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changeset 1502:2564b6ba2e12 segacd

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Initial skeleton of Sega CD memory handlers
author Michael Pavone <pavone@retrodev.com>
date Tue, 12 Dec 2017 09:44:33 -0800
parents d2d637dbacfb
children a763523dadf4
files Makefile genesis.h segacd.c segacd.h
diffstat 4 files changed, 283 insertions(+), 1 deletions(-) [+]
line wrap: on
line diff
--- a/Makefile	Sat Oct 21 11:51:24 2017 -0700
+++ b/Makefile	Tue Dec 12 09:44:33 2017 -0800
@@ -127,7 +127,7 @@
 AUDIOOBJS=ym2612.o psg.o wave.o
 CONFIGOBJS=config.o tern.o util.o
 
-MAINOBJS=blastem.o system.o genesis.o debug.o gdb_remote.o vdp.o render_sdl.o ppm.o io.o romdb.o hash.o menu.o xband.o realtec.o i2c.o nor.o sega_mapper.o multi_game.o serialize.o $(TERMINAL) $(CONFIGOBJS) gst.o $(M68KOBJS) $(TRANSOBJS) $(AUDIOOBJS)
+MAINOBJS=blastem.o system.o genesis.o segacd.o debug.o gdb_remote.o vdp.o render_sdl.o ppm.o io.o romdb.o hash.o menu.o xband.o realtec.o i2c.o nor.o sega_mapper.o multi_game.o serialize.o $(TERMINAL) $(CONFIGOBJS) gst.o $(M68KOBJS) $(TRANSOBJS) $(AUDIOOBJS)
 
 ifeq ($(CPU),x86_64)
 CFLAGS+=-DX86_64 -m64
--- a/genesis.h	Sat Oct 21 11:51:24 2017 -0700
+++ b/genesis.h	Tue Dec 12 09:44:33 2017 -0800
@@ -31,6 +31,7 @@
 	uint16_t        *lock_on;
 	uint16_t        *work_ram;
 	uint8_t         *zram;
+	void            *expansion;
 	void            *extra;
 	uint8_t         *save_storage;
 	void            *mapper_temp;
--- a/segacd.c	Sat Oct 21 11:51:24 2017 -0700
+++ b/segacd.c	Tue Dec 12 09:44:33 2017 -0800
@@ -0,0 +1,257 @@
+#include <stdlib.h>
+#include <string.h>
+#include "segacd.h"
+#include "genesis.h"
+#include "util.h"
+
+static void *prog_ram_wp_write16(uint32_t address, void *vcontext, uint16_t value)
+{
+	return vcontext;
+}
+
+static void *prog_ram_wp_write8(uint32_t address, void *vcontext, uint8_t value)
+{
+	return vcontext;
+}
+
+static uint16_t work_ram_2M_read16(uint32_t address, void *vcontext)
+{
+	return 0;
+}
+
+static uint8_t work_ram_2M_read8(uint32_t address, void *vcontext)
+{
+	return 0;
+}
+
+static void *work_ram_2M_write16(uint32_t address, void *vcontext, uint16_t value)
+{
+	return vcontext;
+}
+
+static void *work_ram_2M_write8(uint32_t address, void *vcontext, uint8_t value)
+{
+	return vcontext;
+}
+
+static uint16_t work_ram_1M_read16(uint32_t address, void *vcontext)
+{
+	return 0;
+}
+
+static uint8_t work_ram_1M_read8(uint32_t address, void *vcontext)
+{
+	return 0;
+}
+
+static void *work_ram_1M_write16(uint32_t address, void *vcontext, uint16_t value)
+{
+	return vcontext;
+}
+
+static void *work_ram_1M_write8(uint32_t address, void *vcontext, uint8_t value)
+{
+	return vcontext;
+}
+
+static uint8_t pcm_read8(uint32_t address, void *vcontext)
+{
+	return 0;
+}
+
+static uint16_t pcm_read16(uint32_t address, void *vcontext)
+{
+	return 0xFF00 | pcm_read8(address+1, vcontext);
+}
+
+static void *pcm_write8(uint32_t address, void *vcontext, uint8_t value)
+{
+	return vcontext;
+}
+
+static void *pcm_write16(uint32_t address, void *vcontext, uint16_t value)
+{
+	return pcm_write8(address+1, vcontext, value);
+}
+
+static uint16_t sub_gate_read16(uint32_t address, void *vcontext)
+{
+	m68k_context *m68k = vcontext;
+	segacd_context *cd = m68k->system;
+	return cd->gate_array[(address & 0x1FF) >> 1];
+}
+
+static uint8_t sub_gate_read8(uint32_t address, void *vcontext)
