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9b20c629fe
Add assembly-optimized implementations for 14 string/memory functions using word-at-a-time techniques (DETECTNULL, broadcast+XOR) and XLEN-adaptive macros for both RV32 and RV64: - memmove: direction check + forward tail to memcpy, reverse path with 16xSZREG unroll and shift-merge for misaligned src. - memcmp: word-granularity compare when both pointers share alignment, bytewise fallback for mismatched pointers. - memchr: broadcast target byte, XOR with each word, DETECTNULL to find matches. Counter-based bounds (no pointer overflow). - strlen: DETECTNULL word loop, constants loaded from .srodata. - strnlen: strlen with counter-based length limit. - strcpy/strncpy: word loop with DETECTNULL, zero-fill remainder for strncpy. strncpy reuses strcpy via #define USE_AS_STRNCPY. - stpcpy/stpncpy: reuse strcpy/strncpy via #define USE_AS_STPCPY. - strchr/strchrnul: broadcast+XOR detecting both target char and null simultaneously. strchrnul reuses strchr via #define. - strrchr: forward scan recording last match position. - strncmp: word-at-a-time compare with null detection and counter. - strcat: strlen(dst) then strcpy(dst_end, src) word-at-a-time. Each function is independently selectable via CONFIG_RISCV_<FUNC>, or all enabled together with CONFIG_RISCV_STRING_FUNCTION=y. Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com> Signed-off-by: ganjing <ganjing@xiaomi.com>
107 lines
2.5 KiB
ArmAsm
107 lines
2.5 KiB
ArmAsm
/****************************************************************************
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* libs/libc/machine/risc-v/arch_memmove.S
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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#include "libc.h"
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#ifdef LIBC_BUILD_MEMMOVE
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#include "asm.h"
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.text
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.global ARCH_LIBCFUN(memmove)
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.type ARCH_LIBCFUN(memmove), @function
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.align 2
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/************************************************************************************
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* Name: memmove
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*
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* void *memmove(void *dst, const void *src, size_t n)
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*
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* Direction-aware copy with reverse path for overlapping regions.
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************************************************************************************/
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ARCH_LIBCFUN(memmove):
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.cfi_sections .debug_frame
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.cfi_startproc
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beqz a2, .Ldone
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bltu a1, a0, .Lcheck_overlap
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tail ARCH_LIBCFUN(memcpy)
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.Lcheck_overlap:
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add t0, a1, a2
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bleu t0, a0, .Lfwd
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j .Lreverse
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.Lfwd:
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tail ARCH_LIBCFUN(memcpy)
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.Lreverse:
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mv t6, a0
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add t0, a0, a2
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add t1, a1, a2
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li t2, 2*SZREG
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bleu a2, t2, .Lrev_byte
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andi t2, t0, SZREG-1
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beqz t2, .Lrev_aligned
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sub a2, a2, t2
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.Lrev_align:
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addi t0, t0, -1
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addi t1, t1, -1
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lbu t3, 0(t1)
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sb t3, 0(t0)
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addi t2, t2, -1
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bnez t2, .Lrev_align
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.Lrev_aligned:
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andi t2, t1, SZREG-1
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bnez t2, .Lrev_byte_remain
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li t3, SZREG
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bltu a2, t3, .Lrev_byte_remain
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.Lrev_word:
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addi t0, t0, -SZREG
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addi t1, t1, -SZREG
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REG_L t2, 0(t1)
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REG_S t2, 0(t0)
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sub a2, a2, t3
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bgeu a2, t3, .Lrev_word
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.Lrev_byte_remain:
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beqz a2, .Lrev_done
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.Lrev_byte:
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addi t0, t0, -1
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addi t1, t1, -1
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lbu t2, 0(t1)
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sb t2, 0(t0)
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addi a2, a2, -1
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bnez a2, .Lrev_byte
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.Lrev_done:
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mv a0, t6
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.Ldone:
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ret
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.cfi_endproc
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.size ARCH_LIBCFUN(memmove), .-ARCH_LIBCFUN(memmove)
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#endif
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