This routine reads from the onboard CMOS clock.
For systems without a CMOS clock, the MOS passes the calls to sideways ROM's for support.
The first byte of the parameter block is a function code representing the action required. The rest of the block's content (including its size) depends on that function.
Return clock value as string
On entry:
XY=0
On exit:
| XY+ | Length | Content | Value range | |
|---|---|---|---|---|
| 0 | 24 | Date | CR-terminated string in form | "Day,DD Mon Year.HH:MM:SS". |
Return BCD clock value
On entry:
XY=1
On exit:
| XY+ | Length | Content | Value range | |
|---|---|---|---|---|
| 0 | 1 | year | 0x00 | 0x99 |
| 1 | 1 | month | 0x01 | 0x12 |
| 0 | 1 | day | 0x01 | 0x31 |
| 0 | 1 | day of week | 0x01 Sun | 0x07 Sat |
Notes:
- year
- 0x80-0x99 represents 1980-1999. 0x00-0x79 represents 2000-2079.
- day of week
- 0x00 = not returned
Convert BCD to string
On entry:
XY=1
XY+1…7 the BCD value as returned above
On exit:
XY+1…25 CR terminated string
| XY+ | Length | Content | Value range | |
|---|---|---|---|---|
| 0 | 1 | year | 0x00 | 0x99 |