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bus-sub-m68k.c
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/* TODO: */
/* https://bitbucket.org/eke/genesis-plus-gx/issues/29/mega-cd-support */
/* https://gendev.spritesmind.net/forum/viewtopic.php?t=3020 */
#include "bus-sub-m68k.h"
#include <assert.h>
#include "bus-main-m68k.h"
#include "cdda.h"
#include "log.h"
static cc_u16f MCDM68kReadByte(const void* const user_data, const cc_u32f address, const CycleMegaCD target_cycle)
{
const cc_bool is_odd = (address & 1) != 0;
return (MCDM68kReadCallbackWithCycle(user_data, (address & 0xFFFFFF) / 2, !is_odd, is_odd, target_cycle) >> (is_odd ? 0 : 8)) & 0xFF;
}
static cc_u16f MCDM68kReadWord(const void* const user_data, const cc_u32f address, const CycleMegaCD target_cycle)
{
assert(address % 2 == 0);
return MCDM68kReadCallbackWithCycle(user_data, (address & 0xFFFFFF) / 2, cc_true, cc_true, target_cycle);
}
static cc_u16f MCDM68kReadLongword(const void* const user_data, const cc_u32f address, const CycleMegaCD target_cycle)
{
cc_u32f longword;
longword = (cc_u32f)MCDM68kReadWord(user_data, address + 0, target_cycle) << 16;
longword |= (cc_u32f)MCDM68kReadWord(user_data, address + 2, target_cycle) << 0;
return longword;
}
static void MCDM68kWriteByte(const void* const user_data, const cc_u32f address, const cc_u16f value, const CycleMegaCD target_cycle)
{
const cc_bool is_odd = (address & 1) != 0;
MCDM68kWriteCallbackWithCycle(user_data, (address & 0xFFFFFF) / 2, !is_odd, is_odd, value << (is_odd ? 0 : 8), target_cycle);
}
static void MCDM68kWriteWord(const void* const user_data, const cc_u32f address, const cc_u16f value, const CycleMegaCD target_cycle)
{
assert(address % 2 == 0);
MCDM68kWriteCallbackWithCycle(user_data, (address & 0xFFFFFF) / 2, cc_true, cc_true, value, target_cycle);
}
static void ROMSEEK(const ClownMDEmu* const clownmdemu, const ClownMDEmu_Callbacks* const frontend_callbacks, const cc_u32f starting_sector, const cc_u32f total_sectors)
{
CDC_Stop(&clownmdemu->state->mega_cd.cdc);
CDC_Seek(&clownmdemu->state->mega_cd.cdc, frontend_callbacks->cd_sector_read, frontend_callbacks->user_data, starting_sector, total_sectors);
frontend_callbacks->cd_seeked((void*)frontend_callbacks->user_data, starting_sector);
}
static void CDCSTART(const ClownMDEmu* const clownmdemu, const ClownMDEmu_Callbacks* const frontend_callbacks)
{
CDDA_SetPlaying(&clownmdemu->state->mega_cd.cdda, cc_false);
CDC_Start(&clownmdemu->state->mega_cd.cdc, frontend_callbacks->cd_sector_read, frontend_callbacks->user_data);
}
/* TODO: Move this to its own file? */
static void MegaCDBIOSCall(const ClownMDEmu* const clownmdemu, const void* const user_data, const ClownMDEmu_Callbacks* const frontend_callbacks, const CycleMegaCD target_cycle)
{
/* TODO: None of this shit is accurate at all. */
/* TODO: Devon's notes on the CDC commands:
https://forums.sonicretro.org/index.php?posts/1052926/ */
const cc_u16f command = clownmdemu->mcd_m68k->data_registers[0] & 0xFFFF;
switch (command)
{
case 0x02:
/* MSCSTOP */
/* TODO: Make this actually stop and not just pause. */
/* Fallthrough */
case 0x03:
/* MSCPAUSEON */
CDDA_SetPaused(&clownmdemu->state->mega_cd.cdda, cc_true);
break;
case 0x04:
/* MSCPAUSEOFF */
CDDA_SetPaused(&clownmdemu->state->mega_cd.cdda, cc_false);
break;
case 0x11:
/* MSCPLAY */
case 0x12:
/* MSCPLAY1 */
case 0x13:
/* MSCPLAYR */
{
const cc_u16f track_number = MCDM68kReadWord(user_data, clownmdemu->mcd_m68k->address_registers[0] + 0, target_cycle);
CDDA_SetPlaying(&clownmdemu->state->mega_cd.cdda, cc_true);
CDDA_SetPaused(&clownmdemu->state->mega_cd.cdda, cc_false);
frontend_callbacks->cd_track_seeked((void*)frontend_callbacks->user_data, track_number, command == 0x11 ? CLOWNMDEMU_CDDA_PLAY_ALL : command == 0x12 ? CLOWNMDEMU_CDDA_PLAY_ONCE : CLOWNMDEMU_CDDA_PLAY_REPEAT);
break;
}
case 0x17:
{
/* ROMREAD */
const cc_u32f starting_sector = MCDM68kReadLongword(user_data, clownmdemu->mcd_m68k->address_registers[0] + 0, target_cycle);
