1/* Vector optimized 32/64 bit S/390 version of stpncpy. 2 Copyright (C) 2015-2021 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library; if not, see 17 <https://www.gnu.org/licenses/>. */ 18 19#include <ifunc-stpncpy.h> 20 21#if HAVE_STPNCPY_Z13 22 23# include "sysdep.h" 24# include "asm-syntax.h" 25 26 .text 27 28/* char * stpncpy (char *dest, const char *src, size_t n) 29 Copies at most n characters of string src to dest 30 returning a pointer to its end or dest+n 31 if src is smaller than n. 32 33 Register usage: 34 -%r0 = return value 35 -%r1 = zero byte index 36 -%r2 = curr dst pointer 37 -%r3 = curr src pointer 38 -%r4 = n 39 -%r5 = current_len 40 -%r6 = loaded bytes 41 -%r7 = border, tmp 42*/ 43ENTRY(STPNCPY_Z13) 44 .machine "z13" 45 .machinemode "zarch_nohighgprs" 46 47# if !defined __s390x__ 48 llgfr %r4,%r4 49# endif /* !defined __s390x__ */ 50 51 clgfi %r4,0 52 ber %r14 /* Nothing to do, if n == 0. */ 53 54 la %r0,0(%r4,%r2) /* Save destination pointer + n for return. */ 55 vlvgp %v31,%r6,%r7 /* Save registers. */ 56 57 vlbb %v16,0(%r3),6 /* Load s until next 4k-byte boundary. */ 58 lcbb %r6,0(%r3),6 /* Get bytes to 4k-byte boundary or 16. */ 59 llgfr %r6,%r6 /* Convert 32bit to 64bit. */ 60 61 lghi %r5,0 /* current_len = 0. */ 62 63 clgrjle %r4,%r6,.Lremaining_v16 /* If n <= loaded-bytes 64 -> process remaining. */ 65 66 /* n > loaded-byte-count */ 67 vfenezb %v17,%v16,%v16 /* Find element not equal with zero search. */ 68 vlgvb %r1,%v17,7 /* Load zero index or 16 if not found. */ 69 clrjl %r1,%r6,.Lfound_v16_store /* Found zero within loaded bytes, 70 copy and return. */ 71 72 /* Align s to 16 byte. */ 73 risbgn %r7,%r3,60,128+63,0 /* %r3 = bits 60-63 of %r2 'and' 15. */ 74 lghi %r5,15 /* current_len = 15. */ 75 slr %r5,%r7 /* Compute highest index to 16byte boundary. */ 76 77 /* Zero not found and n > loaded-byte-count. */ 78 vstl %v16,%r5,0(%r2) /* Copy loaded characters - no zero. */ 79 ahi %r5,1 /* Start loop at next character. */ 80 81 /* Now we are 16byte aligned, so we can load a full vreg 82 without page fault. */ 83 lgr %r1,%r5 /* If %r5 + 64 < maxlen? -> loop64. */ 84 aghi %r1,64 85 clgrjl %r1,%r4,.Lloop64 86 87 vl %v16,0(%r5,%r3) /* Load s. */ 88 clgijl %r4,17,.Lremaining_v16 /* If n <= 16, process remaining 89 bytes. */ 90.Llt64: 91 lgr %r7,%r4 92 slgfi %r7,16 /* border_len = n - 16. */ 93 94 clgrjhe %r5,%r7,.Lremaining_v16 /* If current_len >= border 95 then process remaining bytes. */ 96 vfenezbs %v17,%v16,%v16 /* Find element not equal with zero search. */ 97 je .Lfound_v16 /* Jump away if zero was found. */ 98 vl %v18,16(%r5,%r3) /* Load next part of s. */ 99 vst %v16,0(%r5,%r2) /* Save previous part without zero to dst. */ 100 aghi %r5,16 101 102 clgrjhe %r5,%r7,.Lremaining_v18 103 vfenezbs %v17,%v18,%v18 104 je .Lfound_v18 105 vl %v16,16(%r5,%r3) 106 vst %v18,0(%r5,%r2) 107 aghi %r5,16 108 109 clgrjhe %r5,%r7,.Lremaining_v16 110 vfenezbs %v17,%v16,%v16 111 je .Lfound_v16 112 vl %v18,16(%r5,%r3) 113 vst %v16,0(%r5,%r2) 114 aghi %r5,16 115 116.Lremaining_v18: 117 vlr %v16,%v18 118.Lremaining_v16: 119 /* v16 contains the remaining bytes [1...16]. 