score/src/memoryallocate.c

0001 /**
0002  * @file
0003  *
0004  * @ingroup RTEMSScoreMemory
0005  *
0006  * @brief This source file contains the implementation of
0007  *   _Memory_Allocate().
0008  */
0009
0010 /*
0011  * SPDX-License-Identifier: BSD-2-Clause
0012  *
0013  * Copyright (C) 2018, 2019 embedded brains GmbH & Co. KG
0014  *
0015  * Redistribution and use in source and binary forms, with or without
0016  * modification, are permitted provided that the following conditions
0017  * are met:
0018  * 1. Redistributions of source code must retain the above copyright
0019  *    notice, this list of conditions and the following disclaimer.
0020  * 2. Redistributions in binary form must reproduce the above copyright
0021  *    notice, this list of conditions and the following disclaimer in the
0022  *    documentation and/or other materials provided with the distribution.
0023  *
0024  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0025  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0026  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0027  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0028  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0029  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0030  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0031  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0032  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0033  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0034  * POSSIBILITY OF SUCH DAMAGE.
0035  */
0036
0037 #ifdef HAVE_CONFIG_H
0038 #include "config.h"
0039 #endif
0040
0041 #include <rtems/score/memory.h>
0042
0043 void *_Memory_Allocate(
0044   const Memory_Information *information,
0045   uintptr_t                 size,
0046   uintptr_t                 alignment
0047 )
0048 {
0049   Memory_Area       *area;
0050   const Memory_Area *end;
0051   uintptr_t          alignment_mask;
0052
0053   area = &information->areas[ 0 ];
0054   end = &information->areas[ information->count ];
0055   alignment_mask = alignment - 1;
0056
0057   while ( area != end ) {
0058     uintptr_t alloc_begin;
0059     uintptr_t alloc_end;
0060
0061     alloc_begin = (uintptr_t) area->free;
0062     alloc_begin += alignment_mask;
0063     alloc_begin &= ~alignment_mask;
0064     alloc_end = alloc_begin + size;
0065
0066     if ( alloc_begin <= alloc_end && alloc_end <= (uintptr_t) area->end ) {
0067       area->free = (void *) alloc_end;
0068
0069       return (void *) alloc_begin;
0070     }
0071
0072     ++area;
0073   }
0074
0075   return NULL;
0076 }