ROMSEEK(clownmdemu, frontend_callbacks, starting_sector, 0);
CDCSTART(clownmdemu, frontend_callbacks);
}
case 0x18:
{
/* ROMSEEK */
const cc_u32f starting_sector = MCDM68kReadLongword(user_data, clownmdemu->mcd_m68k->address_registers[0] + 0, target_cycle);
ROMSEEK(clownmdemu, frontend_callbacks, starting_sector, 0);
break;
}
case 0x20:
{
/* ROMREADN */
const cc_u32f starting_sector = MCDM68kReadLongword(user_data, clownmdemu->mcd_m68k->address_registers[0] + 0, target_cycle);
const cc_u32f total_sectors = MCDM68kReadLongword(user_data, clownmdemu->mcd_m68k->address_registers[0] + 4, target_cycle);
/* TODO: What does 0 total sectors do to a real BIOS? */
ROMSEEK(clownmdemu, frontend_callbacks, starting_sector, total_sectors);
CDCSTART(clownmdemu, frontend_callbacks);
break;
}
case 0x21:
{
/* ROMREADE */
const cc_u32f starting_sector = MCDM68kReadLongword(user_data, clownmdemu->mcd_m68k->address_registers[0] + 0, target_cycle);
const cc_u32f last_sector = MCDM68kReadLongword(user_data, clownmdemu->mcd_m68k->address_registers[0] + 4, target_cycle);
/* TODO: How does the official BIOS respond to a negative sector count? */
ROMSEEK(clownmdemu, frontend_callbacks, starting_sector, last_sector < starting_sector ? 0 : last_sector - starting_sector);
CDCSTART(clownmdemu, frontend_callbacks);
break;
}
case 0x85:
{
/* FDRSET */
const cc_bool is_master_volume = (clownmdemu->mcd_m68k->data_registers[1] & 0x8000) != 0;
const cc_u16f volume = clownmdemu->mcd_m68k->data_registers[1] & 0x7FFF;
if (is_master_volume)
CDDA_SetMasterVolume(&clownmdemu->state->mega_cd.cdda, volume);
else
CDDA_SetVolume(&clownmdemu->state->mega_cd.cdda, volume);
break;
}
case 0x86:
{
/* FDRCHG */
const cc_u16f target_volume = clownmdemu->mcd_m68k->data_registers[1] >> 16;
const cc_u16f fade_step = clownmdemu->mcd_m68k->data_registers[1] & 0xFFFF;
CDDA_FadeToVolume(&clownmdemu->state->mega_cd.cdda, target_volume, fade_step);
break;
}
case 0x88:
/* CDCSTART */
CDCSTART(clownmdemu, frontend_callbacks);
break;
case 0x89:
/* CDCSTOP */
CDC_Stop(&clownmdemu->state->mega_cd.cdc);
break;
case 0x8A:
/* CDCSTAT */
if (!CDC_Stat(&clownmdemu->state->mega_cd.cdc, frontend_callbacks->cd_sector_read, frontend_callbacks->user_data))
clownmdemu->mcd_m68k->status_register |= 1; /* Set carry flag to signal that a sector is not ready. */
else
clownmdemu->mcd_m68k->status_register &= ~1; /* Clear carry flag to signal that there's a sector ready. */
break;
case 0x8B:
/* CDCREAD */
if (!CDC_Read(&clownmdemu->state->mega_cd.cdc, frontend_callbacks->cd_sector_read, frontend_callbacks->user_data, &clownmdemu->mcd_m68k->data_registers[0]))
{
/* Sonic Megamix 4.0b relies on this. */
clownmdemu->mcd_m68k->status_register |= 1; /* Set carry flag to signal that a sector has not been prepared. */
}
else
{
/* TODO: This really belongs in the CDC logic, but it needs access to the RAM buffers... */
switch (clownmdemu->state->mega_cd.cdc.device_destination)
{
case CDC_DESTINATION_PCM_RAM:
case CDC_DESTINATION_PRG_RAM:
case CDC_DESTINATION_WORD_RAM:
{
/* TODO: How is RAM address overflow handled? */
cc_u32f address;
const cc_u32f offset = (cc_u32f)clownmdemu->state->mega_cd.cdc.dma_address * 8;
switch (clownmdemu->state->mega_cd.cdc.device_destination)
{
case 4:
address = 0xFFFF2000 + (offset & 0x1FFF);
break;
case 5:
address = 0 + (offset & 0x7FFFF);
break;
case 7:
address = clownmdemu->state->mega_cd.word_ram.in_1m_mode ? 0xC0000 + (offset & 0x1FFFF) : 0x80000 + (offset & 0x3FFFF);
break;
}
/* Discard the header data. */
CDC_HostData(&clownmdemu->state->mega_cd.cdc, cc_true);
CDC_HostData(&clownmdemu->state->mega_cd.cdc, cc_true);
/* Copy the sector data to the DMA destination. */
/* The behaviour of CDC-to-PCM DMA exposes that this really does leverage the Sub-CPU bus on a Mega CD:
the DMA destination address is measured in Sub-CPU address space bytes, not PCM RAM buffer bytes.
