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219 lines
4.8 KiB
ArmAsm
219 lines
4.8 KiB
ArmAsm
/* Optimized strncmp implementation using basic LoongArch instructions.
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Copyright (C) 2023-2024 Free Software Foundation, Inc.
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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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#include <sys/regdef.h>
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#include <sys/asm.h>
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#if IS_IN (libc)
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# define STRNCMP __strncmp_aligned
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#else
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# define STRNCMP strncmp
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#endif
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LEAF(STRNCMP, 6)
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beqz a2, L(ret0)
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lu12i.w a5, 0x01010
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andi a3, a0, 0x7
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ori a5, a5, 0x101
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andi a4, a1, 0x7
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bstrins.d a5, a5, 63, 32
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li.d t7, -1
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li.d t8, 8
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addi.d a2, a2, -1
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slli.d a6, a5, 7
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bne a3, a4, L(unaligned)
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bstrins.d a0, zero, 2, 0
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bstrins.d a1, zero, 2, 0
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ld.d t0, a0, 0
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ld.d t1, a1, 0
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slli.d t2, a3, 3
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sub.d t5, t8, a3
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srl.d t3, t7, t2
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srl.d t0, t0, t2
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srl.d t1, t1, t2
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orn t0, t0, t3
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orn t1, t1, t3
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sub.d t2, t0, a5
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andn t3, a6, t0
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and t2, t2, t3
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bne t0, t1, L(al_end)
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sltu t4, a2, t5
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sub.d a2, a2, t5
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L(al_loop):
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or t4, t2, t4
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bnez t4, L(ret0)
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ldx.d t0, a0, t8
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ldx.d t1, a1, t8
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addi.d t8, t8, 8
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sltui t4, a2, 8
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addi.d a2, a2, -8
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sub.d t2, t0, a5
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andn t3, a6, t0
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and t2, t2, t3
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beq t0, t1, L(al_loop)
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addi.d a2, a2, 8
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L(al_end):
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xor t3, t0, t1
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or t2, t2, t3
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ctz.d t2, t2
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srli.d t4, t2, 3
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bstrins.d t2, zero, 2, 0
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srl.d t0, t0, t2
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srl.d t1, t1, t2
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andi t0, t0, 0xff
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andi t1, t1, 0xff
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sltu t2, a2, t4
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sub.d a0, t0, t1
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masknez a0, a0, t2
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jr ra
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L(ret0):
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move a0, zero
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jr ra
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nop
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L(unaligned):
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slt a7, a4, a3
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xor t0, a0, a1
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maskeqz t0, t0, a7
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xor a0, a0, t0
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xor a1, a1, t0
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andi a3, a0, 0x7
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andi a4, a1, 0x7
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bstrins.d a0, zero, 2, 0
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bstrins.d a1, zero, 2, 0
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ld.d t4, a0, 0
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ld.d t1, a1, 0
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slli.d t2, a3, 3
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slli.d t3, a4, 3
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srl.d t5, t7, t3
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srl.d t0, t4, t2
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srl.d t1, t1, t3
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orn t0, t0, t5
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orn t1, t1, t5
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bne t0, t1, L(not_equal)
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sub.d t6, t8, a4
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sub.d a4, t2, t3
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sll.d t2, t7, t2
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sub.d t5, t8, a3
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orn t4, t4, t2
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sub.d t2, t4, a5
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andn t3, a6, t4
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sltu t7, a2, t5
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and t2, t2, t3
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sub.d a3, zero, a4
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or t2, t2, t7
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bnez t2, L(un_end)
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sub.d t7, t5, t6
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sub.d a2, a2, t5
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sub.d t6, t8, t7
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L(un_loop):
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srl.d t5, t4, a4
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ldx.d t4, a0, t8
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ldx.d t1, a1, t8
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addi.d t8, t8, 8
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sll.d t0, t4, a3
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or t0, t0, t5
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bne t0, t1, L(loop_not_equal)
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sub.d t2, t4, a5
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andn t3, a6, t4
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sltui t5, a2, 8
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and t2, t2, t3
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addi.d a2, a2, -8
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or t3, t2, t5
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beqz t3, L(un_loop)
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addi.d a2, a2, 8
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L(un_end):
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sub.d t2, t0, a5
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andn t3, a6, t0
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sltu t5, a2, t6
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and t2, t2, t3
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or t2, t2, t5
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bnez t2, L(ret0)
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ldx.d t1, a1, t8
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srl.d t0, t4, a4
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sub.d a2, a2, t6
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L(not_equal):
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sub.d t2, t0, a5
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andn t3, a6, t0
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xor t4, t0, t1
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and t2, t2, t3
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or t2, t2, t4
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ctz.d t2, t2
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bstrins.d t2, zero, 2, 0
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srli.d t4, t2, 3
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srl.d t0, t0, t2
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srl.d t1, t1, t2
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andi t0, t0, 0xff
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andi t1, t1, 0xff
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sub.d t2, t0, t1
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sub.d t3, t1, t0
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masknez t0, t2, a7
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maskeqz t1, t3, a7
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sltu t2, a2, t4
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or a0, t0, t1
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masknez a0, a0, t2
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jr ra
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L(loop_not_equal):
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add.d a2, a2, t7
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b L(not_equal)
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END(STRNCMP)
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libc_hidden_builtin_def (STRNCMP)
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