INT 21 P - Phar Lap 386/DOS-Extender v4.1+ - MAP DATA FILE ATIBM PC AT FILE OFFSET
	AX = 252Bh
	BH = 0Bh
	BL = subfunction
	    00h by linear address
		ECX = linear address at which to map data file
	    01h by logical address
		ES:ECX = logical address at which to map data file
	EDX = number of bytes to map
	DS:ESI -> mapping structure (see #01373)
	DS:EDI -> ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. filename
Return: CF clear if successful
	CF set on error
	    EAX = error code
		0002h file error
		    ECX = phase (01h opening file, 02h seeking, 03h reading)
		    EDX = error code returned by DOS
		0009h invalid address
		0081h invalid parameters or 386|VMM not present
		0086h all 386|VMM file handles already in use
SeeAlso: AX=252Bh/BH=03h,AX=252Bh/BH=09h


Format of Phar Lap mapping structure:
Offset	Size	Description	(Table 01373)
 00h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	starting file offset to be mapped
 04h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	DOS file access and sharing modes (see #01403 at INT 21/AH=3Dh)