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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,6 +1,7 @@ | ||
| pub mod bus; | ||
| pub mod iwm; | ||
| pub mod keyboard; | ||
| pub mod rtc; | ||
| pub mod scc; | ||
| pub mod via; | ||
| pub mod video; |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,164 @@ | ||
| use chrono::{Local, NaiveDate}; | ||
| use log::*; | ||
|
|
||
| /// Macintosh Real-Time Clock | ||
| pub struct Rtc { | ||
| io_enable: bool, | ||
| io_clk: bool, | ||
|
|
||
| write_cmd: Option<u8>, | ||
| byte_in: u8, | ||
| byte_in_bit: usize, | ||
| data_out: u8, | ||
| sending: bool, | ||
|
|
||
| data: RtcData, | ||
| } | ||
|
|
||
| #[derive(Default)] | ||
| pub struct RtcData { | ||
| writeprotect: bool, | ||
| seconds: u32, | ||
| pram: [u8; 0x14], | ||
| } | ||
|
|
||
| impl Default for Rtc { | ||
| fn default() -> Self { | ||
| // Initialize clock from host system | ||
| let seconds = Local::now() | ||
| .naive_local() | ||
| .signed_duration_since( | ||
| NaiveDate::from_ymd_opt(1904, 1, 1) | ||
| .unwrap() | ||
| .and_hms_opt(0, 0, 0) | ||
| .unwrap(), | ||
| ) | ||
| .num_seconds() as u32; | ||
|
|
||
| Self { | ||
| io_enable: false, | ||
| io_clk: false, | ||
| write_cmd: None, | ||
| byte_in: 0, | ||
| byte_in_bit: 0, | ||
| data_out: 0, | ||
| sending: false, | ||
| data: RtcData { | ||
| writeprotect: true, | ||
| seconds, | ||
| pram: [0; 0x14], | ||
| }, | ||
| } | ||
| } | ||
| } | ||
|
|
||
| impl Rtc { | ||
| /// Pokes the RTC that one second has passed | ||
| /// In the emulator, one second interrupt is driven by the VIA for ease. | ||
| pub fn second(&mut self) { | ||
| self.data.seconds = self.data.seconds.wrapping_add(1); | ||
| } | ||
|
|
||
| /// Updates RTC I/O lines from the VIA. | ||
| pub fn io(&mut self, enable: bool, clk: bool, data: bool) -> bool { | ||
| let mut res = true; | ||
|
|
||
| if enable { | ||
| // Disabled | ||
| self.io_enable = true; | ||
| return true; | ||
| } | ||
| if !enable && self.io_enable { | ||
| // Reset | ||
| self.io_enable = false; | ||
| self.data_out = 0; | ||
| self.write_cmd = None; | ||
| self.byte_in = 0; | ||
| self.byte_in_bit = 0; | ||
| self.sending = false; | ||
| } | ||
|
|
||
| if !self.sending && clk && !self.io_clk { | ||
| // Receiving command | ||
| self.byte_in <<= 1; | ||
| if data { | ||
| self.byte_in |= 1; | ||
| } | ||
| self.byte_in_bit += 1; | ||
| if self.byte_in_bit >= 8 { | ||
| if let Some(cmd) = self.write_cmd { | ||
| // Second byte of write | ||
| self.cmd_write(cmd, self.byte_in); | ||
| self.write_cmd = None; | ||
| } else if self.byte_in & 0x80 == 0 { | ||
| // Write - read another byte | ||
| self.write_cmd = Some(self.byte_in); | ||
| } else { | ||
| self.data_out = self.cmd_read(self.byte_in); | ||
| self.sending = true; | ||
| } | ||
| self.byte_in = 0; | ||
| self.byte_in_bit = 0; | ||
| } | ||
| } else if self.sending && clk && !self.io_clk { | ||
| // Sending response | ||
| res = self.data_out & 0x80 != 0; | ||
| self.data_out = self.data_out.wrapping_shl(1); | ||
| } | ||
|
|
||
| self.io_clk = clk; | ||
| res | ||
| } | ||
|
|
||
| /// Process a command from the CPU that writes to the RTC | ||
| fn cmd_write(&mut self, cmd: u8, val: u8) { | ||
| let scmd = (cmd >> 2) & 0b11111; | ||
| match scmd { | ||
| 0x00 | 0x04 => { | ||
| self.data.seconds = (self.data.seconds & 0xFFFFFF00) | (val as u32); | ||
| } | ||
| 0x01 | 0x05 => { | ||
| self.data.seconds = (self.data.seconds & 0xFFFF00FF) | ((val as u32) << 8); | ||
| } | ||
| 0x02 | 0x06 => { | ||
| self.data.seconds = (self.data.seconds & 0xFF00FFFF) | ((val as u32) << 16); | ||
| } | ||
| 0x03 | 0x07 => { | ||
| self.data.seconds = (self.data.seconds & 0x00FFFFFF) | ((val as u32) << 24); | ||
| } | ||
| 0x0C => { | ||
| // Test register | ||
| } | ||
| 0x0D => self.data.writeprotect = val & 0x80 != 0, | ||
| 0x08..=0x0B => { | ||
| self.data.pram[usize::from(scmd - 0x08)] = val; | ||
| } | ||
| 0x10..=0x1F => { | ||
| self.data.pram[usize::from(scmd - 0x10 + 4)] = val; | ||
| } | ||
| _ => { | ||
| warn!( | ||
| "Unknown RTC write command: {:02X} {:08b}, data: {:02X}", | ||
| cmd, cmd, val | ||
| ); | ||
| } | ||
| } | ||
| } | ||
|
|
||
| /// Process a command from the CPU that reads from the RTC | ||
| fn cmd_read(&self, cmd: u8) -> u8 { | ||
| let scmd = (cmd >> 2) & 0b11111; | ||
| match scmd { | ||
| 0x00 | 0x04 => self.data.seconds as u8, | ||
| 0x01 | 0x05 => (self.data.seconds >> 8) as u8, | ||
| 0x02 | 0x06 => (self.data.seconds >> 16) as u8, | ||
| 0x03 | 0x07 => (self.data.seconds >> 24) as u8, | ||
| 0x08..=0x0B => self.data.pram[usize::from(scmd - 0x08)], | ||
| 0x10..=0x1F => self.data.pram[usize::from(scmd - 0x10 + 4)], | ||
| _ => { | ||
| warn!("Unknown RTC read command: {:02X} {:08b}", cmd, cmd); | ||
| 0 | ||
| } | ||
| } | ||
| } | ||
| } |
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