INT 1A - PCMCIA Socket Services - READ ONE
        AH = 91h
        AL = adapter number
        BL = socket number (01h to maximum supported by adapter)
        BH = attributes (see below)
        DX:SI = card address
Return: CF clear if successful
            AH destroyed
            CL/CX = value read
        CF set on error
            AH = error code (01h,07h,09h,0Bh,14h) (see AH=80h"PCMCIA")
            CX may be destroyed
Note:   this function is only valid for I/O-mapped sockets
SeeAlso: AH=92h,AH=93h,INT 21/AX=440Dh"IOCTL"

Bitfields for attributes:
 bit 0  attribute memory instead of common memory
 bit 1  word rather than byte
 bit 2  even bytes only

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