That is to say, setting it to 8 will cause the data to be copied to 4 bytes into PCM RAM. */
while ((CDC_Mode(&clownmdemu->state->mega_cd.cdc, cc_true) & 0x4000) != 0)
{
const cc_u16f word = CDC_HostData(&clownmdemu->state->mega_cd.cdc, cc_true);
if (clownmdemu->state->mega_cd.cdc.device_destination == CDC_DESTINATION_PCM_RAM)
{
MCDM68kWriteWord(user_data, address, word >> 8, target_cycle);
address += 2;
MCDM68kWriteWord(user_data, address, word & 0xFF, target_cycle);
}
else
{
MCDM68kWriteWord(user_data, address, word, target_cycle);
}
address += 2;
}
break;
}
}
clownmdemu->mcd_m68k->status_register &= ~1; /* Clear carry flag to signal that a sector has been prepared. */
}
break;
case 0x8C:
/* CDCTRN */
if ((CDC_Mode(&clownmdemu->state->mega_cd.cdc, cc_true) & 0x8000) != 0)
{
clownmdemu->mcd_m68k->status_register |= 1; /* Set carry flag to signal that there's not a sector ready. */
}
else
{
cc_u32f i;
const cc_u32f sector_address = clownmdemu->mcd_m68k->address_registers[0];
const cc_u32f header_address = clownmdemu->mcd_m68k->address_registers[1];
MCDM68kWriteWord(user_data, header_address + 0, CDC_HostData(&clownmdemu->state->mega_cd.cdc, cc_true), target_cycle);
MCDM68kWriteWord(user_data, header_address + 2, CDC_HostData(&clownmdemu->state->mega_cd.cdc, cc_true), target_cycle);
for (i = 0; i < CDC_SECTOR_SIZE; i += 2)
MCDM68kWriteWord(user_data, sector_address + i, CDC_HostData(&clownmdemu->state->mega_cd.cdc, cc_true), target_cycle);
clownmdemu->mcd_m68k->address_registers[0] = (clownmdemu->mcd_m68k->address_registers[0] + CDC_SECTOR_SIZE) & 0xFFFFFFFF;
clownmdemu->mcd_m68k->address_registers[1] = (clownmdemu->mcd_m68k->address_registers[1] + 4) & 0xFFFFFFFF;
clownmdemu->mcd_m68k->status_register &= ~1; /* Clear carry flag to signal that there's always a sector ready. */
}
break;
case 0x8D:
/* CDCACK */
CDC_Ack(&clownmdemu->state->mega_cd.cdc);
break;
default:
LogMessage("UNRECOGNISED BIOS CALL DETECTED (0x%02" CC_PRIXFAST16 ")", command);
break;
}
}
static cc_u16f SyncMCDM68kForRealCallback(const ClownMDEmu* const clownmdemu, void* const user_data)
{
const Clown68000_ReadWriteCallbacks* const m68k_read_write_callbacks = (const Clown68000_ReadWriteCallbacks*)user_data;
return CLOWNMDEMU_MCD_M68K_CLOCK_DIVIDER * Clown68000_DoCycle(clownmdemu->mcd_m68k, m68k_read_write_callbacks);
}
void SyncMCDM68kForReal(const ClownMDEmu* const clownmdemu, const Clown68000_ReadWriteCallbacks* const m68k_read_write_callbacks, const CycleMegaCD target_cycle)
{
const cc_bool mcd_m68k_not_running = clownmdemu->state->mega_cd.m68k.bus_requested || clownmdemu->state->mega_cd.m68k.reset_held;
CPUCallbackUserData* const other_state = (CPUCallbackUserData*)m68k_read_write_callbacks->user_data;
SyncCPUCommon(clownmdemu, &other_state->sync.mcd_m68k, target_cycle.cycle, mcd_m68k_not_running, SyncMCDM68kForRealCallback, m68k_read_write_callbacks);
}
static cc_u16f SyncMCDM68kCallback(const ClownMDEmu* const clownmdemu, void* const user_data)
{
const Clown68000_ReadWriteCallbacks* const m68k_read_write_callbacks = (const Clown68000_ReadWriteCallbacks*)user_data;
CPUCallbackUserData* const other_state = (CPUCallbackUserData*)m68k_read_write_callbacks->user_data;
CycleMegaCD current_cycle;
/* Update the 68000 to this point in time. */
current_cycle.cycle = other_state->sync.mcd_m68k_irq3.current_cycle;
SyncMCDM68kForReal(clownmdemu, m68k_read_write_callbacks, current_cycle);
/* Raise an interrupt. */
if (clownmdemu->state->mega_cd.irq.enabled[2])
Clown68000_Interrupt(clownmdemu->mcd_m68k, 3);
return clownmdemu->state->mega_cd.irq.irq3_countdown_master;
}
void SyncMCDM68k(const ClownMDEmu* const clownmdemu, CPUCallbackUserData* const other_state, const CycleMegaCD target_cycle)
{
Clown68000_ReadWriteCallbacks m68k_read_write_callbacks;
m68k_read_write_callbacks.read_callback = MCDM68kReadCallback;
m68k_read_write_callbacks.write_callback = MCDM68kWriteCallback;
m68k_read_write_callbacks.user_data = other_state;
/* In order to support the timer interrupt (IRQ3), we hijack this function to update an IRQ3 sync object instead. */
/* This sync object will raise interrupts whilst also synchronising the 68000. */
SyncCPUCommon(clownmdemu, &other_state->sync.mcd_m68k_irq3, target_cycle.cycle, cc_false, SyncMCDM68kCallback, &m68k_read_write_callbacks);
/* Now that we're done with IRQ3, finish synchronising the 68000. */
SyncMCDM68kForReal(clownmdemu, &m68k_read_write_callbacks, target_cycle);
}
