2020-11-12 16:12:24 +00:00
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/* Optimized strncpy implementation for POWER9 LE.
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2022-01-01 18:54:23 +00:00
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Copyright (C) 2020-2022 Free Software Foundation, Inc.
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2020-11-12 16:12:24 +00:00
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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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<https://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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2020-11-12 16:12:24 +00:00
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#ifdef USE_AS_STPNCPY
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# ifndef STPNCPY
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# define FUNC_NAME __stpncpy
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# else
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# define FUNC_NAME STPNCPY
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# endif
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#else
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2020-11-12 16:12:24 +00:00
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# ifndef STRNCPY
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# define FUNC_NAME strncpy
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# else
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# define FUNC_NAME STRNCPY
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# endif
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2020-11-12 16:12:24 +00:00
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#endif /* !USE_AS_STPNCPY */
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2020-11-12 16:12:24 +00:00
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#ifndef MEMSET
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/* For builds without IFUNC support, local calls should be made to internal
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GLIBC symbol (created by libc_hidden_builtin_def). */
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# ifdef SHARED
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# define MEMSET_is_local
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# define MEMSET __GI_memset
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# else
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# define MEMSET memset
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# endif
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#endif
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#define FRAMESIZE (FRAME_MIN_SIZE+8)
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/* Implements the function
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char * [r3] strncpy (char *dest [r3], const char *src [r4], size_t n [r5])
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2020-11-12 16:12:24 +00:00
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or
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char * [r3] stpncpy (char *dest [r3], const char *src [r4], size_t n [r5])
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if USE_AS_STPNCPY is defined.
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2020-11-12 16:12:24 +00:00
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The implementation can load bytes past a null terminator, but only
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up to the next 16-byte aligned address, so it never crosses a page. */
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.machine power9
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#ifdef MEMSET_is_local
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ENTRY_TOCLESS (FUNC_NAME, 4)
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#else
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ENTRY (FUNC_NAME, 4)
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#endif
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CALL_MCOUNT 2
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/* NULL string optimizations */
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cmpdi r5, 0
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beqlr
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lbz r0,0(r4)
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stb r0,0(r3)
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addi r11,r3,1
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addi r5,r5,-1
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vspltisb v18,0 /* Zeroes in v18 */
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cmpdi r0,0
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beq L(zero_padding)
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/* Empty/1-byte string optimization */
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cmpdi r5,0
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2020-11-12 16:12:24 +00:00
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#ifdef USE_AS_STPNCPY
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bgt L(cont)
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/* Compute pointer to last byte copied into dest. */
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addi r3,r3,1
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blr
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L(cont):
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#else
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2020-11-12 16:12:24 +00:00
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beqlr
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2020-11-12 16:12:24 +00:00
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#endif
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2020-11-12 16:12:24 +00:00
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addi r4,r4,1
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neg r7,r4
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rldicl r9,r7,0,60 /* How many bytes to get source 16B aligned? */
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/* Get source 16B aligned */
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lvx v0,0,r4
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lvsr v1,0,r4
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vperm v0,v18,v0,v1
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vcmpequb v6,v0,v18 /* 0xff if byte is NULL, 0x00 otherwise */
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vctzlsbb r7,v6 /* Number of trailing zeroes */
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addi r8,r7,1 /* Add null terminator */
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/* r8 = bytes including null
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r9 = bytes to get source 16B aligned
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if r8 > r9
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no null, copy r9 bytes
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else
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there is a null, copy r8 bytes and return. */
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cmpld r8,r9
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bgt L(no_null)
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cmpld cr6,r8,r5 /* r8 <= n? */
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ble cr6,L(null)
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sldi r10,r5,56 /* stxvl wants size in top 8 bits */
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stxvl 32+v0,r11,r10 /* Partial store */
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2020-11-12 16:12:24 +00:00
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#ifdef USE_AS_STPNCPY
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/* Compute pointer to last byte copied into dest. */
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add r3,r11,r5
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#endif
