newlib-cygwin/newlib/libc/machine/xtensa/strncpy.S

275 lines
6.4 KiB
ArmAsm

/* ANSI C standard library function strncpy.
Copyright (c) 2001-2008 Tensilica Inc.
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
#include "xtensa-asm.h"
.text
.begin schedule
.align 4
.literal_position
__strncpy_aux:
.Lsrc1mod2: // src address is odd
l8ui a8, a3, 0 // get byte 0
addi a3, a3, 1 // advance src pointer
s8i a8, a10, 0 // store byte 0
addi a4, a4, -1 // decrement n
beqz a4, .Lret // if n is zero
addi a10, a10, 1 // advance dst pointer
beqz a8, .Lfill // if byte 0 is zero
bbci.l a3, 1, .Lsrcaligned // if src is now word-aligned
.Lsrc2mod4: // src address is 2 mod 4
l8ui a8, a3, 0 // get byte 0
addi a4, a4, -1 // decrement n
s8i a8, a10, 0 // store byte 0
beqz a4, .Lret // if n is zero
addi a10, a10, 1 // advance dst pointer
beqz a8, .Lfill // if byte 0 is zero
l8ui a8, a3, 1 // get byte 0
addi a3, a3, 2 // advance src pointer
s8i a8, a10, 0 // store byte 0
addi a4, a4, -1 // decrement n
beqz a4, .Lret // if n is zero
addi a10, a10, 1 // advance dst pointer
bnez a8, .Lsrcaligned
j .Lfill
.Lret:
#if XTENSA_ESP32_PSRAM_CACHE_FIX
memw
#endif
leaf_return
.align 4
.global strncpy
.type strncpy, @function
strncpy:
leaf_entry sp, 16
/* a2 = dst, a3 = src */
mov a10, a2 // leave dst in return value register
beqz a4, .Lret // if n is zero
movi a11, MASK0
movi a5, MASK1
movi a6, MASK2
movi a7, MASK3
bbsi.l a3, 0, .Lsrc1mod2
bbsi.l a3, 1, .Lsrc2mod4
.Lsrcaligned:
/* Check if the destination is aligned. */
movi a8, 3
bnone a10, a8, .Laligned
j .Ldstunaligned
/* Fill the dst with zeros -- n is at least 1. */
.Lfill:
movi a9, 0
bbsi.l a10, 0, .Lfill1mod2
bbsi.l a10, 1, .Lfill2mod4
.Lfillaligned:
blti a4, 4, .Lfillcleanup
/* Loop filling complete words with zero. */
#if XCHAL_HAVE_LOOPS
srai a8, a4, 2
loop a8, 1f
s32i a9, a10, 0
addi a10, a10, 4
1: slli a8, a8, 2
sub a4, a4, a8
#else /* !XCHAL_HAVE_LOOPS */
1: s32i a9, a10, 0
addi a10, a10, 4
addi a4, a4, -4
bgei a4, 4, 1b
#endif /* !XCHAL_HAVE_LOOPS */
beqz a4, 2f
.Lfillcleanup:
/* Fill leftover (1 to 3) bytes with zero. */
s8i a9, a10, 0 // store byte 0
addi a4, a4, -1 // decrement n
addi a10, a10, 1
bnez a4, .Lfillcleanup
2:
#if XTENSA_ESP32_PSRAM_CACHE_FIX
memw
#endif
leaf_return
.Lfill1mod2: // dst address is odd
s8i a9, a10, 0 // store byte 0
addi a4, a4, -1 // decrement n
beqz a4, 2b // if n is zero
addi a10, a10, 1 // advance dst pointer
bbci.l a10, 1, .Lfillaligned // if dst is now word-aligned
.Lfill2mod4: // dst address is 2 mod 4
s8i a9, a10, 0 // store byte 0
addi a4, a4, -1 // decrement n
beqz a4, 2b // if n is zero
s8i a9, a10, 1 // store byte 1
addi a4, a4, -1 // decrement n
