Int 31H Function 000CH
Copies the contents of an 8-byte buffer into the LDT
descriptor for the specified selector.
AX = 000CH
BX = selector
ES:(E)DI = selector:offset of 8-byte buffer containing
if function successful
Carry flag = clear
if function unsuccessful
Carry flag = set
AX = error code
|8021H||invalid value (access rights/type byte
|8025H||invalid linear address (descriptor references a
linear address range outside that allowed for DPMI clients)|
- 32-bit programs must use ES:EDI to point to the buffer. 16-bit
programs should use ES:DI.
- The descriptor's access rights/type byte (byte 5) follows the same
format and restrictions as the access rights/type parameter (in CL)
for the Set Descriptor Access Rights function (Int 31H Function 0009H). On 80386 (or later)
machines, the descriptor's extended access rights/type byte (byte 6)
follows the same format and restrictions as the extended access
rights/type parameter (in CH) for the same function, except the
low-order 4 bits (marked "reserved") are used to set the upper 4 bits
of the descriptor's limit.
- If the descriptor's present bit is not set, then the only error
checking is that the client's CPL must be equal to the descriptor's
DPL field and the "must be 1" bit in the descriptor's byte 5 must be
- A DPMI 1.0 host will reload any segment register which contains a
selector specified in register BX. It is suggested that DPMI 0.9
hosts also implement this.
- Refer to the rules for descriptor usage in Appendix D.