MT_SUSJB/SMS.SSJB - Suspend an Existing Job
Suspend an existing job. (ok, how do I suspend a non-existing job then? LOL)
| Call Parameters | Return Register | Return Parameter | |
|---|---|---|---|
| D0.B | $08 | D0.L | Error code. |
| D1.L | Id of the job to be suspended. -1 indicates the current job. | D1.L | Preserved. Unless the job id of -1 was used on entry, in which case the return value is the job id of the current job. |
| D2.L | Unused. | D2.L | Preserved. |
| D3.W | Timeout period in frames. -1 indicates indefinite suspension. | D3.L | Preserved. |
| A0.L | Unused. | A0.L | Base address of suspended job. |
| A1.L | Address of the flag byte (see below) or zero. | A1.L | Preserved. (or is it? See notes below.). |
Errors
| Error Code | Description |
|---|---|
| ERR_NJ | Invalid job id. |
Notes
- All registers not shown above are not used on entry and are preserved on exit.
- A1.L is documented as being preserved, but personal experience has shown that it is //not always// preserved.
- The value in D3.W is stored in the job’s header at JB_STAT.
- The value in A1.L is stored in the header at JB_HOLD. The flag byte at (A1) will be cleared when the job is released (unsupended) again.
- A frame period is 1/50th of a second in UK/Europe but 1/60th in the USA.
- If the job being suspended is already suspended, then the current suspend period is changed to the new one, and the job is re-suspended for the new period of time in full.
- This trap always exits via the job scheduler, so it is not atomic.
Example
The following shows the use of this call.
moveq #SMS.SSJB,d0 ; Or MT_SUSJB
moveq #-1,d1 ; Suspend myself
moveq #50,d3 ; Suspend for 50 frames
suba.l a1,a1 ; No flag byte required
trap #1 ; Suspend the job
...
<Carry on as normal when the suspension is over.>
...