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====== Int 21H, AH=48H ======

===== Version =====

2 and higher

===== Brief =====

ALLOCATE MEMORYY

===== Family API =====

[[en:docs:fapi:dosallochuge|DosAllocHuge]], [[en:docs:fapi:dosallocseg|DosAllocSeg]]

===== Input =====

  AH = 48h
  BX = number of paragraphs to allocate

===== Return =====

  CF clear if successful
    AX = segment of allocated block
  CF set on error
    AX = error code (07h,08h) (see #01680 at AH=59h/BX=0000h)
    BX = size of largest available block

===== Macro =====

<code asm>
INCLUDE DOS.INC

ALLOCATE_MEMORY bytes
</code>


===== Notes =====

DOS 2.1-6.0 coalesces free blocks while scanning for a block to allocate

.COM programs are initially allocated the largest available memory block, and should free some memory with AH=49h before attempting any allocations

under the FlashTek X-32 DOS extender, EBX contains a protected-mode near pointer to the allocated block on a successful return
          
===== See also =====

 **[[en:docs:dos:api:int21|INT 21H]]:** [[en:docs:dos:api:int21:49|49H]], [[en:docs:dos:api:int21:4a|4AH]], [[en:docs:dos:api:int21:58|58H]]

===== Note =====

Text based on [[http://www.cs.cmu.edu/~ralf/files.html|Ralf Brown Interrupt List Release 61]]

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