mirror of
https://github.com/pnx/m16vm
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69 lines
1.7 KiB
C
69 lines
1.7 KiB
C
/* mm.c
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*
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* Copyright (C) 2012,2014,2018-2019 Henrik Hautakoski <henrik.hautakoski@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "mm.h"
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#ifndef MEM_SIZE
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/* Set a default memory size. (2^16) */
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#define MEM_SIZE 65536
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#endif
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// Get a WORD aligned (16-bit) address.
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// Casts the 8-bit pointer (mm_base_addr) to 16-bit (WORD) and add offset.
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#define addr_align_word(offset) \
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(((uint16_t*) mm_base_addr) + (offset))
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#define EXCEPTION_STRING "Runtime exception: Memory address '%u' is out of bounds.\n"
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uint8_t *mm_base_addr = NULL;
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#define __check_bounds(addr) \
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if ((addr) + 1 > MEM_SIZE) { \
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fprintf(stderr, EXCEPTION_STRING, addr);\
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exit(1); \
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}
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void mm_init() {
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mm_base_addr = (uint8_t*) malloc(MEM_SIZE);
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}
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void mm_exit() {
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if (mm_base_addr) {
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free(mm_base_addr);
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mm_base_addr = NULL;
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}
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}
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void mm_sw(uint16_t addr, int16_t value) {
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__check_bounds(addr);
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*addr_align_word(addr) = value;
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}
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int16_t mm_lw(uint16_t addr) {
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__check_bounds(addr);
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return *addr_align_word(addr);
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}
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