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+/* Vector optimized 32/64 bit S/390 version of wcpncpy.
+ Copyright (C) 2015-2016 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/>. */
+
+#if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
+
+# include "sysdep.h"
+# include "asm-syntax.h"
+
+ .text
+
+/* wchar_t * wcpncpy (wchar_t *dest, const wchar_t *src, size_t n)
+ Copies at most n characters of string src to dest
+ returning a pointer to its end or dest+n
+ if src is smaller than n.
+
+ Register usage:
+ -%r0 = return value
+ -%r1 = zero byte index
+ -%r2 = curr dst pointer
+ -%r3 = curr src pointer
+ -%r4 = n
+ -%r5 = current_len
+ -%r6 = loaded bytes
+ -%r7 = border, tmp
+*/
+ENTRY(__wcpncpy_vx)
+ .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. */
+
+ vlbb %v16,0(%r3),6 /* Load s until next 4k-byte boundary. */
+
+ tmll %r3,3 /* Test if s is 4-byte aligned? */
+ jne .Lfallback /* And use common-code variant if not. */
+
+ vlvgp %v31,%r6,%r7 /* Save registers. */
+ lghi %r5,0 /* current_len = 0. */
+
+ lcbb %r6,0(%r3),6 /* Get bytes to 4k-byte boundary or 16. */
+ llgfr %r6,%r6 /* Convert 32bit to 64bit. */
+
+ /* Check range of maxlen and convert to byte-count. */
+# ifdef __s390x__
+ tmhh %r4,49152 /* Test bit 0 or 1 of maxlen. */
+ lghi %r1,-4 /* Max byte-count is 18446744073709551612. */
+# else
+ tmlh %r4,49152 /* Test bit 0 or 1 of maxlen. */
+ llilf %r1,4294967292 /* Max byte-count is 4294967292. */
+# endif /* !__s390x__ */
+ sllg %r4,%r4,2 /* Convert character-count to byte-count. */
+ locgrne %r4,%r1 /* Use max byte-count, if bit 0/1 was one. */
+
+ la %r0,0(%r4,%r2) /* Save destination pointer + n for return. */
+
+ clgrjle %r4,%r6,.Lremaining_v16 /* If n <= loaded-bytes
+ -> process remaining. */
+
+ /* n > loaded-byte-count */
+ vfenezf %v17,%v16,%v16 /* Find element not equal with zero search. */
+ vlgvb %r1,%v17,7 /* Load zero index or 16 if not found. */
+ aghi %r1,3 /* Also copy remaining bytes of zero. */
+ clrjl %r1,%r6,.Lfound_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,.Lloop64
+
+ vl %v16,0(%r5,%r3) /* Load s. */
+ clgijl %r4,17,.Lremaining_v16 /* If n <=16,
+ process remaining bytes. */
+.Llt64:
+ lgr %r7,%r4
+ slgfi %r7,16 /* border_len = n - 16. */
+
+ clgrjhe %r5,%r7,.Lremaining_v16 /* If current_len >= border
+ then process remaining bytes. */
+ vfenezfs %v17,%v16,%v16 /* Find element not equal with zero search. */
+ je .Lfound_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,.Lremaining_v18
+ vfenezfs %v17,%v18,%v18
+ je .Lfound_v18
+ vl %v16,16(%r5,%r3)
+ vst %v18,0(%r5,%r2)
+ aghi %r5,16
+
+ clgrjhe %r5,%r7,.Lremaining_v16
+ vfenezfs %v17,%v16,%v16
+ je .Lfound_v16
+ vl %v18,16(%r5,%r3)
+ vst %v16,0(%r5,%r2)
+ aghi %r5,16
+
+.Lremaining_v18:
+ vlr %v16,%v18
+.Lremaining_v16:
+ /* v16 contains the remaining bytes [1...16].
+ Store remaining bytes and append string-termination. */
+ vfenezf %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. */
+ la %r2,0(%r5,%r2) /* vstl has no index register. */
+ vlgvb %r1,%v17,7 /* Load zero index or 16 if not found. */
+ aghi %r1,3 /* Also copy remaining bytes of zero. */
+ /* Zero in remaining bytes? -> jump away (zero-index <= max-index). */
+ clrjle %r1,%r7,.Lfound_v16_store
+ vstl %v16,%r7,0(%r2) /* Store remaining bytes without null
+ termination! */
+.Lend:
+ /* Restore saved registers. */
+ vlgvg %r6,%v31,0
+ vlgvg %r7,%v31,1
+ lgr %r2,%r0 /* Load saved dest-ptr. */
+ br %r14
+
+.Lfound_v16_32:
+ aghi %r5,32
+ j .Lfound_v16
+.Lfound_v18_48:
+ aghi %r5,32
+.Lfound_v18_16:
+ aghi %r5,16
+.Lfound_v18:
+ vlr %v16,%v18
+.Lfound_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) /* vstl has no support for index-register. */
+ aghi %r1,3 /* Also copy remaining bytes of zero. */
+.Lfound_v16_store:
+ vstl %v16,%r1,0(%r2) /* Copy characters including zero. */
+ /* Fill remaining bytes with zero - remaining byte count always > 0. */
+ algr %r5,%r1 /* Remaining bytes (=%r4) = ... */
+ slgr %r4,%r5 /* = n - (currlen + zero_index + 1) */
+ la %r2,0(%r1,%r2) /* Pointer to zero. start filling beyond. */
+ lay %r0,-3(%r2) /* Save return-pointer to found zero. */
+ clgije %r4,1,.Lend /* Skip zero-filling, if found-zero is last
+ possible character.
+ (1 is substracted from r4 below!). */
+ aghi %r4,-2 /* mvc with exrl needs count - 1.
+ (additional -1, see remaining bytes above) */
+ srlg %r6,%r4,8 /* Split into 256 byte blocks. */
+ ltgr %r6,%r6
+ je .Lzero_lt256
+.Lzero_loop256:
+ mvc 1(256,%r2),0(%r2) /* Fill 256 zeros at once. */
+ la %r2,256(%r2)
+ brctg %r6,.Lzero_loop256 /* Loop until all blocks are processed. */
+.Lzero_lt256:
+ exrl %r4,.Lmvc_lt256
+ j .Lend
+.Lmvc_lt256:
+ mvc 1(1,%r2),0(%r2)
+
+ /* Find zero in 16byte aligned loop. */
+.Lloop64:
+ vl %v16,0(%r5,%r3)
+ vfenezfs %v17,%v16,%v16 /* Find element not equal with zero search. */
+ je .Lfound_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. */
+ vfenezfs %v17,%v18,%v18
+ je .Lfound_v18_16
+ vl %v16,32(%r5,%r3)
+ vst %v18,16(%r5,%r2)
+ vfenezfs %v17,%v16,%v16
+ je .Lfound_v16_32
+ vl %v18,48(%r5,%r3)
+ vst %v16,32(%r5,%r2)
+ vfenezfs %v17,%v18,%v18
+ je .Lfound_v18_48
+ vst %v18,48(%r5,%r2)
+
+ aghi %r5,64
+ lgr %r1,%r5 /* If %r5 + 64 < maxlen? -> loop64. */
+ aghi %r1,64
+ clgrjl %r1,%r4,.Lloop64
+
+ vl %v16,0(%r5,%r3) /* Load s. */
+ j .Llt64
+
+.Lfallback:
+ jg __wcpncpy_c
+END(__wcpncpy_vx)
+#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */