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====== Int 31H, AH=00H, AL=08H ======

===== Version =====

0.9

===== Brief =====

Set Segment Limit [0.9]

===== Input =====

  AX = 0008H
  BX = selector
  CX:DX = 32-bit segment limit

===== Return =====

  if function successful
  Carry flag = clear
  
  if function unsuccessful
  Carry flag = set
  AX = error code
  8021H	invalid value (CX <> 0 on a 16-bit DPMI host; or the limit is greater than 1 MB, but the low twelve bits are not set)
  8022H	invalid selector
  8025H	invalid linear address (changing the limit would cause the descriptor to reference a linear address range outside that allowed for DPMI clients.)

===== Notes =====

Sets the limit field in the LDT descriptor for the specified segment.

The value supplied to the function in CX:DX is the byte length of the segment-1 (i.e., the value returned by the LSL instruction).

Segment limits greater than or equal to 1 MB must be page-aligned. That is, limits greater than 1 MB must have the low 12 bits set.

This function has an implicit effect on the "G" (granularity) bit in an 80386 descriptor's extended access rights/type byte; i.e., it is the host's responsibility to set the "G" bit correctly.

Client programs must use the LSL instruction to query the limit for a descriptor. Note that on 80386 machines, the client must use the 32-bit form of LSL if the segment size is greater than 64 KB.

A DPMI 1.0 host will reload any segment registers which contain the 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.

    
===== See also =====

   

===== Note =====

Text based on [[http://www.delorie.com/djgpp/doc/dpmi/]]

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