;-------------------------------------
;-- testVID.asm
;--  Sends chars to display. Should test DSR on first output,
;--  but doesn't since this supposedly runs before any other
;--  code at boot time.
;-------------------------------------

    ;;;;;;============= clear 80X24 screen
    ld r0, ZERO
    ld r4, CR
    ld r3, NUM24          ;-- row = 24
disp1:
    ld r2, NUM80          ;-- col = 80
poll1:
    ld r0, ZERO
    ldi r1, DSR           ;-- Check DSR to see if ready
    BRzp poll1            ;--   No: poll again
    sti r0, DDR           ;-- send char to display DDR
    add r2, r2, -1        ;-- col--
    BRp poll1
poll2:
    ld r0, CR
    ldi r1, DSR           ;-- Check DSR to see if ready
    BRzp poll2            ;--   No: poll again
    sti r0, DDR           ;-- send char to display DDR
    add r3, r3, -1        ;-- row--
    BRp disp1

kbLoop:
poll3:
    ldi r1, KBSR          ;-- Check KBSR to see if ready
    BRzp poll3            ;--   No: poll again
    ldi r0, KBDR          ;-- get char from KBDR
poll4:
    ldi r1, DSR           ;-- Check DSR to see if ready
    BRzp poll4            ;--   No: poll again
    sti r0, DDR           ;-- send char to display DDR
    BR kbLoop
done:
    ld  r4, STOP          ;-- Disable sys_clk,
    sti r4, MCR           ;-- shuts down hardware (simulation).

ZERO:  .FILL x0030
NUM24: .FILL #24
NUM80: .FILL #80
CR:    .FILL x000A
LF:    .FILL x000D

poll:
    ldi r1, DSR             ;-- Check DSR to see if ready
    BRzp poll               ;--   No: poll again
    sti r0, DDR             ;--   send char to display DDR, and
    
          STOP:   .FILL x8000    ;-- MCR[15] == 1 (disables sys_clk => shutdown)
         DoneN:   .FILL x0039    ;-- Stop printing chars before '9'
dispLoop:
  	ldi r0,DSR              ;-- wait for a display to be ready
  	BRzp dispLoop           ;-- DSR[15] == 1? no: poll again
	_mov( r0, r1 )          ;-- get char
  	sti r0,DDR              ;-- write char

  	BR kbLoop               ;-- do it again.