mem.h

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/*
 * Copyright (c) 2013 Daniel Loffgren
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#ifndef v6502_mem_h
#define v6502_mem_h

#include <stdint.h>
#include <stddef.h>

#ifndef YES

#define YES 1
#endif

#ifndef NO

#define NO  0
#endif

// Memory Starts
#define v6502_memoryStartWorkMemory         0x0000

#define v6502_memoryStartStack              0x0100

#define v6502_memoryStartPPURegisters       0x2000

#define v6502_memoryStartAPURegisters       0x4000

#define v6502_memoryStartExpansionRom       0x4020

#define v6502_memoryStartSRAM               0x6000

#define v6502_memoryStartPRGROM             0x8000

#define v6502_memoryStartInterruptVectors   0xFFFA

#define v6502_memoryStartCeiling            0xFFFF

// Memory Blob Sizes
#define v6502_memorySizeWorkMemory          0x0800

#define v6502_memorySizePPURegisters        0x0008

#define v6502_memorySizeInterruptVectors    (v6502_memoryStartCeiling - v6502_memoryStartInterruptVectors)

// Vector Locations
#define v6502_memoryVectorNMILow            0xFFFA

#define v6502_memoryVectorNMIHigh           0xFFFB

#define v6502_memoryVectorResetLow          0xFFFC

#define v6502_memoryVectorResetHigh         0xFFFD

#define v6502_memoryVectorInterruptLow      0xFFFE

#define v6502_memoryVectorInterruptHigh     0xFFFF

#define BYTE_MAX 0xFF

/* Forward declaration needed for circular dependency of mapping function and structures */
struct _v6502_memory;
typedef uint8_t (v6502_readFunction)(struct _v6502_memory *memory, uint16_t offset, int trap, void *context);
typedef void (v6502_writeFunction)(struct _v6502_memory *memory, uint16_t offset, uint8_t value, void *context);

typedef struct {
    uint16_t start;
    size_t size;
    v6502_readFunction *read;
    v6502_writeFunction *write;
    void *context;
} v6502_mappedRange;

typedef struct  _v6502_memory  {
    uint8_t *bytes;
    size_t size;
    void(*fault_callback)(void *context, const char *reason);
    void *fault_context;
    v6502_mappedRange *mappedRanges;
    size_t rangeCount;
    int mapCacheEnabled;
    v6502_readFunction **readCache;
    v6502_writeFunction **writeCache;
    void **contextCache;
} v6502_memory;

v6502_memory *v6502_createMemory(size_t size);
void v6502_destroyMemory(v6502_memory *memory);
void v6502_loadExpansionRomIntoMemory(v6502_memory *memory, uint8_t *rom, uint16_t size);
int v6502_map(v6502_memory *memory, uint16_t start, size_t size, v6502_readFunction *read, v6502_writeFunction *write, void *context);
uint8_t v6502_read(v6502_memory *memory, uint16_t offset, int trap);
void v6502_write(v6502_memory *memory, uint16_t offset, uint8_t value);
v6502_mappedRange *v6502_mappedRangeForOffset(v6502_memory *memory, uint16_t offset);
int8_t v6502_signedValueOfByte(uint8_t byte);
uint8_t v6502_byteValueOfSigned(int8_t i);
#endif