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738a11f600
SpeccySE/arm9/source/saveload.c
Dave Bernazzani 738a11f600 Compress save/load state files
2025-03-31 08:02:06 -04:00

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// =====================================================================================
// Copyright (c) 2025 Dave Bernazzani (wavemotion-dave)
//
// Copying and distribution of this emulator, its source code and associated
// readme files, with or without modification, are permitted in any medium without
// royalty provided this copyright notice is used and wavemotion-dave (Phoenix-Edition),
// Alekmaul (original port) and Marat Fayzullin (ColEM core) are thanked profusely.
//
// The SpeccyDS emulator is offered as-is, without any warranty. Please see readme.md
// =====================================================================================
#include <nds.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fat.h>
#include <dirent.h>
#include "SpeccyDS.h"
#include "CRC32.h"
#include "cpu/z80/Z80_interface.h"
#include "SpeccyUtils.h"
#include "printf.h"
#define SPECCYDS_SAVE_VER 0x0001 // Change this if the basic format of the .SAV file changes. Invalidates older .sav files.
// -----------------------------------------------------------------------------------------------------
// Since the main MemoryMap[] can point to differt things (RAM, ROM, BIOS, etc) and since we can't rely
// on the memory being in the same spot on subsequent versions of the emulator... we need to save off
// the type and the offset so that we can patch it back together when we load back a saved state.
// -----------------------------------------------------------------------------------------------------
struct RomOffset
{
u8 type;
u32 offset;
};
struct RomOffset Offsets[8];
#define TYPE_ROM 0
#define TYPE_RAM 1
#define TYPE_BIOS 2
#define TYPE_OTHER 5
/*********************************************************************************
* Save the current state - save everything we need to a single .sav file.
********************************************************************************/
u8 spare[512] = {0x00}; // We keep some spare bytes so we can use them in the future without changing the structure
static char szLoadFile[256]; // We build the filename out of the base filename and tack on .sav, .ee, etc.
static char tmpStr[32];
void spectrumSaveState()
{
size_t retVal;
// Return to the original path
chdir(initial_path);
// Init filename = romname and SAV in place of ROM
DIR* dir = opendir("sav");
if (dir) closedir(dir); // Directory exists... close it out and move on.
else mkdir("sav", 0777); // Otherwise create the directory...
sprintf(szLoadFile,"sav/%s", initial_file);
int len = strlen(szLoadFile);
szLoadFile[len-3] = 's';
szLoadFile[len-2] = 'a';
szLoadFile[len-1] = 'v';
strcpy(tmpStr,"SAVING...");
DSPrint(4,0,0,tmpStr);
FILE *handle = fopen(szLoadFile, "wb+");
if (handle != NULL)
{
// Write Version
u16 save_ver = SPECCYDS_SAVE_VER;
retVal = fwrite(&save_ver, sizeof(u16), 1, handle);
// Write CZ80 CPU
retVal = fwrite(&CPU, sizeof(CPU), 1, handle);
// Write AY Chip info
retVal = fwrite(&myAY, sizeof(myAY), 1, handle);
// And the Memory Map - we must only save offsets so that this is generic when we change code and memory shifts...
for (u8 i=0; i<8; i++)
{
if ((MemoryMap[i] >= ROM_Memory) && (MemoryMap[i] < ROM_Memory+(sizeof(ROM_Memory))))
{
Offsets[i].type = TYPE_ROM;
Offsets[i].offset = MemoryMap[i] - ROM_Memory;
}
else if ((MemoryMap[i] >= RAM_Memory) && (MemoryMap[i] < RAM_Memory+(sizeof(RAM_Memory))))
{
Offsets[i].type = TYPE_RAM;
Offsets[i].offset = MemoryMap[i] - RAM_Memory;
}
else
{
Offsets[i].type = TYPE_OTHER;
Offsets[i].offset = (u32)MemoryMap[i];
}
}
if (retVal) retVal = fwrite(Offsets, sizeof(Offsets),1, handle);
// And now a bunch of ZX Spectrum related vars...