120 Store remaining bytes and append string-termination. */ 121 vfenezb %v17,%v16,%v16 /* Find element not equal with zero search. */ 122 slgrk %r7,%r4,%r5 /* Remaining bytes = maxlen - current_len */ 123 aghi %r7,-1 /* vstl needs highest index. */ 124 la %r2,0(%r5,%r2) /* vstl has no index register. */ 125 vlgvb %r1,%v17,7 /* Load zero index or 16 if not found. */ 126 /* Zero in remaining bytes? -> jump away (zero-index <= max-index). */ 127 clrjle %r1,%r7,.Lfound_v16_store 128 vstl %v16,%r7,0(%r2) /* Store remaining bytes without null 129 termination! */ 130.Lend: 131 /* Restore saved registers. */ 132 vlgvg %r6,%v31,0 133 vlgvg %r7,%v31,1 134 lgr %r2,%r0 /* Load saved dest-ptr. */ 135 br %r14 136 137.Lfound_v16_32: 138 aghi %r5,32 139 j .Lfound_v16 140.Lfound_v18_48: 141 aghi %r5,32 142.Lfound_v18_16: 143 aghi %r5,16 144.Lfound_v18: 145 vlr %v16,%v18 146.Lfound_v16: 147 /* v16 contains a zero. Store remaining bytes to zero. current_len 148 has not reached border, thus checking for n is not needed! */ 149 vlgvb %r1,%v17,7 /* Load byte index of zero. */ 150 la %r2,0(%r5,%r2) /* vstl has no support for index-register. */ 151.Lfound_v16_store: 152 vstl %v16,%r1,0(%r2) /* Copy characters including zero. */ 153 /* Fill remaining bytes with zero - remaining count always > 0. */ 154 algr %r5,%r1 /* Remaining bytes (=%r4) = ... */ 155 slgr %r4,%r5 /* = maxlen - (currlen + zero_index + 1) */ 156 la %r2,0(%r1,%r2) /* Pointer to zero. start filling beyond. */ 157 lgr %r0,%r2 /* Save return-pointer to found zero. */ 158 clgije %r4,1,.Lend /* Skip zero-filling, if found zero is last 159 possible character. 160 (1 is substracted from r4 below!). */ 161 aghi %r4,-2 /* mvc with exrl needs count - 1. 162 (additional -1, see remaining bytes above) */ 163 srlg %r6,%r4,8 /* Split into 256 byte blocks. */ 164 ltgr %r6,%r6 165 je .Lzero_lt256 166.Lzero_loop256: 167 mvc 1(256,%r2),0(%r2) /* Fill 256 zeros at once. */ 168 la %r2,256(%r2) 169 brctg %r6,.Lzero_loop256 /* Loop until all blocks are processed. */ 170.Lzero_lt256: 171 exrl %r4,.Lmvc_lt256 172 j .Lend 173.Lmvc_lt256: 174 mvc 1(1,%r2),0(%r2) 175 176.Lloop64: 177 vl %v16,0(%r5,%r3) 178 vfenezbs %v17,%v16,%v16 /* Find element not equal with zero search. */ 179 je .Lfound_v16 /* Jump away if zero was found. */ 180 vl %v18,16(%r5,%r3) /* Load next part of s. */ 181 vst %v16,0(%r5,%r2) /* Save previous part without zero to dst. */ 182 vfenezbs %v17,%v18,%v18 183 je .Lfound_v18_16 184 vl %v16,32(%r5,%r3) 185 vst %v18,16(%r5,%r2) 186 vfenezbs %v17,%v16,%v16 187 je .Lfound_v16_32 188 vl %v18,48(%r5,%r3) 189 vst %v16,32(%r5,%r2) 190 vfenezbs %v17,%v18,%v18 191 je .Lfound_v18_48 192 vst %v18,48(%r5,%r2) 193 194 aghi %r5,64 195 lgr %r1,%r5 /* If %r5 + 64 < maxlen? -> loop64. */ 196 aghi %r1,64 197 clgrjl %r1,%r4,.Lloop64 198 199 vl %v16,0(%r5,%r3) /* Load s. */ 200 j .Llt64 201END(STPNCPY_Z13) 202 203# if ! HAVE_STPNCPY_IFUNC 204strong_alias (STPNCPY_Z13, __stpncpy) 205weak_alias (__stpncpy, stpncpy) 206# endif 207 208# if ! HAVE_STPNCPY_C && defined SHARED && IS_IN (libc) 209strong_alias (STPNCPY_Z13, __GI___stpncpy) 210# endif 211#endif 212