esp-open-rtos/extras/spiffs/unaligned_memcpy.S

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/**
* The MIT License (MIT)
*
* Copyright (c) 2016 sheinz (https://github.com/sheinz)
*
* 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.
*/
.text
.section .iram1.text, "x"
.literal_position
/**
* Copy unaligned data to 4-byte aligned buffer.
*/
.align 4
.global memcpy_unaligned_src
.type memcpy_unaligned_src, @function
memcpy_unaligned_src:
/* a2: dst, a3: src, a4: size */
ssa8l a3
srli a3, a3, 2
slli a3, a3, 2
beqz a4, u_src_end
l32i a6, a3, 0
u_src_loop:
l32i a7, a3, 4
src a8, a7, a6
memw
s32i a8, a2, 0
mov a6, a7
addi a3, a3, 4
addi a2, a2, 4
addi a4, a4, -1
bnez a4, u_src_loop
u_src_end:
movi a2, 0
ret.n
/**
* Copy data from 4-byte aligned source to unaligned destination buffer.
*/
.align 4
.global memcpy_unaligned_dst
.type memcpy_unaligned_dst, @function
memcpy_unaligned_dst:
/* a2: dst, a3: src, a4: size */
beqz.n a4, u_dst_end
extui a5, a4, 0, 2
beqz.n a5, aligned_dst_loop
u_dst_loop:
/* Load data word */
memw
l32i.n a5, a3, 0
/* Save byte number 0 */
s8i a5, a2, 0
addi.n a4, a4, -1
beqz a4, u_dst_end
addi.n a2, a2, 1
/* Shift and save byte number 1 */
srli a5, a5, 8
s8i a5, a2, 0
addi.n a4, a4, -1
beqz a4, u_dst_end
addi.n a2, a2, 1
/* Shift and save byte number 2 */
srli a5, a5, 8
s8i a5, a2, 0
addi.n a4, a4, -1
beqz a4, u_dst_end
addi.n a2, a2, 1
/* Shift and save byte number 3 */
srli a5, a5, 8
s8i a5, a2, 0
addi.n a4, a4, -1
addi.n a2, a2, 1
/* Next word */
addi.n a3, a3, 4
bnez.n a4, u_dst_loop
ret.n
aligned_dst_loop:
memw
l32i a5, a3, 0
s32i a5, a2, 0
addi.n a3, a3, 4
addi.n a2, a2, 4
addi.n a4, a4, -4
bnez.n a4, aligned_dst_loop
u_dst_end: ret.n