beqz a4, 2b // if n is zero
addi a10, a10, 2 // advance dst pointer
j .Lfillaligned
/* dst is word-aligned; src is word-aligned; n is at least 1. */
.align 4
#if XCHAL_HAVE_LOOPS
#if XCHAL_HAVE_DENSITY
/* (2 mod 4) alignment for loop instruction */
#else
/* (1 mod 4) alignment for loop instruction */
.byte 0
.byte 0
#endif
#endif
.Laligned:
#if XCHAL_HAVE_LOOPS
#if XCHAL_HAVE_DENSITY
_movi.n a8, 0 // set up for the maximum loop count
#else
_movi a8, 0 // set up for the maximum loop count
#endif
loop a8, 1f // loop forever (almost anyway)
blti a4, 5, .Ldstunaligned // n is near limit; do one at a time
l32i a8, a3, 0 // get word from src
addi a3, a3, 4 // advance src pointer
bnone a8, a11, .Lz0 // if byte 0 is zero
bnone a8, a5, .Lz1 // if byte 1 is zero
bnone a8, a6, .Lz2 // if byte 2 is zero
s32i a8, a10, 0 // store word to dst
addi a4, a4, -4 // decrement n
addi a10, a10, 4 // advance dst pointer
bnone a8, a7, .Lfill // if byte 3 is zero
1:
#else /* !XCHAL_HAVE_LOOPS */
1: blti a4, 5, .Ldstunaligned // n is near limit; do one at a time
l32i a8, a3, 0 // get word from src
addi a3, a3, 4 // advance src pointer
bnone a8, a11, .Lz0 // if byte 0 is zero
bnone a8, a5, .Lz1 // if byte 1 is zero
bnone a8, a6, .Lz2 // if byte 2 is zero
s32i a8, a10, 0 // store word to dst
addi a4, a4, -4 // decrement n
addi a10, a10, 4 // advance dst pointer
bany a8, a7, 1b // no zeroes
#endif /* !XCHAL_HAVE_LOOPS */
j .Lfill
.Lz0: /* Byte 0 is zero. */
#ifdef __XTENSA_EB__
movi a8, 0
#endif
s8i a8, a10, 0
addi a4, a4, -1 // decrement n
addi a10, a10, 1 // advance dst pointer
j .Lfill
.Lz1: /* Byte 1 is zero. */
#ifdef __XTENSA_EB__
extui a8, a8, 16, 16
#endif
s16i a8, a10, 0
addi a4, a4, -2 // decrement n
addi a10, a10, 2 // advance dst pointer
j .Lfill
.Lz2: /* Byte 2 is zero. */
#ifdef __XTENSA_EB__
extui a8, a8, 16, 16
#endif
s16i a8, a10, 0
movi a8, 0
s8i a8, a10, 2
addi a4, a4, -3 // decrement n
addi a10, a10, 3 // advance dst pointer
j .Lfill
.align 4
#if XCHAL_HAVE_LOOPS
#if XCHAL_HAVE_DENSITY
/* (2 mod 4) alignment for loop instruction */
#else
/* (1 mod 4) alignment for loop instruction */
.byte 0
.byte 0
#endif
#endif
.Ldstunaligned:
#if XCHAL_HAVE_LOOPS
#if XCHAL_HAVE_DENSITY
_movi.n a8, 0 // set up for the maximum loop count
#else
_movi a8, 0 // set up for the maximum loop count
#endif
loop a8, 2f // loop forever (almost anyway)
#endif
1: l8ui a8, a3, 0
addi a3, a3, 1
#if XTENSA_ESP32_PSRAM_CACHE_FIX
nop
nop
nop
#endif
s8i a8, a10, 0
addi a4, a4, -1
beqz a4, 3f
addi a10, a10, 1
#if XCHAL_HAVE_LOOPS
beqz a8, 2f
#else
bnez a8, 1b
#endif
2: j .Lfill
3:
#if XTENSA_ESP32_PSRAM_CACHE_FIX
memw
#endif
leaf_return
.end schedule
.size strncpy, . - strncpy