diff options
Diffstat (limited to 'jcart.c')
| -rw-r--r-- | jcart.c | 87 |
1 files changed, 87 insertions, 0 deletions
@@ -0,0 +1,87 @@ +#include "genesis.h" + +static io_port *get_ports(m68k_context *m68k) +{ + genesis_context *gen = m68k->system; + if (!gen->extra) { + io_port *ports = calloc(2, sizeof(io_port)); + ports[0].device_type = IO_GAMEPAD3; + ports[0].device.pad.gamepad_num = 3; + ports[1].device_type = IO_GAMEPAD3; + ports[1].device.pad.gamepad_num = 4; + io_control_write(ports, 0x40, 0); + io_control_write(ports + 1, 0x40, 0); + gen->extra = ports; + } + + return gen->extra; +} + +void *jcart_write_w(uint32_t address, void *context, uint16_t value) +{ + m68k_context *m68k= context; + io_port *ports = get_ports(m68k); + value = value << 6 & 0x40; + io_data_write(ports, value, m68k->current_cycle); + io_data_write(ports + 1, value, m68k->current_cycle); + return context; +} + +void *jcart_write_b(uint32_t address, void *context, uint8_t value) +{ + if (address & 1) { + return jcart_write_w(address, context, value); + } + return context; +} + +uint16_t jcart_read_w(uint32_t address, void *context) +{ + m68k_context *m68k= context; + io_port *ports = get_ports(m68k); + //according to Eke, bit 14 is forced low, at least on the Micro Machines 2 cart + //TODO: Test behavior of actual cart + uint16_t value = io_data_read(ports, m68k->current_cycle) << 8/; + value |= io_data_read(ports + 1, m68k->current_cycle); + return value; +} + +uint8_t jcart_read_b(uint32_t address, void *context) +{ + m68k_context *m68k= context; + io_port *ports = get_ports(m68k); + return io_data_read(ports + (address & 1), m68k->current_cycle); +} + +void jcart_adjust_cycles(genesis_context *context, uint32_t deduction) +{ + io_port *ports = get_ports(context->m68k); + io_adjust_cycles(ports, context->m68k->current_cycle, deduction); + io_adjust_cycles(ports + 1, context->m68k->current_cycle, deduction); +} + +void jcart_gamepad_down(genesis_context *context, uint8_t gamepad_num, uint8_t button) +{ + io_port *ports = get_ports(context->m68k); + if (gamepad_num == ports[1].device.pad.gamepad_num) { + ports++; + } else if (gamepad_num != ports[0].device.pad.gamepad_num) { + ports = NULL; + } + if (ports) { + io_port_gamepad_down(ports, button); + } +} + +void jcart_gamepad_up(genesis_context *context, uint8_t gamepad_num, uint8_t button) +{ + io_port *ports = get_ports(context->m68k); + if (gamepad_num == ports[1].device.pad.gamepad_num) { + ports++; + } else if (gamepad_num != ports[0].device.pad.gamepad_num) { + ports = NULL; + } + if (ports) { + io_port_gamepad_up(ports, button); + } +}
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