if (retVal) retVal = fwrite(&portFE, sizeof(portFE), 1,handle);
if (retVal) retVal = fwrite(&portFD, sizeof(portFD), 1, handle);
if (retVal) retVal = fwrite(&zx_AY_enabled, sizeof(zx_AY_enabled), 1, handle);
if (retVal) retVal = fwrite(&flash_timer, sizeof(flash_timer), 1, handle);
if (retVal) retVal = fwrite(&bFlash, sizeof(bFlash), 1, handle);
if (retVal) retVal = fwrite(&zx_128k_mode, sizeof(zx_128k_mode), 1, handle);
if (retVal) retVal = fwrite(&zx_ScreenRendering, sizeof(zx_ScreenRendering), 1, handle);
if (retVal) retVal = fwrite(&zx_current_line, sizeof(zx_current_line), 1, handle);
if (retVal) retVal = fwrite(&num_blocks_available, sizeof(num_blocks_available), 1, handle);
if (retVal) retVal = fwrite(&current_block, sizeof(current_block), 1, handle);
if (retVal) retVal = fwrite(&tape_state, sizeof(tape_state), 1, handle);
if (retVal) retVal = fwrite(&current_block_data_idx, sizeof(current_block_data_idx), 1, handle);
if (retVal) retVal = fwrite(&tape_bytes_processed, sizeof(tape_bytes_processed), 1, handle);
if (retVal) retVal = fwrite(&header_pulses, sizeof(header_pulses), 1, handle);
if (retVal) retVal = fwrite(&current_bit, sizeof(current_bit), 1, handle);
if (retVal) retVal = fwrite(&lastBitSent, sizeof(lastBitSent), 1, handle);
if (retVal) retVal = fwrite(&current_bytes_this_block, sizeof(current_bytes_this_block), 1, handle);
if (retVal) retVal = fwrite(&handle_last_bits, sizeof(handle_last_bits), 1, handle);
if (retVal) retVal = fwrite(&custom_pulse_idx, sizeof(custom_pulse_idx), 1, handle);
// Save Z80 Memory Map... either 48K for 128K
u8 *ptr = RAM_Memory+0x4000;
u32 mem_size = 0xC000;
if (zx_128k_mode)
{
ptr = RAM_Memory128;
mem_size = 0x20000;
}
// Simple Run-Length-Encoding saves us on lots of zeroed memory...
for (u32 i=0; i<mem_size; i++)
{
u8 count = 0;
while (ptr[i] == 0x00)
{
if (++count == 255) break;
i++;
}
if (count)
{
i--;
u8 zero = 0x00;
if (retVal) retVal = fwrite(&zero, 1, 1, handle);
if (retVal) retVal = fwrite(&count, 1, 1, handle);
}
else
{
if (retVal) retVal = fwrite(&ptr[i], 1, 1, handle);
}
}
strcpy(tmpStr, (retVal ? "OK ":"ERR"));
DSPrint(13,0,0,tmpStr);
WAITVBL;WAITVBL;WAITVBL;WAITVBL;WAITVBL;WAITVBL;
DSPrint(4,0,0," ");
DisplayStatusLine(true);
}
else {
strcpy(tmpStr,"Error opening SAV file ...");
}
fclose(handle);
}
/*********************************************************************************
* Load the current state - read everything back from the .sav file.
