Format of DPMI real mode call structure: Offset Size Description ) 00h DWORD EDI 04h DWORD ESI 08h DWORD EBP 0Ch DWORD reserved (00h) 10h DWORD EBX 14h DWORD EDX 18h DWORD ECX 1Ch DWORD EAX 20h WORD flags 22h WORD ES 24h WORD DS 26h WORD FS 28h WORD GS 2Ah WORD IP 2Ch WORD CS 2Eh WORD SP 30h WORD SS