6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2026-04-24 05:18:36 +00:00
Code Issues Projects Releases Wiki Activity

Attempts to implement transmission interrupts and ClockingHint::Source.

Browse Source
This commit is contained in:
Thomas Harte
2019-10-12 23:46:57 -04:00
parent 4e5b440145
commit a7ed357569
2 changed files with 33 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Components/6850/6850.cpp
+25 -7
View File
@@ -18,12 +18,14 @@ ACIA::ACIA() {}
uint8_t ACIA::read(int address) {
if(address&1) {
LOG("Read from receive register");
interrupt_request_ = false;
} else {
LOG("Read status");
return
((next_transmission_ == NoTransmission) ? 0x02 : 0x00) |
(data_carrier_detect.read() ? 0x04 : 0x00) |
(clear_to_send.read() ? 0x08 : 0x00)
(clear_to_send.read() ? 0x08 : 0x00) |
(interrupt_request_ ? 0x80 : 0x00)
;
// b0: receive data full.
@@ -42,6 +44,8 @@ void ACIA::write(int address, uint8_t value) {
if(address&1) {
next_transmission_ = value;
consider_transmission();
update_clocking_observer();
interrupt_request_ = false;
} else {
if((value&3) == 3) {
transmit.reset_writing();
@@ -82,16 +86,22 @@ void ACIA::write(int address, uint8_t value) {
void ACIA::run_for(HalfCycles length) {
// Transmission.
int transmit_advance = length.as_int();
if(next_transmission_ != NoTransmission) {
const auto write_data_time_remaining = transmit.write_data_time_remaining();
if(transmit_advance > write_data_time_remaining) {
const int transmit_advance = length.as_int();
const auto write_data_time_remaining = transmit.write_data_time_remaining();
if(transmit_advance > write_data_time_remaining) {
if(next_transmission_ != NoTransmission) {
transmit.flush_writing();
transmit_advance -= write_data_time_remaining;
consider_transmission();
transmit.advance_writer(transmit_advance - write_data_time_remaining);
} else {
transmit.advance_writer(transmit_advance);
update_clocking_observer();
interrupt_request_ |= transmit_interrupt_enabled_;
}
} else {
transmit.advance_writer(transmit_advance);
}
transmit.advance_writer(transmit_advance);
// Reception.
}
@@ -129,3 +139,11 @@ void ACIA::consider_transmission() {
next_transmission_ = NoTransmission;
}
}
ClockingHint::Preference ACIA::preferred_clocking() {
return (transmit.write_data_time_remaining() > 0) ? ClockingHint::Preference::JustInTime : ClockingHint::Preference::None;
}
bool ACIA::get_interrupt_line() {
return interrupt_request_;
}