static size_t StampMapDiameterInPixels(ClownMDEmu_State* const state)
{
return state->mega_cd.rotation.large_stamp_map ? 1 << 12 : 1 << 8;
}
#define SHIFT_TO_NORMAL(SHIFT) ((size_t)1 << (SHIFT))
#define BITS_PER_PIXEL 4
#define BITS_PER_BYTE 8
#define BITS_PER_WORD 16
#define PIXELS_PER_BYTE (BITS_PER_BYTE / BITS_PER_PIXEL)
#define PIXELS_PER_WORD (BITS_PER_WORD / BITS_PER_PIXEL)
#define STAMP_TILE_DIAMETER_IN_PIXELS_SHIFT 3
#define STAMP_TILE_DIAMETER_IN_PIXELS SHIFT_TO_NORMAL(STAMP_TILE_DIAMETER_IN_PIXELS_SHIFT)
static cc_u8f StampDiameterInPixelsShift(ClownMDEmu_State* const state)
{
return STAMP_TILE_DIAMETER_IN_PIXELS_SHIFT + 1 + state->mega_cd.rotation.large_stamp;
}
static const cc_u16l* GetStampMapAddress(ClownMDEmu_State* const state)
{
return state->mega_cd.word_ram.buffer + (size_t)state->mega_cd.rotation.stamp_map_address * 2;
}
#define SMALL_STAMP_DIAMETER_IN_PIXELS_SHIFT (STAMP_TILE_DIAMETER_IN_PIXELS_SHIFT + 1) /* 16x16 */
#define SMALL_STAMP_DIAMETER_IN_PIXELS SHIFT_TO_NORMAL(SMALL_STAMP_DIAMETER_IN_PIXELS_SHIFT)
#define LARGE_STAMP_DIAMETER_IN_PIXELS_SHIFT (STAMP_TILE_DIAMETER_IN_PIXELS_SHIFT + 2) /* 32x32 */
#define LARGE_STAMP_DIAMETER_IN_PIXELS SHIFT_TO_NORMAL(LARGE_STAMP_DIAMETER_IN_PIXELS_SHIFT)
#define SMALL_STAMP_SIZE_IN_WORDS (SMALL_STAMP_DIAMETER_IN_PIXELS * SMALL_STAMP_DIAMETER_IN_PIXELS / PIXELS_PER_WORD)
#define LARGE_STAMP_SIZE_IN_WORDS (LARGE_STAMP_DIAMETER_IN_PIXELS * LARGE_STAMP_DIAMETER_IN_PIXELS / PIXELS_PER_WORD)
static const cc_u16l* GetStampAddress(ClownMDEmu_State* const state, const cc_u16f index)
{
if (state->mega_cd.rotation.large_stamp)
return state->mega_cd.word_ram.buffer + (index * SMALL_STAMP_SIZE_IN_WORDS);
else
return state->mega_cd.word_ram.buffer + (index / (LARGE_STAMP_SIZE_IN_WORDS / SMALL_STAMP_SIZE_IN_WORDS) * LARGE_STAMP_SIZE_IN_WORDS);
}
static size_t PixelIndexFromImageBufferCoordinate(const cc_u16f x, const cc_u16f y, const size_t image_buffer_height)
{
const cc_u16f pixel_x_in_tile = x % STAMP_TILE_DIAMETER_IN_PIXELS;
const cc_u8f tile_x_in_image_buffer = x / STAMP_TILE_DIAMETER_IN_PIXELS;
const size_t tile_row_index = (size_t)tile_x_in_image_buffer * image_buffer_height + y;
return (size_t)tile_row_index * STAMP_TILE_DIAMETER_IN_PIXELS + pixel_x_in_tile;
}
static cc_u8f ReadPixelFromWord(const cc_u16f word, const cc_u8f pixel_index)
{
const cc_u8f pixel_mask = ((1 << BITS_PER_PIXEL) - 1);
return (word >> (BITS_PER_WORD - (BITS_PER_PIXEL * (1 + pixel_index)))) & pixel_mask;
}
static void WritePixelToWord(cc_u16l* const word, const cc_u8f pixel_index, const cc_u8f pixel)
{
const cc_u16f pixel_mask = ((1 << BITS_PER_PIXEL) - 1);
const cc_u8f shift = (BITS_PER_WORD - (BITS_PER_PIXEL * (1 + pixel_index)));
*word &= ~(pixel_mask << shift);
*word |= (cc_u16f)pixel << shift;
}
static cc_u8f PixelFromStamp(const cc_u16l* const buffer, const cc_u16f x, const cc_u16f y, const size_t stamp_height)
{
const cc_u32f pixel_index_within_stamp = PixelIndexFromImageBufferCoordinate(x, y, stamp_height);
const cc_u32f word_index_within_stamp = pixel_index_within_stamp / PIXELS_PER_WORD;
const cc_u8f pixel_index_within_word = pixel_index_within_stamp % PIXELS_PER_WORD;
const cc_u16f word = buffer[word_index_within_stamp];
const cc_u8f pixel = ReadPixelFromWord(word, pixel_index_within_word);
return pixel;
}
static cc_u8f ReadPixelFromStampMap(ClownMDEmu_State* const state, const cc_u32f x, const cc_u32f y)
{
const cc_u8f stamp_diameter_in_pixels_shift = StampDiameterInPixelsShift(state);
const size_t stamp_diameter_in_pixels = SHIFT_TO_NORMAL(stamp_diameter_in_pixels_shift);
const size_t stamp_map_diameter_in_pixels = StampMapDiameterInPixels(state);
const size_t stamp_map_diameter_in_stamps = stamp_map_diameter_in_pixels >> stamp_diameter_in_pixels_shift;
const size_t stamp_map_size_mask = stamp_map_diameter_in_pixels - 1;
const size_t stamp_size_mask = stamp_diameter_in_pixels - 1;
if (!state->mega_cd.rotation.repeating_stamp_map && (x >= stamp_map_diameter_in_pixels || y >= stamp_map_diameter_in_pixels))
{
return 0;
}
else
{
const size_t pixel_x_within_stamp_map = x & stamp_map_size_mask;
const size_t pixel_y_within_stamp_map = y & stamp_map_size_mask;
const size_t stamp_x_within_stamp_map = pixel_x_within_stamp_map >> stamp_diameter_in_pixels_shift;
const size_t stamp_y_within_stamp_map = pixel_y_within_stamp_map >> stamp_diameter_in_pixels_shift;
const size_t stamp_index_within_stamp_map = stamp_y_within_stamp_map * stamp_map_diameter_in_stamps + stamp_x_within_stamp_map;
