101 lines
3.2 KiB
C
101 lines
3.2 KiB
C
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/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2018 Scott Shawcroft for Adafruit Industries
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "supervisor/memory.h"
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#include <stddef.h>
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#define CIRCUITPY_SUPERVISOR_ALLOC_COUNT 8
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static supervisor_allocation allocations[CIRCUITPY_SUPERVISOR_ALLOC_COUNT];
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// We use uint32_t* to ensure word (4 byte) alignment.
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uint32_t* low_address;
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uint32_t* high_address;
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extern uint32_t _ebss;
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extern uint32_t _estack;
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void memory_init(void) {
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low_address = &_ebss;
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high_address = &_estack;
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// snag 3k for stack
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allocate_memory(1024*4, true);
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}
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void free_memory(supervisor_allocation* allocation) {
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uint8_t index = 0;
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bool found = false;
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for (index = 0; index < CIRCUITPY_SUPERVISOR_ALLOC_COUNT; index++) {
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found = allocation == &allocations[index];
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if (found) {
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break;
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}
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}
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if (allocation->ptr == high_address) {
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high_address += allocation->length / 4;
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} else if (allocation->ptr + allocation->length / 4 == low_address) {
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low_address = allocation->ptr;
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}
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allocation->ptr = NULL;
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}
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supervisor_allocation* allocate_remaining_memory(void) {
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if (low_address == high_address) {
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return NULL;
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}
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return allocate_memory((high_address - low_address) * 4, false);
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}
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supervisor_allocation* allocate_memory(uint32_t length, bool high) {
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if ((high_address - low_address) * 4 < (int32_t) length) {
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return NULL;
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}
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uint8_t index = 0;
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int8_t direction = 1;
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if (high) {
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index = CIRCUITPY_SUPERVISOR_ALLOC_COUNT - 1;
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direction = -1;
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}
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for (; index < CIRCUITPY_SUPERVISOR_ALLOC_COUNT; index += direction) {
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if (allocations[index].ptr == NULL) {
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break;
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}
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}
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if (index >= CIRCUITPY_SUPERVISOR_ALLOC_COUNT) {
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return NULL;
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}
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supervisor_allocation* alloc = &allocations[index];
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if (high) {
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high_address -= length / 4;
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alloc->ptr = high_address;
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} else {
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alloc->ptr = low_address;
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low_address += length / 4;
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}
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alloc->length = length;
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return alloc;
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}
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