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Adds port input.

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This commit is contained in:
Thomas Harte 2021-07-18 20:25:04 -04:00
parent c425dec4d5
commit a030d9935e
3 changed files with 15 additions and 2 deletions
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8
Components/6526/6526.hpp
View File

@ -22,7 +22,12 @@ enum Port {
};
struct PortHandler {
/// Sets the current output value of @c port and provides @c direction_mask, indicating which pins are marked as output.
/// Requests the current input value of @c port from the port handler.
uint8_t get_port_input([[maybe_unused]] Port port) {
return 0xff;
}
/// Sets the current output value of @c port; any bits marked as input will be supplied as 1s.
void set_port_output([[maybe_unused]] Port port, [[maybe_unused]] uint8_t value) {}
};
@ -53,6 +58,7 @@ template <typename PortHandlerT, Personality personality> class MOS6526:
PortHandlerT &port_handler_;
template <int port> void set_port_output();
template <int port> uint8_t get_port_input();
};
}

8
Components/6526/Implementation/6526Implementation.hpp
View File

@ -21,6 +21,12 @@ template <int port> void MOS6526<BusHandlerT, personality>::set_port_output() {
port_handler_.set_port_output(Port(port), output);
}
template <typename BusHandlerT, Personality personality>
template <int port> uint8_t MOS6526<BusHandlerT, personality>::get_port_input() {
const uint8_t input = port_handler_.get_port_input(Port(port));
return (input & ~registers_.data_direction[port]) | (registers_.output[port] & registers_.data_direction[port]);
}
template <typename BusHandlerT, Personality personality>
void MOS6526<BusHandlerT, personality>::write(int address, uint8_t value) {
address &= 0xf;
@ -56,6 +62,8 @@ template <typename BusHandlerT, Personality personality>
uint8_t MOS6526<BusHandlerT, personality>::read(int address) {
address &= 0xf;
switch(address) {
case 0: return get_port_input<0>();
case 1: return get_port_input<1>();
case 2: case 3:
return registers_.data_direction[address - 2];

1
Components/6526/Implementation/6526Storage.hpp
View File

@ -16,7 +16,6 @@ struct MOS6526Storage {
struct Registers {
uint8_t output[2] = {0, 0};
uint8_t input[2] = {0, 0};
uint8_t data_direction[2] = {0, 0};
} registers_;