const cc_u16f stamp_metadata = GetStampMapAddress(state)[stamp_index_within_stamp_map];
const cc_u16f stamp_index = stamp_metadata & 0x7FF;
const cc_u8f rotation = (stamp_metadata >> 13) & 3;
const cc_bool horizontal_flip = (stamp_metadata & 0x8000) != 0;
if (stamp_index == 0)
{
return 0;
}
else
{
const cc_u16l* const stamp_address = GetStampAddress(state, stamp_index);
cc_u16f pixel_x_within_stamp = pixel_x_within_stamp_map & stamp_size_mask;
cc_u16f pixel_y_within_stamp = pixel_y_within_stamp_map & stamp_size_mask;
cc_bool x_flip = cc_false, y_flip = cc_false, swap_coordinates = cc_false;
switch (rotation)
{
case 0: /* 0 degrees */
break;
case 1: /* 90 degrees */
y_flip = cc_true;
swap_coordinates = cc_true;
break;
case 2: /* 180 degrees */
x_flip = cc_true;
y_flip = cc_true;
break;
case 3: /* 270 degrees */
x_flip = cc_true;
swap_coordinates = cc_true;
break;
}
x_flip ^= horizontal_flip;
if (x_flip)
pixel_x_within_stamp = stamp_diameter_in_pixels - pixel_x_within_stamp - 1;
if (y_flip)
pixel_y_within_stamp = stamp_diameter_in_pixels - pixel_y_within_stamp - 1;
return PixelFromStamp(stamp_address, swap_coordinates ? pixel_y_within_stamp : pixel_x_within_stamp, swap_coordinates ? pixel_x_within_stamp : pixel_y_within_stamp, stamp_diameter_in_pixels);
}
}
}
#define FILE_NAME_LENGTH 11
#define FILE_NAME_BUFFER_LENGTH (FILE_NAME_LENGTH + 1 + 2 + 1 + 3 + 1)
static void ReadFilename(const void* const user_data, char* const file_name_buffer, const cc_bool write_protected, const CycleMegaCD target_cycle)
{
CPUCallbackUserData* const callback_user_data = (CPUCallbackUserData*)user_data;
const ClownMDEmu* const clownmdemu = callback_user_data->clownmdemu;
char *file_name_pointer = file_name_buffer;
cc_u8f i;
for (i = 0; i < FILE_NAME_LENGTH; ++i)
*file_name_pointer++ = MCDM68kReadByte(user_data, clownmdemu->mcd_m68k->address_registers[0] + i, target_cycle);
if (write_protected)
{
*file_name_pointer++ = '.';
*file_name_pointer++ = 'w';
*file_name_pointer++ = 'p';
}
*file_name_pointer++ = '.';
*file_name_pointer++ = 'b';
*file_name_pointer++ = 'r';
*file_name_pointer++ = 'm';
*file_name_pointer++ = '\0';
}
static cc_bool OpenSaveFileForReading(const void* const user_data, const cc_bool write_protected, const CycleMegaCD target_cycle)
{
CPUCallbackUserData* const callback_user_data = (CPUCallbackUserData*)user_data;
const ClownMDEmu* const clownmdemu = callback_user_data->clownmdemu;
char file_name_buffer[FILE_NAME_BUFFER_LENGTH];
ReadFilename(user_data, file_name_buffer, write_protected, target_cycle);
return clownmdemu->callbacks->save_file_opened_for_reading((void*)clownmdemu->callbacks->user_data, file_name_buffer);
}
static cc_bool OpenSaveFileForReadingAny(const void* const user_data, cc_bool* const write_protected, const CycleMegaCD target_cycle)
{
if (OpenSaveFileForReading(user_data, cc_false, target_cycle))
{
*write_protected = cc_false;
return cc_true;
}
if (OpenSaveFileForReading(user_data, cc_true, target_cycle))
{
*write_protected = cc_true;
return cc_true;
}
return cc_false;
}
static cc_bool OpenSaveFileForWriting(const void* const user_data, const cc_bool write_protected, const CycleMegaCD target_cycle)
{
CPUCallbackUserData* const callback_user_data = (CPUCallbackUserData*)user_data;
const ClownMDEmu* const clownmdemu = callback_user_data->clownmdemu;
char file_name_buffer[FILE_NAME_BUFFER_LENGTH];
ReadFilename(user_data, file_name_buffer, write_protected, target_cycle);
return clownmdemu->callbacks->save_file_opened_for_writing((void*)clownmdemu->callbacks->user_data, file_name_buffer);
}
static cc_bool RemoveSaveFile(const void* const user_data, const cc_bool write_protected, const CycleMegaCD target_cycle)
{
CPUCallbackUserData* const callback_user_data = (CPUCallbackUserData*)user_data;
const ClownMDEmu* const clownmdemu = callback_user_data->clownmdemu;
char file_name_buffer[FILE_NAME_BUFFER_LENGTH];
ReadFilename(user_data, file_name_buffer, write_protected, target_cycle);
return clownmdemu->callbacks->save_file_removed((void*)clownmdemu->callbacks->user_data, file_name_buffer);
}
static cc_bool RemoveSaveFileAny(const void* const user_data, const CycleMegaCD target_cycle)
{
cc_bool success = cc_false;
success |= RemoveSaveFile(user_data, cc_false, target_cycle);
success |= RemoveSaveFile(user_data, cc_true, target_cycle);
return success;
}
static cc_bool GetSaveFileSize(const void* const user_data, const cc_bool write_protected, size_t* const file_size, const CycleMegaCD target_cycle)
