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Hack in read-only versions of the main registers.

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This commit is contained in:
Thomas Harte 2023-12-06 23:25:34 -05:00
parent 5fde3b8d5d
commit e3119a4904
1 changed files with 55 additions and 2 deletions
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57
Machines/PCCompatible/RTC.hpp
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@ -9,6 +9,8 @@
#ifndef RTC_h
#define RTC_h
#include <ctime>
namespace PCCompatible {
class RTC {
@ -22,17 +24,68 @@ class RTC {
// NMI not yet supported.
break;
case 1:
// TODO.
write_register(value);
break;
}
}
uint8_t read() {
return 0x00;
std::time_t now = std::time(NULL);
std::tm *time_date = std::localtime(&now);
switch(selected_) {
default:
return 0xff;
case 0x00: return bcd(time_date->tm_sec); // Seconds [0-59]
case 0x01: return 0; // Seconds alarm
case 0x02: return bcd(time_date->tm_min); // Minutes [0-59]
case 0x03: return 0; // Minutes alarm
case 0x04:
// Hours [1-12 or 0-23]
if(statusB_ & 2) {
return bcd(time_date->tm_hour);
}
return bcd(1 + (time_date->tm_hour + 11)%12);
break;
case 0x05: return 0; // Hours alarm
case 0x06: return bcd(time_date->tm_wday + 1); // Day of the week [Sunday = 1]
case 0x07: return bcd(time_date->tm_mon); // Date of the Month [1-31]
case 0x08: return bcd(time_date->tm_mon + 1); // Month [1-12]
case 0x09: return bcd(time_date->tm_year % 100); // Year [0-99]
case 0x32: return bcd(19 + time_date->tm_year / 100); // Century
case 0x0a: return statusA_;
case 0x0b: return statusB_;
}
}
private:
int selected_;
uint8_t statusA_ = 0x00;
uint8_t statusB_ = 0x00;
template <typename IntT>
uint8_t bcd(IntT input) {
// If calendar is in binary format, don't convert.
if(statusB_ & 4) {
return uint8_t(input);
}
// Convert a one or two digit number to BCD.
return uint8_t(
(input % 10) +
((input / 10) * 16)
);
}
void write_register(uint8_t value) {
switch(selected_) {
default: break;
case 0x0a: statusA_ = value; break;
}
}
};
}