a) The value supplied to the function in CX:DX is the byte length of the segment-1 (ie, the value returned by the LSL instruction).
b) 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.
c) This function has an implicit effect on the "G" (granularity) bit in an 80386+ descriptor's extended access rights/type byte; ie, it is the host's responsibility to set the "G" bit correctly.
d) 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.
e) DOS/32 Advanced DPMI and DPMI 1.0 hosts will reload any segment registers which contain the selector specified in register BX.