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2020-11-12 16:12:24 +00:00
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blr
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L(null):
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sldi r10,r8,56 /* stxvl wants size in top 8 bits */
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stxvl 32+v0,r11,r10 /* Partial store */
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2020-11-12 16:12:24 +00:00
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#ifdef USE_AS_STPNCPY
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/* Compute pointer to last byte copied into dest. */
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add r3,r11,r7
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#endif
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2020-11-12 16:12:24 +00:00
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add r11,r11,r8
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sub r5,r5,r8
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b L(zero_padding)
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L(no_null):
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cmpld r9,r5 /* Check if length was reached. */
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bge L(n_tail1)
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sldi r10,r9,56 /* stxvl wants size in top 8 bits */
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stxvl 32+v0,r11,r10 /* Partial store */
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add r4,r4,r9
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add r11,r11,r9
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sub r5,r5,r9
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L(loop):
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cmpldi cr6,r5,64 /* Check if length was reached. */
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ble cr6,L(final_loop)
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lxv 32+v0,0(r4)
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vcmpequb. v6,v0,v18 /* Any zero bytes? */
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bne cr6,L(prep_tail1)
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lxv 32+v1,16(r4)
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vcmpequb. v6,v1,v18 /* Any zero bytes? */
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bne cr6,L(prep_tail2)
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lxv 32+v2,32(r4)
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vcmpequb. v6,v2,v18 /* Any zero bytes? */
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bne cr6,L(prep_tail3)
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lxv 32+v3,48(r4)
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vcmpequb. v6,v3,v18 /* Any zero bytes? */
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bne cr6,L(prep_tail4)
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stxv 32+v0,0(r11)
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stxv 32+v1,16(r11)
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stxv 32+v2,32(r11)
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stxv 32+v3,48(r11)
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addi r4,r4,64
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addi r11,r11,64
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addi r5,r5,-64
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b L(loop)
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L(final_loop):
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cmpldi cr5,r5,16
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lxv 32+v0,0(r4)
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vcmpequb. v6,v0,v18 /* Any zero bytes? */
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ble cr5,L(prep_n_tail1)
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bne cr6,L(count_tail1)
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addi r5,r5,-16
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cmpldi cr5,r5,16
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lxv 32+v1,16(r4)
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vcmpequb. v6,v1,v18 /* Any zero bytes? */
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ble cr5,L(prep_n_tail2)
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bne cr6,L(count_tail2)
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addi r5,r5,-16
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cmpldi cr5,r5,16
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lxv 32+v2,32(r4)
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vcmpequb. v6,v2,v18 /* Any zero bytes? */
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ble cr5,L(prep_n_tail3)
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bne cr6,L(count_tail3)
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addi r5,r5,-16
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lxv 32+v3,48(r4)
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vcmpequb. v6,v3,v18 /* Any zero bytes? */
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beq cr6,L(n_tail4)
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vctzlsbb r8,v6 /* Number of trailing zeroes */
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cmpld r8,r5 /* r8 < n? */
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blt L(tail4)
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L(n_tail4):
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stxv 32+v0,0(r11)
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stxv 32+v1,16(r11)
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stxv 32+v2,32(r11)
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sldi r10,r5,56 /* stxvl wants size in top 8 bits */
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addi r11,r11,48 /* Offset */
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stxvl 32+v3,r11,r10 /* Partial store */
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2020-11-12 16:12:24 +00:00
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#ifdef USE_AS_STPNCPY
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/* Compute pointer to last byte copied into dest. */
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add r3,r11,r5
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#endif
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2020-11-12 16:12:24 +00:00
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blr
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L(prep_n_tail1):
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beq cr6,L(n_tail1) /* Any zero bytes? */
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vctzlsbb r8,v6 /* Number of trailing zeroes */
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cmpld r8,r5 /* r8 < n? */
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blt L(tail1)
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L(n_tail1):
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sldi r10,r5,56 /* stxvl wants size in top 8 bits */
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stxvl 32+v0,r11,r10 /* Partial store */
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2020-11-12 16:12:24 +00:00
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#ifdef USE_AS_STPNCPY
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/* Compute pointer to last byte copied into dest. */
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add r3,r11,r5
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#endif
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2020-11-12 16:12:24 +00:00
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blr
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L(prep_n_tail2):
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beq cr6,L(n_tail2) /* Any zero bytes? */
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vctzlsbb r8,v6 /* Number of trailing zeroes */
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cmpld r8,r5 /* r8 < n? */
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blt L(tail2)
