; any bytes left?
        JZ      __X                     ; if not, exit loop
;
__C1:   IN      AL,CRT_STAT             ; read GDC status
        TEST    AL,=FF                  ; fifo full?
        JNZ     __C1                    ; if so, wait
        MOV     DL,1[BX]                ; load port (command or parm)
        MOV     AL,0[BX]                ; load value
        OUT     DX,AL                   ; and send it
        INC     BX
        INC     BX
        DEC     AH                      ; count words down
        JMPS    __LOOP                  ; and continue loop
;
__X:    POP     DX
        POPF                            ; restore interrupt status
        RET                             ; else, exit
;
;
; Wait for GDC fifo empty out.
;
GDCFE:  IN      AL,CRT_STAT             ; read GDC status
        TEST    AL,=FE                  ; fifo empty?
        JZ      GDCFE                   ; if so, continue loop
        RET                             ; else, exit

;
;
; Read a GDC returned parameter.
;
GDCIN:  IN      AL,CRT_STAT             ; read status
        TEST    AL,=DR                  ; data ready?
        JZ      GDCIN                   ; if not, loop
        IN      AL,CRT_PARM             ; read the data
        RET                             ; and return it
;
        END