aghi %r5,16
clgrjhe %r5,%r7,.Lcpy_remaining_v18
vfenezbs %v17,%v18,%v18
je .Lcpy_found_v18
vl %v16,16(%r5,%r3)
vst %v18,0(%r5,%r2)
aghi %r5,16
clgrjhe %r5,%r7,.Lcpy_remaining_v16
vfenezbs %v17,%v16,%v16
je .Lcpy_found_v16
vl %v18,16(%r5,%r3)
vst %v16,0(%r5,%r2)
aghi %r5,16
.Lcpy_remaining_v18:
vlr %v16,%v18
.Lcpy_remaining_v16:
/* v16 contains the remaining bytes [1...16].
Store remaining bytes and append string-termination. */
vfenezb %v17,%v16,%v16 /* Find element not equal with zero search. */
slgrk %r7,%r4,%r5 /* Remaining bytes = maxlen - current_len. */
aghi %r7,-1 /* vstl needs highest index. */
vlgvb %r1,%v17,7 /* Load zero index or 16 if not found. */
la %r2,0(%r5,%r2) /* vstl has no index register. */
/* Zero-index within remaining-bytes, store up to zero and end. */
clgrjle %r1,%r7,.Lcpy_found_v16_store
vstl %v16,%r7,0(%r2) /* Store remaining bytes. */
lghi %r1,0
stc %r1,1(%r7,%r2) /* Store string-null-termination beyond n. */
.Lcpy_end:
/* Restore saved registers. */
vlgvg %r6,%v31,0
vlgvg %r7,%v31,1
lgr %r2,%r0 /* Load saved dest-ptr. */
br %r14
.Lcpy_found_v16_32:
aghi %r5,32
j .Lcpy_found_v16
.Lcpy_found_v18_48:
aghi %r5,32
.Lcpy_found_v18_16:
aghi %r5,16
.Lcpy_found_v18:
vlr %v16,%v18
.Lcpy_found_v16:
/* v16 contains a zero. Store remaining bytes to zero. current_len
has not reached border, thus checking for n is not needed! */
vlgvb %r1,%v17,7 /* Load byte index of zero. */
la %r2,0(%r5,%r2)
.Lcpy_found_v16_store:
vstl %v16,%r1,0(%r2) /* Copy characters including zero. */
j .Lcpy_end
/* Find zero in 16byte aligned loop. */
.Lcpy_loop64:
vl %v16,0(%r5,%r3) /* Load s. */
vfenezbs %v17,%v16,%v16 /* Find element not equal with zero search. */
je .Lcpy_found_v16 /* Jump away if zero was found. */
vl %v18,16(%r5,%r3) /* Load next part of s. */
vst %v16,0(%r5,%r2) /* Store previous part without zero to dst. */
vfenezbs %v17,%v18,%v18
je .Lcpy_found_v18_16
vl %v16,32(%r5,%r3)
vst %v18,16(%r5,%r2)
vfenezbs %v17,%v16,%v16
je .Lcpy_found_v16_32
vl %v18,48(%r5,%r3)
vst %v16,32(%r5,%r2)
vfenezbs %v17,%v18,%v18
je .Lcpy_found_v18_48
vst %v18,48(%r5,%r2)
aghi %r5,64
lgr %r1,%r5 /* If %r5 + 64 < maxlen? -> loop64. */
aghi %r1,64
clgrjl %r1,%r4,.Lcpy_loop64
vl %v16,0(%r5,%r3) /* Load s. */
j .Lcpy_lt64
END(STRNCAT_Z13)
# if ! HAVE_STRNCAT_IFUNC
strong_alias (STRNCAT_Z13, strncat)
# endif
# if ! HAVE_STRNCAT_C
/* See string/strncat.c and define STRNCAT_PRIMARY. */
strong_alias (STRNCAT_Z13, __strncat)
# if defined SHARED && IS_IN (libc)
strong_alias (__strncat, __GI___strncat)
# endif
# endif
#endif
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