INT 31 P - DPMIsee DOS Protected-Mode Interface 0.9+ - ALLOCATE MEMORY BLOCK
	AX = 0501h
	BX:CX = size in bytes
Return: CF clear if successful
	    BX:CX = linear address of block
	    SI:DI = memory block handle for resizing and freeing block
	CF set on error
	    AX = error code (DPMIsee DOS Protected-Mode Interface 1.0+) (8012h-8014h,8016h,8021h)(see #03143)
Notes:	no selectors are allocated
	the memory block is allocated unlocked (can be locked with AX=0600h)
	allocations are often page granular (see AX=0604h)
	under MS Windows 3.10 Enhanced mode with paging enabled, it is possible
	  for this function to fail even if AX=0500h indicates that enough
	  memory is available
SeeAlso: AX=0000h,AX=0100h,AX=0500h,AX=0502h,AX=0503h,AX=0504h,AX=0D00h
SeeAlso: INT 2F/AX=FB42h/BX=0002h