qdosmsq:vectors:rchp

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qdosmsq:vectors:rchp [2008/06/27 19:26]
norman created
qdosmsq:vectors:rchp [2008/06/27 19:29] (current)
norman Fixed bugs in three lines of code!
Line 1: Line 1:
 +====== MM_RECHP/MEM_RCHP - Vector $C2 ======
 +This vector deallocates memory on the common heap. It should only be called in supervisor mode. The vector is atomic. The memory being deallocated should have been allocated using [[qdosmsq:vectors:achp|MM_ALCHP/MEM_ACHP]].
 +
 +^Call Parameters^^Return Parameters^^
 +|D1.L|Unused. |D1.L|Corrupted.|
 +|D2.L|Unused. |D2.L|Corrupted.|
 +|D3.L|Unused. |D3.L|Corrupted.|
 +|A0.L|Address of area to deallocate. |A0.L|Corrupted.|
 +|A1.L|Unused. |A1.L|Corrupted.|
 +|A2.L|Unused. |A2.L|Corrupted.|
 +|A3.L|Unused. |A3.L|Corrupted.|
 +|A6.L|System variables address |A6.L|Preserved.|
 +
 +===== Errors =====
 +No errors are returned by this vector call.
 +
 +===== Notes =====
 +  * All registers not shown above are not used on entry and are preserved on exit.
 +  * **Must** be called in supervisor mode only.
 +  * Mainly used in device driver 'close' routines to deallocate space used for channel definition blocks and so on.
 +  * This vector call is //atomic//.
 +
 +
 +===== Example =====
 +The example below shows the use of this vector to deallocate a previously allocated chunk of memory. For the sake of the example, the start address of the area is assumed to be on the top of the stack.
 +
 +<code>
 +Kill_hp move.w  MM_RECHP,A2     ; MM_RECHP vector address.
 +        movea.l (a7)+,a0        ; Unstack the start of the allocated area.
 +                                ; Assume A6 is correct already.
 +        jsr      (a2)           ; Make the call.
 +        ...                     ; Carry on here.
 +</code>
  
  • qdosmsq/vectors/rchp.txt
  • Last modified: 2008/06/27 19:29
  • by norman