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70 lines
1.9 KiB
C++
70 lines
1.9 KiB
C++
/*
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* \brief ARM-specific memcpy using VFP
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* \author Sebastian Sumpf
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* \date 2013-06-19
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*
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* Should work for VFPv2, VFPv3, and Advanced SIMD.
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*/
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/*
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* Copyright (C) 2012-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#ifndef _INCLUDE__ARM__VFP__STRING_H_
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#define _INCLUDE__ARM__VFP__STRING_H_
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namespace Genode {
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/**
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* Copy memory block
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*
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* \param dst destination memory block
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* \param src source memory block
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* \param size number of bytes to copy
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*
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* \return Number of bytes not copied
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*/
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inline size_t memcpy_cpu(void *dst, const void *src, size_t size)
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{
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unsigned char *d = (unsigned char *)dst, *s = (unsigned char *)src;
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/* check 4 byte; alignment */
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size_t d_align = (size_t)d & 0x3;
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size_t s_align = (size_t)s & 0x3;
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/* only same alignments work for the following loops */
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if (d_align != s_align)
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return size;
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/* copy to 4 byte alignment */
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for (; (size > 0) && (s_align > 0) && (s_align < 4);
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s_align++, *d++ = *s++, size--);
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/* copy 64 byte chunks using FPU */
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for (; size >= 64; size -= 64)
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asm volatile ("pld [%0, #0xc0] \n\t"
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"vldm %0!,{d0-d7} \n\t"
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"vstm %1!,{d0-d7} \n\t"
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: "+r"(s), "+r" (d)
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:: "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7");
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/* copy left over 32 byte chunk */
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for (; size >= 32; size -= 32)
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asm volatile ("ldmia %0!, {r3 - r10} \n\t"
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"stmia %1!, {r3 - r10} \n\t"
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: "+r" (s), "+r" (d)
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:: "r3","r4","r5","r6","r7","r8","r9","r10");
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for(; size >= 4; size -= 4)
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asm volatile ("ldr r3, [%0], #4 \n\t"
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"str r3, [%1], #4 \n\t"
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: "+r" (s), "+r" (d)
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:: "r3");
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return size;
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}
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}
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#endif /* _INCLUDE__ARM__VFP__STRING_H_ */
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