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====== Int 21H, AH=58H, AL=01H ======

===== Version =====

2.11 and higher

===== Brief =====

SET MEMORY ALLOCATION STRATEGY

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


===== Input =====

	AH = 58h
	AL = 01h 
	BL = new allocation strategy (see #01679)
	BH = 00h (DOS 5+)

===== Return =====

    CF clear if successful
	CF set on error
	    AX = error code (01h) (see #01680)

===== Notes =====

the Get subfunction returns the last value set

setting an allocation strategy involving high memory does not automatically link in the UMB memory chain; this must be done explicitly with AX=5803h in order to actually allocate high memory

a program which changes the allocation strategy should restore it before terminating

Toshiba MS-DOS v2.11 supports subfunctions 00h and 01h, as does the TI Professional MS-DOS v2.13

DR DOS 3.41 reportedly reverses subfunctions 00h and 01h
    
Values for DOS memory allocation strategy:

| 00h | low memory first fit |
| 01h | low memory best fit |
| 02h | low memory last fit |
| ---DOS 5+ --- ||
| 40h | high memory first fit |
| 41h | high memory best fit |
| 42h | high memory last fit |
| 80h | first fit, try high then low memory |
| 81h | best fit, try high then low memory |
| 82h | last fit, try high then low memory |
   
===== See also =====

AH=[[en:docs:dos:api:int21:48|48h]],AH=[[en:docs:dos:api:int21:49|49h]],AH=[[en:docs:dos:api:int21:4a|4Ah]],INT 2F/AX=4310h"XMS",INT 67/AH=3Fh

===== Note =====

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

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