+{
+	m68k_context *m68k = vcontext;
+	segacd_context *cd = m68k->system;
+	uint16_t val = cd->gate_array[(address & 0x1FF) >> 1];
+	return address & 1 ? val : val >> 8;
+}
+
+static void *sub_gate_write16(uint32_t address, void *vcontext, uint16_t value)
+{
+	m68k_context *m68k = vcontext;
+	segacd_context *cd = m68k->system;
+	uint32_t reg = (address & 0x1FF) >> 1;
+	switch (reg)
+	{
+	case 0x7:
+		cd->gate_array[reg] &= 0xFF00;
+		cd->gate_array[reg] |= value & 0xFF;
+		break;
+	case 0x10:
+	case 0x11:
+	case 0x12:
+	case 0x13:
+	case 0x14:
+	case 0x15:
+	case 0x16:
+	case 0x17:
+		//no effects for these other than saving the value
+		cd->gate_array[reg] = value;
+		break;
+	default:
+		printf("Unhandled gate array write %X:%X\n", address, value);
+	}
+	return vcontext;
+}
+
+static void *sub_gate_write8(uint32_t address, void *vcontext, uint8_t value)
+{
+	m68k_context *m68k = vcontext;
+	segacd_context *cd = m68k->system;
+	uint32_t reg = (address & 0x1FF) >> 1;
+	uint16_t value16;
+	if (address & 1) {
+		value16 = cd->gate_array[reg] & 0xFF00 | value;
+	} else {
+		value16 = cd->gate_array[reg] & 0xFF | (value << 8);
+	}
+	return sub_gate_write16(address, vcontext, value16);
+}
+
+static uint16_t main_gate_read16(uint32_t address, void *vcontext)
+{
+	m68k_context *m68k = vcontext;
+	segacd_context *cd = m68k->system;
+	return cd->gate_array[(address & 0x1FF) >> 1];
+}
+
+static uint8_t main_gate_read8(uint32_t address, void *vcontext)
+{
+	m68k_context *m68k = vcontext;
+	segacd_context *cd = m68k->system;
+	uint16_t val = cd->gate_array[(address & 0x1FF) >> 1];
+	return address & 1 ? val : val >> 8;
+}
+
+static void *main_gate_write16(uint32_t address, void *vcontext, uint16_t value)
+{
+	m68k_context *m68k = vcontext;
+	genesis_context *gen = m68k->system;
+	segacd_context *cd = gen->expansion;
+	uint32_t reg = (address & 0x1FF) >> 1;
+	switch (reg)
+	{
+	case 0x7:
+		cd->gate_array[reg] &= 0xFF;
+		cd->gate_array[reg] |= value & 0xFF00;
+		break;
+	case 0x8:
+	case 0x9:
+	case 0xA:
+	case 0xB:
+	case 0xC:
+	case 0xD:
+	case 0xE:
+	case 0xF:
+		//no effects for these other than saving the value
+		cd->gate_array[reg] = value;
+		break;
+	default:
+		printf("Unhandled gate array write %X:%X\n", address, value);
+	}
+	return vcontext;
+}
+
+static void *main_gate_write8(uint32_t address, void *vcontext, uint8_t value)
+{
+	m68k_context *m68k = vcontext;
+	genesis_context *gen = m68k->system;
+	segacd_context *cd = gen->expansion;
+	uint32_t reg = (address & 0x1FF) >> 1;
+	uint16_t value16;
+	if (address & 1) {
+		value16 = cd->gate_array[reg] & 0xFF00 | value;
+	} else {
+		value16 = cd->gate_array[reg] & 0xFF | (value << 8);
+	}
+	return main_gate_write16(address, vcontext, value16);
+}
+
+segacd_context *alloc_configure_segacd(system_media *media, uint32_t opts, uint8_t force_region, rom_info *info)
+{
+	static memmap_chunk sub_cpu_map[] = {
+		{0x000000, 0x00FEFF, 0x0000, .flags=MMAP_READ | MMAP_CODE, .write_16 = prog_ram_wp_write16, .write_8 = prog_ram_wp_write8},
+		{0x00FF00, 0x07FFFF, 0x0000, .flags=MMAP_READ | MMAP_WRITE | MMAP_CODE},
+		{0x080000, 0x0BFFFF, 0x0000, .flags=MMAP_READ | MMAP_WRITE | MMAP_CODE | MMAP_PTR_IDX | MMAP_FUNC_NULL, .ptr_index = 0,
+			.read_16 = work_ram_2M_read16, .write_16 = work_ram_2M_write16, .read_8 = work_ram_2M_read8, .write_8 = work_ram_2M_write8},
+		{0x0C0000, 0x0DFFFF, 0x0000, .flags=MMAP_READ | MMAP_WRITE | MMAP_CODE | MMAP_PTR_IDX | MMAP_FUNC_NULL, .ptr_index = 1,