{
CPUCallbackUserData* const callback_user_data = (CPUCallbackUserData*)user_data;
const ClownMDEmu* const clownmdemu = callback_user_data->clownmdemu;
char file_name_buffer[FILE_NAME_BUFFER_LENGTH];
ReadFilename(user_data, file_name_buffer, write_protected, target_cycle);
return clownmdemu->callbacks->save_file_size_obtained((void*)clownmdemu->callbacks->user_data, file_name_buffer, file_size);
}
static cc_bool GetSaveFileSizeAny(const void* const user_data, cc_bool* const write_protected, size_t* const file_size, const CycleMegaCD target_cycle)
{
if (GetSaveFileSize(user_data, cc_false, file_size, target_cycle))
{
*write_protected = cc_false;
return cc_true;
}
if (GetSaveFileSize(user_data, cc_true, file_size, target_cycle))
{
*write_protected = cc_true;
return cc_true;
}
return cc_false;
}
#define BURAM_BLOCK_SIZE(WRITE_PROTECTED) ((WRITE_PROTECTED) ? 0x20 : 0x40)
cc_u16f MCDM68kReadCallbackWithCycle(const void* const user_data, const cc_u32f address_word, const cc_bool do_high_byte, const cc_bool do_low_byte, const CycleMegaCD target_cycle)
{
CPUCallbackUserData* const callback_user_data = (CPUCallbackUserData*)user_data;
const ClownMDEmu* const clownmdemu = callback_user_data->clownmdemu;
const ClownMDEmu_Callbacks* const frontend_callbacks = clownmdemu->callbacks;
const cc_u32f address = address_word * 2;
cc_u16f value = 0;
(void)do_high_byte;
(void)do_low_byte;
if (/*address >= 0 &&*/ address < 0x80000)
{
/* PRG-RAM */
if (address == 0x5F16 && clownmdemu->mcd_m68k->program_counter == 0x5F16)
{
/* BRAM call! */
/* TODO: None of this shit is accurate at all. */
const cc_u16f command = clownmdemu->mcd_m68k->data_registers[0] & 0xFFFF;
switch (command)
{
case 0x00:
/* BRMINIT */
clownmdemu->mcd_m68k->status_register &= ~1; /* Formatted RAM is present. */
/* Size of Backup RAM. */
clownmdemu->mcd_m68k->data_registers[0] &= 0xFFFF0000;
clownmdemu->mcd_m68k->data_registers[0] |= 0x100; /* Maximum officially-allowed size. */
/* "Display strings". */
/*clownmdemu->mcd_m68k->address_registers[1] = I have no idea; */
break;
case 0x01:
/* BRMSTAT */
/* TODO: Report more files. */
clownmdemu->mcd_m68k->data_registers[0] &= 0xFFFF0000;
clownmdemu->mcd_m68k->data_registers[0] |= 100; /* 100 free blocks. */
clownmdemu->mcd_m68k->data_registers[1] &= 0xFFFF0000;
clownmdemu->mcd_m68k->data_registers[1] |= 1; /* Just one file. */
break;
case 0x02:
{
/* BRMSERCH */
cc_bool write_protected;
size_t file_size;
if (!GetSaveFileSizeAny(user_data, &write_protected, &file_size, target_cycle))
{
clownmdemu->mcd_m68k->status_register |= 1; /* File not found. */
}
else
{
clownmdemu->mcd_m68k->data_registers[0] &= 0xFFFF0000;
clownmdemu->mcd_m68k->data_registers[0] |= (file_size / BURAM_BLOCK_SIZE(write_protected)) & 0xFFFF;
clownmdemu->mcd_m68k->data_registers[1] &= 0xFFFFFF00;
clownmdemu->mcd_m68k->data_registers[1] |= write_protected ? 0xFF : 0;
clownmdemu->mcd_m68k->status_register &= ~1; /* File found. */
}
break;
}
case 0x03:
{
/* BRMREAD */
cc_bool write_protected;
if (!OpenSaveFileForReadingAny(user_data, &write_protected, target_cycle))
{
clownmdemu->mcd_m68k->status_register |= 1; /* Error. */
}
else
{
cc_u32f total_bytes = 0;
cc_s16f value;
while ((value = frontend_callbacks->save_file_read((void*)frontend_callbacks->user_data)) != -1)
MCDM68kWriteByte(user_data, clownmdemu->mcd_m68k->address_registers[1] + total_bytes++, value, target_cycle);
frontend_callbacks->save_file_closed((void*)frontend_callbacks->user_data);
clownmdemu->mcd_m68k->data_registers[0] &= 0xFFFF0000;
clownmdemu->mcd_m68k->data_registers[0] |= (total_bytes / BURAM_BLOCK_SIZE(write_protected)) & 0xFFFF;
clownmdemu->mcd_m68k->data_registers[1] &= 0xFFFFFF00;
clownmdemu->mcd_m68k->data_registers[1] |= write_protected ? 0xFF : 0;
clownmdemu->mcd_m68k->status_register &= ~1; /* Okay */
}
break;
}
case 0x04:
{
/* BRMWRITE */
const cc_bool write_protected = MCDM68kReadByte(user_data, clownmdemu->mcd_m68k->address_registers[0] + FILE_NAME_LENGTH, target_cycle) != 0;
if (!OpenSaveFileForWriting(user_data, write_protected, target_cycle))
{
clownmdemu->mcd_m68k->status_register |= 1; /* Error. */
}
else
{
const cc_u16f total_blocks = MCDM68kReadWord(user_data, clownmdemu->mcd_m68k->address_registers[0] + FILE_NAME_LENGTH + 1, target_cycle);
const cc_u32f total_bytes = (cc_u32f)total_blocks * BURAM_BLOCK_SIZE(write_protected);
cc_u32f i;
for (i = 0; i < total_bytes; ++i)
