diff options
Diffstat (limited to 'genesis.c')
| -rw-r--r-- | genesis.c | 113 |
1 files changed, 100 insertions, 13 deletions
@@ -752,9 +752,8 @@ static m68k_context * io_write(uint32_t location, m68k_context * context, uint8_ } } } else { - location &= 0x1FFF; - if (location < 0x100) { - switch(location/2) + if (location < 0x10100) { + switch(location >> 1 & 0xFF) { case 0x1: io_data_write(gen->io.ports, value, context->current_cycle); @@ -799,7 +798,8 @@ static m68k_context * io_write(uint32_t location, m68k_context * context, uint8_ break; } } else { - if (location == 0x1100) { + uint32_t masked = location & 0xFFF00; + if (masked == 0x11100) { if (value & 1) { dputs("bus requesting Z80"); if (z80_enabled) { @@ -824,7 +824,7 @@ static m68k_context * io_write(uint32_t location, m68k_context * context, uint8_ gen->z80->busack = 0; } } - } else if (location == 0x1200) { + } else if (masked == 0x11200) { sync_z80(gen->z80, context->current_cycle); if (value & 1) { if (z80_enabled) { @@ -840,6 +840,8 @@ static m68k_context * io_write(uint32_t location, m68k_context * context, uint8_ } ym_reset(gen->ym); } + } else if (masked != 0x11300 && masked != 0x11000) { + fatal_error("Machine freeze due to unmapped write to address %X\n", location | 0xA00000); } } } @@ -876,16 +878,18 @@ static uint8_t io_read(uint32_t location, m68k_context * context) } else if (location < 0x6000) { sync_sound(gen, context->current_cycle); value = ym_read_status(gen->ym, context->current_cycle, location); + } else if (location < 0x7F00) { + value = 0xFF; } else { + fatal_error("Machine freeze due to read of Z80 VDP memory window by 68K: %X\n", location | 0xA00000); value = 0xFF; } } else { value = 0xFF; } } else { - location &= 0x1FFF; - if (location < 0x100) { - switch(location/2) + if (location < 0x10100) { + switch(location >> 1 & 0xFF) { case 0x0: //version bits should be 0 for now since we're not emulating TMSS @@ -937,18 +941,24 @@ static uint8_t io_read(uint32_t location, m68k_context * context) value = gen->io.ports[2].serial_ctrl; break; default: - value = 0xFF; + value = get_open_bus_value(&gen->header) >> 8; } } else { - if (location == 0x1100) { + uint32_t masked = location & 0xFFF00; + if (masked == 0x11100) { value = z80_enabled ? !z80_get_busack(gen->z80, context->current_cycle) : !gen->z80->busack; value |= (get_open_bus_value(&gen->header) >> 8) & 0xFE; dprintf("Byte read of BUSREQ returned %d @ %d (reset: %d)\n", value, context->current_cycle, gen->z80->reset); - } else if (location == 0x1200) { + } else if (masked == 0x11200) { value = !gen->z80->reset; + } else if (masked == 0x11300 || masked == 0x11000) { + //A11300 is apparently completely unused + //A11000 is the memory control register which I am assuming is write only + value = get_open_bus_value(&gen->header) >> 8; } else { + location |= 0xA00000; + fatal_error("Machine freeze due to read of unmapped IO location %X\n", location); value = 0xFF; - printf("Byte read of unknown IO location: %X\n", location); } } } @@ -1060,6 +1070,80 @@ static void *z80_write_bank_reg(uint32_t location, void * vcontext, uint8_t valu return context; } +static uint16_t unused_read(uint32_t location, void *vcontext) +{ + m68k_context *context = vcontext; + genesis_context *gen = context->system; + if ((location >= 0xA13000 && location < 0xA13100) || (location >= 0xA12000 && location < 0xA12100)) { + //Only called if the cart/exp doesn't have a more specific handler for this region + return get_open_bus_value(&gen->header); + } else if (location == 0xA14000 || location == 0xA14002) { + if (gen->version_reg & 0xF) { + return gen->tmss_lock[location >> 1 & 1]; + } else { + fatal_error("Machine freeze due to read from TMSS lock when TMSS is not present %X\n", location); + return 0xFFFF; + } + } else if (location == 0xA14100) { + if (gen->version_reg & 0xF) { + return get_open_bus_value(&gen->header); + } else { + fatal_error("Machine freeze due to read from TMSS control when TMSS is not present %X\n", location); + return 0xFFFF; + } + } else { + fatal_error("Machine freeze due to unmapped read from %X\n", location); + return 0xFFFF; + } +} + +static uint8_t unused_read_b(uint32_t location, void *vcontext) +{ + uint16_t v = unused_read(location & 0xFFFFFE, vcontext); + if (location & 1) { + return v; + } else { + return v >> 8; + } +} + +static void *unused_write(uint32_t location, void *vcontext, uint16_t value) +{ + m68k_context *context = vcontext; + genesis_context *gen = context->system; + uint8_t has_tmss = gen->version_reg & 0xF; + if (has_tmss && (location == 0xA14000 || location == 0xA14002)) { + gen->tmss_lock[location >> 1 & 1] = value; + } else if (has_tmss && location == 0xA14100) { + //TODO: implement TMSS control register + } else { + fatal_error("Machine freeze due to unmapped write to %X\n", location); + } + return vcontext; +} + +static void *unused_write_b(uint32_t location, void *vcontext, uint8_t value) +{ + m68k_context *context = vcontext; + genesis_context *gen = context->system; + uint8_t has_tmss = gen->version_reg & 0xF; + if (has_tmss && location >= 0xA14000 && location <= 0xA14003) { + uint32_t offset = location >> 1 & 1; + if (location & 1) { + gen->tmss_lock[offset] &= 0xFF00; + gen->tmss_lock[offset] |= value; + } else { + gen->tmss_lock[offset] &= 0xFF; + gen->tmss_lock[offset] |= value << 8; + } + } else if (has_tmss && (location == 0xA14100 || location == 0xA14101)) { + //TODO: implement TMSS control register + } else { + fatal_error("Machine freeze due to unmapped byte write to %X\n", location); + } + return vcontext; +} + static void set_speed_percent(system_header * system, uint32_t percent) { genesis_context *context = (genesis_context *)system; @@ -1548,7 +1632,10 @@ genesis_context *alloc_config_genesis(void *rom, uint32_t rom_size, void *lock_o (read_8_fun)vdp_port_read_b, (write_8_fun)vdp_port_write_b}, {0xA00000, 0xA12000, 0x1FFFF, 0, 0, 0, NULL, (read_16_fun)io_read_w, (write_16_fun)io_write_w, - (read_8_fun)io_read, (write_8_fun)io_write} + (read_8_fun)io_read, (write_8_fun)io_write}, + {0x000000, 0xFFFFFF, 0xFFFFFF, 0, 0, 0, NULL, + (read_16_fun)unused_read, (write_16_fun)unused_write, + (read_8_fun)unused_read_b, (write_8_fun)unused_write_b} }; static tern_node *rom_db; if (!rom_db) { |