Compatibility: DPMI 0.9+
Expects: AX    0009H
BX    selector
CL    access rights/type byte
CH    (386+) extended access rights/type byte
                                                                  
Returns: CF    NC (clear) if successful; else AX = DPMI Error Code
                                                                  
Info: This modifies the access rights and/or type of the LDT descriptor
identified by the selector in BX.

CL is in this form:
 7 6 5 4 3 2 1 0 
 p dpl 1 c x w a 
                  bit  mask
                   0: 01H 1=accessed; 0=not accessed
                   1: 02H 1=read/write (must be 0 in code segs)
                   2: 04H 1=expand down; 0=expand up
                   3: 08H 1=code seg; 0=data seg
                   4: 10H must be 1
                 5-6: 60H CPL (protection level) must=caller
                   7: 80H 1=present; 0=absent

CH is ignored on 80286.  On 386+, its bits mean:
 7 6 5 4 3 2 1 0 
 g b 0 v 0 0 0 0 
                  bit  mask
                 0-3: 0fH ignored
                   4: 10H AVL can be 0 or 1
                   5: 20H must be 0
                   6: 40H 1=default to 32-bit; 0=default to 16
                   7: 80H 1=page granularity; 0=byte granularity

Note: There is no corresponding fn to query the current settings.  Use
the LAR opcode to do so.

See Also: DPMI API
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INT 31H 0009H: Set Descriptor Access Rights