frontend_callbacks->save_file_written((void*)frontend_callbacks->user_data, MCDM68kReadByte(user_data, clownmdemu->mcd_m68k->address_registers[1] + i, target_cycle));
frontend_callbacks->save_file_closed((void*)frontend_callbacks->user_data);
clownmdemu->mcd_m68k->status_register &= ~1; /* Okay */
}
break;
}
case 0x05:
/* BRMDEL */
if (!RemoveSaveFileAny(user_data, target_cycle))
clownmdemu->mcd_m68k->status_register |= 1; /* Error */
else
clownmdemu->mcd_m68k->status_register &= ~1; /* Okay */
break;
case 0x06:
/* BRMFORMAT */
/* TODO: Delete everything? */
clownmdemu->mcd_m68k->status_register &= ~1; /* Okay */
break;
case 0x07:
/* BRMDIR */
/* TODO: Implement this. */
clownmdemu->mcd_m68k->status_register |= 1; /* Error. */
break;
case 0x08:
{
/* BRMVERIFY */
const cc_bool write_protected = MCDM68kReadByte(user_data, clownmdemu->mcd_m68k->address_registers[0] + FILE_NAME_LENGTH, target_cycle) != 0;
if (!OpenSaveFileForReading(user_data, write_protected, target_cycle))
{
clownmdemu->mcd_m68k->status_register |= 1; /* Error. */
}
else
{
/* TODO: Signal an error if the file is longer than expected? */
const cc_u16f total_blocks = MCDM68kReadWord(user_data, clownmdemu->mcd_m68k->address_registers[0] + FILE_NAME_LENGTH + 1, target_cycle);
const cc_u32f total_bytes = (cc_u32f)total_blocks * BURAM_BLOCK_SIZE(write_protected);
cc_u32f i;
for (i = 0; i < total_bytes; ++i)
{
const cc_u8f source_value = MCDM68kReadByte(user_data, clownmdemu->mcd_m68k->address_registers[1] + i, target_cycle);
const cc_s16f destination_value = frontend_callbacks->save_file_read((void*)frontend_callbacks->user_data);
/* End of file encountered too early, or mismatch. */
if (destination_value == -1 || (cc_u16f)destination_value != source_value)
break;
}
frontend_callbacks->save_file_closed((void*)frontend_callbacks->user_data);
if (i != total_bytes)
clownmdemu->mcd_m68k->status_register |= 1; /* Error. */
else
clownmdemu->mcd_m68k->status_register &= ~1; /* Okay. */
}
break;
}
default:
LogMessage("UNRECOGNISED BRAM CALL DETECTED (0x%02" CC_PRIXFAST16 ")", command);
break;
}
value = 0x4E75; /* 'rts' instruction */
}
else if (address == 0x5F22 && clownmdemu->mcd_m68k->program_counter == 0x5F22)
{
/* BIOS call! */
MegaCDBIOSCall(clownmdemu, user_data, frontend_callbacks, target_cycle);
value = 0x4E75; /* 'rts' instruction */
}
else
{
value = clownmdemu->state->mega_cd.prg_ram.buffer[address_word];
}
}
else if (address < 0xC0000)
{
/* WORD-RAM */
if (clownmdemu->state->mega_cd.word_ram.in_1m_mode)
{
/* TODO. */
LogMessage("SUB-CPU attempted to read from the weird half of 1M WORD-RAM at 0x%" CC_PRIXLEAST32, clownmdemu->state->mega_cd.m68k.state.program_counter);
}
else if (!clownmdemu->state->mega_cd.word_ram.dmna)
{
/* TODO: According to Page 24 of MEGA-CD HARDWARE MANUAL, this should cause the CPU to hang, just like the Z80 accessing the ROM during a DMA transfer. */
LogMessage("SUB-CPU attempted to read from WORD-RAM while MAIN-CPU has it at 0x%" CC_PRIXLEAST32, clownmdemu->state->mega_cd.m68k.state.program_counter);
}
else
{
value = clownmdemu->state->mega_cd.word_ram.buffer[address_word % CC_COUNT_OF(clownmdemu->state->mega_cd.word_ram.buffer)];
}
}
else if (address < 0xE0000)
{
/* WORD-RAM */
if (!clownmdemu->state->mega_cd.word_ram.in_1m_mode)
{
/* TODO. */
LogMessage("SUB-CPU attempted to read from the 1M half of WORD-RAM in 2M mode at 0x%" CC_PRIXLEAST32, clownmdemu->state->mega_cd.m68k.state.program_counter);
}
else
{
value = clownmdemu->state->mega_cd.word_ram.buffer[(address_word * 2 + !clownmdemu->state->mega_cd.word_ram.ret) % CC_COUNT_OF(clownmdemu->state->mega_cd.word_ram.buffer)];
}
}
else if (address >= 0xFF0000 && address < 0xFF8000)
{
const cc_u16f masked_address = address_word & 0xFFF;
if ((address & 0x2000) != 0)
{
/* PCM wave RAM */
value = PCM_ReadWaveRAM(&clownmdemu->pcm, masked_address);
}
else
{
/* PCM register */
SyncPCM(callback_user_data, target_cycle);
value = PCM_ReadRegister(&clownmdemu->pcm, masked_address);
}
}
else if (address == 0xFF8000)
{
/* Reset */
/* TODO: Everything else here. */
value = 1; /* Signal that the Mega CD is ready. */
}
else if (address == 0xFF8002)
{
/* Memory mode / Write protect */
value = ((cc_u16f)clownmdemu->state->mega_cd.prg_ram.write_protect << 8) | ((cc_u16f)clownmdemu->state->mega_cd.word_ram.in_1m_mode << 2) | ((cc_u16f)clownmdemu->state->mega_cd.word_ram.dmna << 1) | ((cc_u16f)clownmdemu->state->mega_cd.word_ram.ret << 0);
}
