qdosmsq:traps:trap_3:sova
Table of Contents
SD_SETMD/IOW_SOVA
This trap sets the character writing or plotting mode.
| Call Parameters | Return Parameters | ||
|---|---|---|---|
| D0.B | $2C | D0.L | Error code. |
| D1.W | Mode | D1.L | Corrupted. |
| D3.W | Timeout. | D3.L | Preserved. |
| A0.L | Channel ID. | A0.L | Preserved. |
| A1.L | A1.L | Corrupted. | |
Errors
| ERR_NC | Not complete. |
| ERR_NO | Channel not open. |
Notes
- All registers not shown above are not used on entry and are preserved on exit.
- The mode given in D1 is:
- -1 ink XORed into the background.
- 0 character background is strip colour; plotting is in ink colour.
- 1 character background is transparent so it is not overwritten; plotting is in ink colour.
Example
The example below shows how to use this trap call to make printing appear and then disappear. The mode is set to -1 then printing can be done. After a wait the printing is again done and it now disappears. It is assumed that A0 contains the channel ID.
Setmd moveq #-1,d1 ; Set XOR mode.
moveq #-1,d3 ; Timeout.
moveq #SD_SETMD,d0 ; $2C
trap #3 ; Set the mode
tst.l d0 ; OK? . .
bne error ----> ; . . no!
bsr print ; Print something at 0,0
bsr wait ; Wait for a bit.
bsr print ; The printing disappears.
qdosmsq/traps/trap_3/sova.txt · Last modified: 2009/03/02 17:20 by george.gwilt
