IOP.SPTR
This trap sets the pointer position.
| Call Parameters | Return Parameters | ||
|---|---|---|---|
| D0.B | $7B | D0.L | Error return |
| D1.L | x,y coordinates | D1.L | x,y coordinates |
| D2.W | Origin key | D2.L | Preserved |
| D3.W | Timeout | D3.L | Preserved |
| A0.L | Channel ID | A0.L | Preserved |
Errors
| ERR_NO | Channel not open |
| ER_OR | Out of range |
Notes
- All registers not mentioned above are preserved.
- The origin key in D2.W has the following effect:
- -1 sets the pointer relative to the current window definition.
- 0 sets the pointer to the absolute position in D1.
- 1 sets the pointer relative to the hit area.
- The position returned in D1 is in absolute coordinates.
Example
The example here shows the pointer set to the top left of the screen. It is assumed that on entry A4 points to the working definition.
movea.l ww_chid(a4),a0 ; Set the channel ID (ww_chid = 8)
moveq #0,d1 ; Position 0,0 . .
moveq #9,d2 ; . . absolute
moveq #IOP_SPTR,d0
trap #3
tst.l d0 ; Errors? . .
bne err ----> ; . . yes!
george.gwilt