else if (address == 0xFF8004)
{
/* CDC mode / device destination */
value = CDC_Mode(&clownmdemu->state->mega_cd.cdc, cc_true);
}
else if (address == 0xFF8006)
{
/* H-INT vector */
LogMessage("SUB-CPU attempted to read from H-INT vector register at 0x%" CC_PRIXLEAST32, clownmdemu->mcd_m68k->program_counter);
}
else if (address == 0xFF8008)
{
/* CDC host data */
value = CDC_HostData(&clownmdemu->state->mega_cd.cdc, cc_true);
}
else if (address == 0xFF800A)
{
/* CDC DMA address */
LogMessage("SUB-CPU attempted to read from DMA address register at 0x%" CC_PRIXLEAST32, clownmdemu->mcd_m68k->program_counter);
}
else if (address == 0xFF800C)
{
/* Stop watch */
LogMessage("SUB-CPU attempted to read from stop watch register at 0x%" CC_PRIXLEAST32, clownmdemu->mcd_m68k->program_counter);
}
else if (address == 0xFF800E)
{
/* Communication flag */
SyncM68k(clownmdemu, callback_user_data, CycleMegaCDToMegaDrive(clownmdemu, target_cycle));
value = clownmdemu->state->mega_cd.communication.flag;
}
else if (address >= 0xFF8010 && address < 0xFF8020)
{
/* Communication command */
SyncM68k(clownmdemu, callback_user_data, CycleMegaCDToMegaDrive(clownmdemu, target_cycle));
value = clownmdemu->state->mega_cd.communication.command[(address - 0xFF8010) / 2];
}
else if (address >= 0xFF8020 && address < 0xFF8030)
{
/* Communication status */
SyncM68k(clownmdemu, callback_user_data, CycleMegaCDToMegaDrive(clownmdemu, target_cycle));
value = clownmdemu->state->mega_cd.communication.status[(address - 0xFF8020) / 2];
}
else if (address == 0xFF8030)
{
/* Timer W/INT3 */
LogMessage("SUB-CPU attempted to read from Timer W/INT3 register at 0x%" CC_PRIXLEAST32, clownmdemu->mcd_m68k->program_counter);
}
else if (address == 0xFF8032)
{
/* Interrupt mask control */
cc_u8f i;
value = 0;
for (i = 0; i < CC_COUNT_OF(clownmdemu->state->mega_cd.irq.enabled); ++i)
value |= (cc_u16f)clownmdemu->state->mega_cd.irq.enabled[i] << (1 + i);
}
else if (address == 0xFF8058)
{
/* Stamp data size */
value = clownmdemu->state->mega_cd.rotation.large_stamp_map << 2 | clownmdemu->state->mega_cd.rotation.large_stamp << 1 | clownmdemu->state->mega_cd.rotation.repeating_stamp_map << 0;
}
else if (address == 0xFF805A)
{
/* Stamp map base address */
value = clownmdemu->state->mega_cd.rotation.stamp_map_address;
}
else if (address == 0xFF805C)
{
/* Image buffer vertical cell size */
value = clownmdemu->state->mega_cd.rotation.image_buffer_height_in_tiles;
}
else if (address == 0xFF805E)
{
/* Image buffer base address */
value = clownmdemu->state->mega_cd.rotation.image_buffer_address;
}
else if (address == 0xFF8060)
{
/* Image buffer offset */
value = clownmdemu->state->mega_cd.rotation.image_buffer_y_offset << 3 | clownmdemu->state->mega_cd.rotation.image_buffer_x_offset << 0;
}
else if (address == 0xFF8062)
{
/* Image buffer width */
value = clownmdemu->state->mega_cd.rotation.image_buffer_width;
}
else if (address == 0xFF8064)
{
/* Image buffer height */
value = clownmdemu->state->mega_cd.rotation.image_buffer_height;
}
else if (address == 0xFF8066)
{
/* Trace table address */
LogMessage("Attempted to read trace table address register at 0x%" CC_PRIXLEAST32, clownmdemu->mcd_m68k->program_counter);
}
else
{
LogMessage("Attempted to read invalid MCD 68k address 0x%" CC_PRIXFAST32 " at 0x%" CC_PRIXLEAST32, address, clownmdemu->mcd_m68k->program_counter);
}
return value;
}
cc_u16f MCDM68kReadCallback(const void* const user_data, const cc_u32f address, const cc_bool do_high_byte, const cc_bool do_low_byte)
{
CPUCallbackUserData* const callback_user_data = (CPUCallbackUserData*)user_data;
return MCDM68kReadCallbackWithCycle(user_data, address, do_high_byte, do_low_byte, MakeCycleMegaCD(callback_user_data->sync.mcd_m68k.current_cycle));
}
void MCDM68kWriteCallbackWithCycle(const void* const user_data, const cc_u32f address_word, const cc_bool do_high_byte, const cc_bool do_low_byte, const cc_u16f value, const CycleMegaCD target_cycle)
{
CPUCallbackUserData* const callback_user_data = (CPUCallbackUserData*)user_data;
const ClownMDEmu* const clownmdemu = callback_user_data->clownmdemu;
const cc_u32f address = address_word * 2;
const cc_u16f high_byte = (value >> 8) & 0xFF;
const cc_u16f low_byte = (value >> 0) & 0xFF;
cc_u16f mask = 0;
if (do_high_byte)
mask |= 0xFF00;
if (do_low_byte)
mask |= 0x00FF;
if (/*address >= 0 &&*/ address < 0x80000)
{
/* PRG-RAM */
if (address < (cc_u32f)clownmdemu->state->mega_cd.prg_ram.write_protect * 0x200)