forked from mirrors/linux
2874c5fd28
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
94 lines
2.1 KiB
ArmAsm
94 lines
2.1 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* OpenRISC memset.S
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*
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* Hand-optimized assembler version of memset for OpenRISC.
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* Algorithm inspired by several other arch-specific memset routines
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* in the kernel tree
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*
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* Copyright (C) 2015 Olof Kindgren <olof.kindgren@gmail.com>
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*/
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.global memset
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.type memset, @function
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memset:
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/* arguments:
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* r3 = *s
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* r4 = c
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* r5 = n
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* r13, r15, r17, r19 used as temp regs
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*/
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/* Exit if n == 0 */
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l.sfeqi r5, 0
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l.bf 4f
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/* Truncate c to char */
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l.andi r13, r4, 0xff
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/* Skip word extension if c is 0 */
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l.sfeqi r13, 0
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l.bf 1f
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/* Check for at least two whole words (8 bytes) */
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l.sfleui r5, 7
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/* Extend char c to 32-bit word cccc in r13 */
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l.slli r15, r13, 16 // r13 = 000c, r15 = 0c00
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l.or r13, r13, r15 // r13 = 0c0c, r15 = 0c00
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l.slli r15, r13, 8 // r13 = 0c0c, r15 = c0c0
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l.or r13, r13, r15 // r13 = cccc, r15 = c0c0
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1: l.addi r19, r3, 0 // Set r19 = src
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/* Jump to byte copy loop if less than two words */
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l.bf 3f
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l.or r17, r5, r0 // Set r17 = n
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/* Mask out two LSBs to check alignment */
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l.andi r15, r3, 0x3
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/* lsb == 00, jump to word copy loop */
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l.sfeqi r15, 0
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l.bf 2f
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l.addi r19, r3, 0 // Set r19 = src
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/* lsb == 01,10 or 11 */
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l.sb 0(r3), r13 // *src = c
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l.addi r17, r17, -1 // Decrease n
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l.sfeqi r15, 3
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l.bf 2f
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l.addi r19, r3, 1 // src += 1
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/* lsb == 01 or 10 */
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l.sb 1(r3), r13 // *(src+1) = c
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l.addi r17, r17, -1 // Decrease n
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l.sfeqi r15, 2
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l.bf 2f
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l.addi r19, r3, 2 // src += 2
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/* lsb == 01 */
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l.sb 2(r3), r13 // *(src+2) = c
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l.addi r17, r17, -1 // Decrease n
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l.addi r19, r3, 3 // src += 3
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/* Word copy loop */
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2: l.sw 0(r19), r13 // *src = cccc
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l.addi r17, r17, -4 // Decrease n
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l.sfgeui r17, 4
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l.bf 2b
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l.addi r19, r19, 4 // Increase src
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/* When n > 0, copy the remaining bytes, otherwise jump to exit */
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l.sfeqi r17, 0
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l.bf 4f
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/* Byte copy loop */
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3: l.addi r17, r17, -1 // Decrease n
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l.sb 0(r19), r13 // *src = cccc
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l.sfnei r17, 0
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l.bf 3b
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l.addi r19, r19, 1 // Increase src
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4: l.jr r9
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l.ori r11, r3, 0
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