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;* GetPSP - Gets address of Program Segment Prefix. For DOS 3.0 or higher.
;*
;* Shows:   DOS Function - 62h (Get PSP Address)
;*          Instruction - call (See the MISCDEMO.ASM example program
;*                        for an example of a call dispatch table)
;*
;* Params:  None
;*
;* Return:  Short integer with PSP segment address
;*          or 0 if DOS version below 3.0
 
        EXTRN GetVer:PROC
 
GetPSP  PROC
 
        call    GetVer                  ; Get DOS version number
        cmp     ax, 300                 ; Version 3.0 or higher?
        jb      dos2                    ; No?  Return error code
        mov     ah, 62h                 ; Yes?  Query DOS for PSP
        int     21h                     ; Get PSP Address
        mov     ax, bx                  ; Put in AX
        jmp     SHORT exit              ; Exit
dos2:   sub     ax, ax                  ; For version 2, return 0
exit:   ret
 
GetPSP  ENDP
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