dreamcast/maple/maple.cpp
Zack Buhman 855cbba403 maple: write data to a VMU display
This draws a smiley-face bitmap to a VMU display on port 1.
2023-12-11 18:07:05 +08:00

116 lines
3.9 KiB
C++

#include <cstdint>
#include <bit>
#include "../sh7091.h"
#include "../sh7091_bits.h"
#include "../systembus.h"
#include "../systembus_bits.h"
#include "maple_bits.h"
#include "maple_host_bits.h"
#include "maple_bus_commands.h"
#include "maple.h"
void maple_init_host_command(uint32_t * buf, uint32_t * receive_address, uint8_t command_code, uint8_t data_size)
{
// this function does not care about the template instantiation of
// maple_host_command--data_fields is not manipulated here.
auto host_command = reinterpret_cast<maple_host_command<uint32_t> *>(buf);
host_command->host_instruction = host_instruction::end_flag
| host_instruction::port_select::a
| host_instruction::transfer_length((data_size / 4));
host_command->receive_data_storage_address = reinterpret_cast<uint32_t>(receive_address) & 0x1fff'ffff;
host_command->bus_data.command_code = command_code;
host_command->bus_data.destination_ap = ap::de::expansion_device | ap::port_select::a | ap::lm_bus::_0;
host_command->bus_data.source_ap = ap::port_select::a;
host_command->bus_data.data_size = data_size / 4;
}
void maple_init_device_request(uint32_t * buf, uint32_t * receive_address)
{
maple_init_host_command(buf, receive_address, device_request::command_code, (sizeof (struct device_request::data_fields)));
}
void maple_init_get_condition(uint32_t * buf, uint32_t * receive_address)
{
maple_init_host_command(buf, receive_address, get_condition::command_code, (sizeof (struct get_condition::data_fields)));
auto host_command = reinterpret_cast<maple_host_command<get_condition::data_fields> *>(buf);
auto& function_type = host_command->bus_data.data_fields.function_type;
// controller function type
function_type[0] = 0x00;
function_type[1] = 0x00;
function_type[2] = 0x00;
function_type[3] = 0x01;
}
void maple_init_block_write(uint32_t * buf, uint32_t * receive_address, uint32_t * data)
{
maple_init_host_command(buf, receive_address, block_write::command_code, (sizeof (struct block_write::data_fields<uint32_t[192 / 4]>)));
auto host_command = reinterpret_cast<maple_host_command<block_write::data_fields<uint32_t[192 / 4]>> *>(buf);
auto& fields = host_command->bus_data.data_fields;
// BW LCD function type
fields.function_type[0] = 0x00;
fields.function_type[1] = 0x00;
fields.function_type[2] = 0x00;
fields.function_type[3] = 0x04;
// lcd number 0 (1 total lcd)
fields.pt[0] = 0;
// phase 0 (from 0 to 3)
fields.phase[0] = 0;
// plane 0 (2 total levels of gradation)
fields.block_no[0] = 0x00;
fields.block_no[1] = 0x00;
for (uint32_t i = 0; i < (192 / 4); i++) {
fields.written_data[i] = data[i];
}
}
void maple_dma_start(uint32_t * command_buf)
{
sh7091.DMAC.DMAOR = DMAOR__DDT /* on-demand data transfer mode */
| DMAOR__PR__CH2_CH0_CH1_CH3 /* priority mode; CH2 > CH0 > CH1 > CH3 */
| DMAOR__DME; /* DMAC master enable */
// clear maple-DMA end status
system.ISTNRM = ISTNRM__END_OF_DMA_MAPLE_DMA;
// disable maple-DMA
maple_if.MDEN = mden::dma_enable::abort;
while (mdst::start_status::status(maple_if.MDST) != 0);
// 20nsec * 0xc350 = 1ms
constexpr uint32_t one_msec = 0xc350;
maple_if.MSYS = msys::time_out_counter(one_msec)
| msys::sending_rate::_2M;
/* top address: the first/lowest address
bottom address: the last/highest address */
maple_if.MDAPRO = mdapro::security_code
| mdapro::top_address(0x00)
| mdapro::bottom_address(0x7f);
maple_if.MDTSEL = mdtsel::trigger_select::software_initiation;
maple_if.MDSTAR = mdstar::table_address(reinterpret_cast<uint32_t>(command_buf));
maple_if.MDEN = mden::dma_enable::enable;
maple_if.MDST = mdst::start_status::start;
// wait for completion
//while (mdst::start_status::status(maple_if.MDST) != 0);
while ((system.ISTNRM & ISTNRM__END_OF_DMA_MAPLE_DMA) == 0);
system.ISTNRM = ISTNRM__END_OF_DMA_MAPLE_DMA;
}