+			.read_16 = work_ram_1M_read16, .write_16 = work_ram_1M_write16, .read_8 = work_ram_1M_read8, .write_8 = work_ram_1M_write8},
+		{0xFE0000, 0xFEFFFF, 0x3FFF, .flags=MMAP_READ | MMAP_WRITE | MMAP_ONLY_ODD},
+		{0xFF0000, 0xFF7FFF, 0x0000, .read_16 = pcm_read16, .write_16 = pcm_write16, .read_8 = pcm_read8, .write_8 = pcm_write8},
+		{0xFF8000, 0xFF81FF, 0x0000, .read_16 = sub_gate_read16, .write_16 = sub_gate_write16, .read_8 = sub_gate_read8, .write_8 = sub_gate_write8}
+	};
+	segacd_context *cd = calloc(sizeof(segacd_context), 1);
+	FILE *f = fopen("cdbios.bin", "rb");
+	if (!f) {
+		fatal_error("Failed to open CD firmware for reading");
+	}
+	long firmware_size = file_size(f);
+	uint32_t adjusted_size = nearest_pow2(firmware_size);
+	cd->rom = malloc(adjusted_size);
+	if (firmware_size != fread(cd->rom, 1, firmware_size, f)) {
+		fatal_error("Failed to read CD firmware");
+	}
+	cd->rom_mut = malloc(adjusted_size);
+	memcpy(cd->rom_mut, cd->rom, adjusted_size);
+	byteswap_rom(firmware_size, cd->rom);
+	cd->prog_ram = malloc(512*1024);
+	cd->work_ram = malloc(256*1024);
+	cd->pcm_ram = malloc(64*1024);
+	//TODO: Load state from file
+	cd->bram = malloc(8*1024);
+	
+	sub_cpu_map[0].buffer = sub_cpu_map[1].buffer = cd->prog_ram;
+	sub_cpu_map[4].buffer = cd->bram;
+	m68k_options *mopts = malloc(sizeof(m68k_options));
+	init_m68k_opts(mopts, sub_cpu_map, sizeof(sub_cpu_map) / sizeof(*sub_cpu_map), 4);
+	cd->m68k = init_68k_context(mopts, NULL);
+	cd->m68k->system = cd;
+	cd->busreq = 1;
+	cd->busack = 1;
+	
+	return cd;
+}
+
+memmap_chunk *segacd_main_cpu_map(segacd_context *cd, uint32_t *num_chunks)
+{
+	static memmap_chunk main_cpu_map[] = {
+		{0x000000, 0x01FFFF, 0x00000, .flags=MMAP_READ},
+		{0x020000, 0x03FFFF, 0x1FFFF, .flags=MMAP_READ|MMAP_WRITE|MMAP_PTR_IDX|MMAP_FUNC_NULL, .ptr_index = 0},//TODO: support running main CPU code from here
+		{0x040000, 0x05FFFF, 0x1FFFF, .flags=MMAP_READ}, //first ROM alias
+		//TODO: additional ROM/prog RAM aliases
+		{0x200000, 0x01FFFF, 0x1FFFF, .flags=MMAP_READ|MMAP_WRITE|MMAP_PTR_IDX|MMAP_FUNC_NULL, .ptr_index = 1},
+		{0x220000, 0x03FFFF, 0x1FFFF, .flags=MMAP_READ|MMAP_WRITE|MMAP_PTR_IDX|MMAP_FUNC_NULL, .ptr_index = 2},
+	};
+	//TODO: support cart boot maps
+	//TODO: support BRAM cart
+	main_cpu_map[0].buffer = cd->rom_mut;
+	main_cpu_map[2].buffer = cd->rom;
+	main_cpu_map[1].buffer = cd->prog_ram;
+	main_cpu_map[3].buffer = cd->work_ram;
+	main_cpu_map[3].buffer = cd->work_ram + 0x10000;
+	*num_chunks = sizeof(main_cpu_map) / sizeof(*main_cpu_map);
+	return main_cpu_map;
+}
--- a/segacd.h	Sat Oct 21 11:51:24 2017 -0700
+++ b/segacd.h	Tue Dec 12 09:44:33 2017 -0800
@@ -0,0 +1,24 @@
+#ifndef SEGACD_H_
+#define SEGACD_H_
+#include <stdint.h>
+#include "system.h"
+#include "m68k_core.h"
+
+typedef struct {
+	m68k_context *m68k;
+	system_media *media;
+	uint16_t     gate_array[0x100];
+	uint8_t      busreq;
+	uint8_t      busack;
+	uint8_t      reset;
+	uint16_t     *rom;     //unaltered ROM, needed for mirrored locations
+	uint16_t     *rom_mut; //ROM with low 16-bit of HINT vector modified by register write
+	uint16_t     *prog_ram;
+	uint16_t     *work_ram;
+	uint8_t      *pcm_ram;
+	uint8_t      *bram;
+} segacd_context;
+
+segacd_context *alloc_configure_segacd(system_media *media, uint32_t opts, uint8_t force_region, rom_info *info);
+
+#endif //SEGACD_H_