********************************************************************************/
void spectrumLoadState()
{
size_t retVal;
// Return to the original path
chdir(initial_path);
// Init filename = romname and .SAV in place of ROM
sprintf(szLoadFile,"sav/%s", initial_file);
int len = strlen(szLoadFile);
szLoadFile[len-3] = 's';
szLoadFile[len-2] = 'a';
szLoadFile[len-1] = 'v';
FILE* handle = fopen(szLoadFile, "rb");
if (handle != NULL)
{
strcpy(tmpStr,"LOADING...");
DSPrint(4,0,0,tmpStr);
// Read Version
u16 save_ver = 0xBEEF;
retVal = fread(&save_ver, sizeof(u16), 1, handle);
if (save_ver == SPECCYDS_SAVE_VER)
{
// Load CZ80 CPU
retVal = fread(&CPU, sizeof(CPU), 1, handle);
// Load AY Chip info
if (retVal) retVal = fread(&myAY, sizeof(myAY), 1, handle);
// Load back the Memory Map - these were saved as offsets so we must reconstruct actual pointers
if (retVal) retVal = fread(Offsets, sizeof(Offsets),1, handle);
for (u8 i=0; i<8; i++)
{
if (Offsets[i].type == TYPE_ROM)
{
MemoryMap[i] = (u8 *) (ROM_Memory + Offsets[i].offset);
}
else if (Offsets[i].type == TYPE_RAM)
{
MemoryMap[i] = (u8 *) (RAM_Memory + Offsets[i].offset);
}
else // TYPE_OTHER - this is just a pointer to memory
{
MemoryMap[i] = (u8 *) (Offsets[i].offset);
}
}
}
else retVal = 0;
// And now a bunch of ZX Spectrum related vars...
if (retVal) retVal = fread(&portFE, sizeof(portFE), 1,handle);
if (retVal) retVal = fread(&portFD, sizeof(portFD), 1, handle);
if (retVal) retVal = fread(&zx_AY_enabled, sizeof(zx_AY_enabled), 1, handle);
if (retVal) retVal = fread(&flash_timer, sizeof(flash_timer), 1, handle);
if (retVal) retVal = fread(&bFlash, sizeof(bFlash), 1, handle);
if (retVal) retVal = fread(&zx_128k_mode, sizeof(zx_128k_mode), 1, handle);
if (retVal) retVal = fread(&zx_ScreenRendering, sizeof(zx_ScreenRendering), 1, handle);
if (retVal) retVal = fread(&zx_current_line, sizeof(zx_current_line), 1, handle);
if (retVal) retVal = fread(&num_blocks_available, sizeof(num_blocks_available), 1, handle);
if (retVal) retVal = fread(&current_block, sizeof(current_block), 1, handle);
if (retVal) retVal = fread(&tape_state, sizeof(tape_state), 1, handle);
if (retVal) retVal = fread(&current_block_data_idx, sizeof(current_block_data_idx), 1, handle);
if (retVal) retVal = fread(&tape_bytes_processed, sizeof(tape_bytes_processed), 1, handle);
if (retVal) retVal = fread(&header_pulses, sizeof(header_pulses), 1, handle);
if (retVal) retVal = fread(&current_bit, sizeof(current_bit), 1, handle);
if (retVal) retVal = fread(&lastBitSent, sizeof(lastBitSent), 1, handle);
if (retVal) retVal = fread(&current_bytes_this_block, sizeof(current_bytes_this_block), 1, handle);
if (retVal) retVal = fread(&handle_last_bits, sizeof(handle_last_bits), 1, handle);
if (retVal) retVal = fread(&custom_pulse_idx, sizeof(custom_pulse_idx), 1, handle);
// Load Z80 Memory Map... either 48K for 128K
u8 *ptr = RAM_Memory+0x4000;
u32 mem_size = 0xC000;
if (zx_128k_mode)
{
ptr = RAM_Memory128;
mem_size = 0x20000;
}
// Simple Run-Length-Encoding saves us on lots of zeroed memory...
for (u32 i=0; i<mem_size; i++)
{
u8 count;
if (retVal)
{
retVal = fread(&ptr[i], 1, 1, handle);
if (ptr[i] == 0x00) // RLE
{
fread(&count, 1, 1, handle);
while (--count)
{
ptr[i++] = 0x00;
}
}
}
}
strcpy(tmpStr, (retVal ? "OK ":"ERR"));
DSPrint(13,0,0,tmpStr);
WAITVBL;WAITVBL;WAITVBL;WAITVBL;WAITVBL;WAITVBL;
DSPrint(4,0,0," ");
DisplayStatusLine(true);
}
else
{
DSPrint(4,0,0,"NO SAVED GAME");
WAITVBL;WAITVBL;WAITVBL;WAITVBL;WAITVBL;WAITVBL;
DSPrint(4,0,0," ");
}
fclose(handle);
}
// End of file
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