sam: add a cursor

diff --git a/Kernel/platform-sam/sam_vt.s b/Kernel/platform-sam/sam_vt.s
index 9b8ae60..d681195 100644 (file)
--- a/Kernel/platform-sam/sam_vt.s
+++ b/Kernel/platform-sam/sam_vt.s
@@ -222,10 +222,50 @@ _vtwipe:
 ;      TODO
 ;
 _cursor_on:
-_cursor_off:
+       pop hl
+       pop de
+       push de
+       push hl
+       call base_addr
+       ex de,hl
+       inc h           ; Move on 6 scan lines
+       inc h           ; So the cursor is bottom 2
+       inc h
+       ld (cursorpos),hl
+       jr xor_cursor
+;
+;      Remove our cursor
+;
 _cursor_disable:
+_cursor_off:
+       ld hl,(cursorpos)
+       ld a,h
+       inc a
+       ret z
+       ld a,#255
+       ld (cursorpos),a
+xor_cursor:
+       call map_video
+       call xorhl
+       ld de,#127
+       add hl,de
+       call xorhl
+       jp unmap_video
+
+xorhl:
+       ld a,(hl)
+       cpl
+       ld (hl),a
+       inc hl
+       ld a,(hl)
+       cpl
+       ld (hl),a
+       ret
+
 _vtattr_notify:
        ret
 
 colours:
        .word 0
+cursorpos:
+       .word 0xFFFF