qdosmsq:traps:trap_1:alhp

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qdosmsq:traps:trap_1:alhp [2009/01/30 11:29] (current)
norman created
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 +====== MT_ALLOC/SMS_ALHP ======
 +This trap allocates space from a user heap. 
 +
 +^Call Parameters^^Return Parameters^^
 +|D0.B|$0C|D0.L|Corrupted?|
 +|D1.L|Number of bytes required in user heap. |D1.L|Number of bytes allocated.|
 +|D2.L|Unused. |D2.L| Corrupted.|
 +|D3.L|Unused. |D3.L| Corrupted.|
 +|A0.L|Pointer to pointer to free space (relative A6). |A0.L|Address of area allocated.|
 +|A1.L|Unused. |A1.L| Corrupted.|
 +|A2.L|Unused. |A2.L| Corrupted.|
 +|A3.L|Unused. |A3.L| Corrupted.|
 +
 +===== Errors =====
 +|ERR_OM|Out of memory (in user heap).|
 +
 +===== Notes =====
 +
 +* All registers not shown above are not used on entry and are preserved
 +on exit.
 +
 +* A user heap is an area of memory, maybe in the common heap, set aside for use
 +by a single job. The job can allocate areas of this user heap for its own needs, and
 +deallocate them as required. This stops, or reduces fragmentation of the common heap which
 +is used by every task in the system. [[qdosmsq:memory:heaps|See here]] for more information on heaps.
 +
 +===== Example =====
 +[[qdosmsq:traps:trap_1:heaps|This example]] show the use of this, and other, heap
 +manipulation traps.
  
  • qdosmsq/traps/trap_1/alhp.txt
  • Last modified: 2009/01/30 11:29
  • by norman