;**************************************************************
;***    XMS11.ASM                                           ***
;***                                                        ***
;***    function        XMS_Xms.freeUM(                     ***
;***                        address:        Pointer)        ***
;***                        : Boolean;                      ***
;***                                                        ***
;***    Frees a previously allocated Upper Memory Block     ***
;***                                                        ***
;**************************************************************

        .model  large,pascal 

        include xmsdefs.asm 

        extrn   errno:WORD  
        extrn   xmsHandler:DWord

;
;   Define entry point
;
        public  XMS_Xms@freeUM

        .code

XMS_Xms@freeUM  proc    addressHi:Word, addressLo:Word, self:DWord

        mov     ax,addressLo        ; Get offset
        or      ax,ax               ; See if it's zero (better be)
        jnz     offsetError         ; It's no good

        mov     dx,addressHi        ; Block segment address
        mov     ah,XMSFreeUM        ; Function code
        call    xmsHandler          ; call the guy

        or      ax,ax               ; AX=0 means error
        jz      errorReturn

        mov     ax,XMSErrOK         ; No error
        ret

offsetError:
        mov     bl,XMSErrUMBInv     ; bogus UMB

errorReturn:
        mov     al,bl               ; Move error code to AL
        xor     ah,ah               ; Zero extend to 16 bits
        mov     errno,ax            ; Copy to errno

        ret

XMS_Xms@freeUM  endp                ; end of procedure

        end