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L(n_tail2):
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stxv 32+v0,0(r11)
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sldi r10,r5,56 /* stxvl wants size in top 8 bits */
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addi r11,r11,16 /* offset */
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stxvl 32+v1,r11,r10 /* Partial store */
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2020-11-12 16:12:24 +00:00
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#ifdef USE_AS_STPNCPY
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/* Compute pointer to last byte copied into dest. */
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add r3,r11,r5
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#endif
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2020-11-12 16:12:24 +00:00
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blr
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L(prep_n_tail3):
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beq cr6,L(n_tail3) /* Any zero bytes? */
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vctzlsbb r8,v6 /* Number of trailing zeroes */
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cmpld r8,r5 /* r8 < n? */
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blt L(tail3)
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L(n_tail3):
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stxv 32+v0,0(r11)
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stxv 32+v1,16(r11)
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sldi r10,r5,56 /* stxvl wants size in top 8 bits */
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addi r11,r11,32 /* Offset */
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stxvl 32+v2,r11,r10 /* Partial store */
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2020-11-12 16:12:24 +00:00
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#ifdef USE_AS_STPNCPY
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/* Compute pointer to last byte copied into dest. */
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add r3,r11,r5
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#endif
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2020-11-12 16:12:24 +00:00
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blr
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L(prep_tail1):
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L(count_tail1):
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vctzlsbb r8,v6 /* Number of trailing zeroes */
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L(tail1):
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addi r9,r8,1 /* Add null terminator */
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sldi r10,r9,56 /* stxvl wants size in top 8 bits */
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stxvl 32+v0,r11,r10 /* Partial store */
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2020-11-12 16:12:24 +00:00
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#ifdef USE_AS_STPNCPY
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/* Compute pointer to last byte copied into dest. */
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add r3,r11,r8
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#endif
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2020-11-12 16:12:24 +00:00
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add r11,r11,r9
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sub r5,r5,r9
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b L(zero_padding)
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L(prep_tail2):
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addi r5,r5,-16
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L(count_tail2):
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vctzlsbb r8,v6 /* Number of trailing zeroes */
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L(tail2):
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addi r9,r8,1 /* Add null terminator */
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stxv 32+v0,0(r11)
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sldi r10,r9,56 /* stxvl wants size in top 8 bits */
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addi r11,r11,16 /* offset */
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stxvl 32+v1,r11,r10 /* Partial store */
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2020-11-12 16:12:24 +00:00
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#ifdef USE_AS_STPNCPY
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/* Compute pointer to last byte copied into dest. */
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add r3,r11,r8
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#endif
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2020-11-12 16:12:24 +00:00
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add r11,r11,r9
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sub r5,r5,r9
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b L(zero_padding)
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L(prep_tail3):
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addi r5,r5,-32
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L(count_tail3):
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vctzlsbb r8,v6 /* Number of trailing zeroes */
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L(tail3):
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addi r9,r8,1 /* Add null terminator */
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stxv 32+v0,0(r11)
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stxv 32+v1,16(r11)
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sldi r10,r9,56 /* stxvl wants size in top 8 bits */
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addi r11,r11,32 /* offset */
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stxvl 32+v2,r11,r10 /* Partial store */
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2020-11-12 16:12:24 +00:00
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#ifdef USE_AS_STPNCPY
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/* Compute pointer to last byte copied into dest. */
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add r3,r11,r8
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#endif
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2020-11-12 16:12:24 +00:00
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add r11,r11,r9
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sub r5,r5,r9
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b L(zero_padding)
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L(prep_tail4):
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addi r5,r5,-48
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vctzlsbb r8,v6 /* Number of trailing zeroes */
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L(tail4):
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addi r9,r8,1 /* Add null terminator */
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stxv 32+v0,0(r11)
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stxv 32+v1,16(r11)
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stxv 32+v2,32(r11)
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sldi r10,r9,56 /* stxvl wants size in top 8 bits */
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addi r11,r11,48 /* offset */
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stxvl 32+v3,r11,r10 /* Partial store */
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2020-11-12 16:12:24 +00:00
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#ifdef USE_AS_STPNCPY
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/* Compute pointer to last byte copied into dest. */
|
|
|
|
add r3,r11,r8
|
|
|
|
#endif
|
2020-11-12 16:12:24 +00:00
|
|
|
add r11,r11,r9
|
|
|
|
sub r5,r5,r9
|
|
|
|
|
|
|
|
/* This code pads the remainder of dest with NULL bytes. For large numbers
|
|
|
|
memset gives a better performance, 255 was chosen through experimentation.
