Set Segment Limit

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

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

Returns

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

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.

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.)