|
|
|
|
*/
|
|
|
|
L(zero_padding):
|
|
|
|
cmpldi r5,255
|
|
|
|
bge L(zero_padding_memset)
|
|
|
|
|
|
|
|
L(zero_padding_loop):
|
|
|
|
cmpldi cr6,r5,16 /* Check if length was reached. */
|
|
|
|
ble cr6,L(zero_padding_end)
|
|
|
|
|
|
|
|
stxv v18,0(r11)
|
|
|
|
addi r11,r11,16
|
|
|
|
addi r5,r5,-16
|
|
|
|
|
|
|
|
b L(zero_padding_loop)
|
|
|
|
|
|
|
|
L(zero_padding_end):
|
|
|
|
sldi r10,r5,56 /* stxvl wants size in top 8 bits */
|
|
|
|
stxvl v18,r11,r10 /* Partial store */
|
|
|
|
blr
|
|
|
|
|
|
|
|
.align 4
|
|
|
|
L(zero_padding_memset):
|
|
|
|
std r30,-8(r1) /* Save r30 on the stack. */
|
|
|
|
cfi_offset(r30, -8)
|
|
|
|
mr r30,r3 /* Save the return value of strncpy. */
|
|
|
|
/* Prepare the call to memset. */
|
|
|
|
mr r3,r11 /* Pointer to the area to be zero-filled. */
|
|
|
|
li r4,0 /* Byte to be written (zero). */
|
|
|
|
|
|
|
|
/* We delayed the creation of the stack frame, as well as the saving of
|
|
|
|
the link register, because only at this point, we are sure that
|
|
|
|
doing so is actually needed. */
|
|
|
|
|
|
|
|
/* Save the link register. */
|
|
|
|
mflr r0
|
|
|
|
std r0,16(r1)
|
|
|
|
|
|
|
|
/* Create the stack frame. */
|
|
|
|
stdu r1,-FRAMESIZE(r1)
|
|
|
|
cfi_adjust_cfa_offset(FRAMESIZE)
|
|
|
|
cfi_offset(lr, 16)
|
|
|
|
|
|
|
|
bl MEMSET
|
|
|
|
#ifndef MEMSET_is_local
|
|
|
|
nop
|
|
|
|
#endif
|
|
|
|
|
|
|
|
ld r0,FRAMESIZE+16(r1)
|
|
|
|
|
|
|
|
mr r3,r30 /* Restore the return value of strncpy, i.e.:
|
2020-11-12 16:12:24 +00:00
|
|
|
dest. For stpncpy, the return value is the
|
|
|
|
same as return value of memset. */
|
2020-11-12 16:12:24 +00:00
|
|
|
ld r30,FRAMESIZE-8(r1) /* Restore r30. */
|
|
|
|
/* Restore the stack frame. */
|
|
|
|
addi r1,r1,FRAMESIZE
|
|
|
|
cfi_adjust_cfa_offset(-FRAMESIZE)
|
|
|
|
/* Restore the link register. */
|
|
|
|
mtlr r0
|
|
|
|
cfi_restore(lr)
|
|
|
|
blr
|
|
|
|
|
|
|
|
END (FUNC_NAME)
|
2020-11-12 16:12:24 +00:00
|
|
|
#ifndef USE_AS_STPNCPY
|
|
|
|
libc_hidden_builtin_def (strncpy)
|
|
|
|
#endif
|