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Created page with "<pre>;------------------------------------------------------- ; CRTC change colour (fill) test ; with precise timing! ; ; by matahari - (March 27, 2011) ; ; NOTE: Watch the "prec..."
<pre>;-------------------------------------------------------
; CRTC change colour (fill) test
; with precise timing!
;
; by matahari - (March 27, 2011)
;
; NOTE: Watch the "precisely shifted" raster line!
; And, use it wisely to make some filled vectors.
;-------------------------------------------------------
org &3000
run &3000
;------ Switch to Mode 1 -------------------------------
ld a,1
call &bc0e
;------ Set an interrupt that makes nothing! -----------
di
im 1
ld hl,&c9fb
ld (&38),hl
;====== Here comes the MAIN LOOP =======================
Loop: ei
;------ Wait for vertical blanking sync ----------------
ld b,&f5
WaitVB: in a,(c)
rra
jr nc,WaitVB
halt
halt
di
;------ Set the colours --------------------------------
ld bc,&7f00
out (c),c
ld h,&51
ld l,&48
ld d,&43
ld e,&4d
ld a,&44
defs 1127
;------ Here comes copper (sorry, CRTC) list! ----------
REPEAT 4
out (c),h ; Box #1 = GREEN
out (c),l ; Box #2 = RED
out (c),d ; Box #3 = YELLOW
out (c),e ; Box #4 = PURPLE
out (c),h ; Box #5 = GREEN
out (c),l ; Box #6 = RED
out (c),d ; Box #7 = YELLOW
out (c),e ; Box #8 = PURPLE
out (c),h ; Box #9 = GREEN
out (c),l ; Box #10 = RED
defs 25-1 ; Yes, we're using 1 NOP less
; to achieve 8 pixel precision shift
; during next scan !!!
REND
;-------------------------------------------------------
out (c),h ; Box #1 = GREEN
out (c),l ; Box #2 = RED
out (c),d ; Box #3 = YELLOW
out (c),e ; Box #4 = PURPLE
out (c),h ; Box #5 = GREEN
out (c),l ; Box #6 = RED
out (c),d ; Box #7 = YELLOW
out (c),e ; Box #8 = PURPLE
out (c),h ; Box #9 = GREEN
out (c),l ; Box #10 = RED
defs 25 ; NOP
;-------------------------------------------------------
out (c),h ; Box #1 = GREEN
out (c),l ; Box #2 = RED
out (c),d ; Box #3 = YELLOW
out (c),e ; Box #4 = PURPLE
out (c),h ; Box #5 = GREEN
out (c),l ; Box #6 = RED
out (c),d ; Box #7 = YELLOW
out (c),e ; Box #8 = PURPLE
out (c),h ; Box #9 = GREEN
out (c),l ; Box #10 = RED
defs 23 ; Fixing previous subtraction!
;-------------------------------------------------------
REPEAT 5
out (c),h ; Box #1 = GREEN
out (c),l ; Box #2 = RED
out (c),d ; Box #3 = YELLOW
out (c),e ; Box #4 = PURPLE
out (c),h ; Box #5 = GREEN
out (c),l ; Box #6 = RED
out (c),d ; Box #7 = YELLOW
out (c),e ; Box #8 = PURPLE
out (c),h ; Box #9 = GREEN
out (c),l ; Box #10 = RED
defs 24 ; NOP
REND
;-------------------------------------------------------
out (c),a ; Blue space
;-------------------------------------------------------
jp loop
;====== End of MAIN LOOP ===============================
</pre>
; CRTC change colour (fill) test
; with precise timing!
;
; by matahari - (March 27, 2011)
;
; NOTE: Watch the "precisely shifted" raster line!
; And, use it wisely to make some filled vectors.
;-------------------------------------------------------
org &3000
run &3000
;------ Switch to Mode 1 -------------------------------
ld a,1
call &bc0e
;------ Set an interrupt that makes nothing! -----------
di
im 1
ld hl,&c9fb
ld (&38),hl
;====== Here comes the MAIN LOOP =======================
Loop: ei
;------ Wait for vertical blanking sync ----------------
ld b,&f5
WaitVB: in a,(c)
rra
jr nc,WaitVB
halt
halt
di
;------ Set the colours --------------------------------
ld bc,&7f00
out (c),c
ld h,&51
ld l,&48
ld d,&43
ld e,&4d
ld a,&44
defs 1127
;------ Here comes copper (sorry, CRTC) list! ----------
REPEAT 4
out (c),h ; Box #1 = GREEN
out (c),l ; Box #2 = RED
out (c),d ; Box #3 = YELLOW
out (c),e ; Box #4 = PURPLE
out (c),h ; Box #5 = GREEN
out (c),l ; Box #6 = RED
out (c),d ; Box #7 = YELLOW
out (c),e ; Box #8 = PURPLE
out (c),h ; Box #9 = GREEN
out (c),l ; Box #10 = RED
defs 25-1 ; Yes, we're using 1 NOP less
; to achieve 8 pixel precision shift
; during next scan !!!
REND
;-------------------------------------------------------
out (c),h ; Box #1 = GREEN
out (c),l ; Box #2 = RED
out (c),d ; Box #3 = YELLOW
out (c),e ; Box #4 = PURPLE
out (c),h ; Box #5 = GREEN
out (c),l ; Box #6 = RED
out (c),d ; Box #7 = YELLOW
out (c),e ; Box #8 = PURPLE
out (c),h ; Box #9 = GREEN
out (c),l ; Box #10 = RED
defs 25 ; NOP
;-------------------------------------------------------
out (c),h ; Box #1 = GREEN
out (c),l ; Box #2 = RED
out (c),d ; Box #3 = YELLOW
out (c),e ; Box #4 = PURPLE
out (c),h ; Box #5 = GREEN
out (c),l ; Box #6 = RED
out (c),d ; Box #7 = YELLOW
out (c),e ; Box #8 = PURPLE
out (c),h ; Box #9 = GREEN
out (c),l ; Box #10 = RED
defs 23 ; Fixing previous subtraction!
;-------------------------------------------------------
REPEAT 5
out (c),h ; Box #1 = GREEN
out (c),l ; Box #2 = RED
out (c),d ; Box #3 = YELLOW
out (c),e ; Box #4 = PURPLE
out (c),h ; Box #5 = GREEN
out (c),l ; Box #6 = RED
out (c),d ; Box #7 = YELLOW
out (c),e ; Box #8 = PURPLE
out (c),h ; Box #9 = GREEN
out (c),l ; Box #10 = RED
defs 24 ; NOP
REND
;-------------------------------------------------------
out (c),a ; Blue space
;-------------------------------------------------------
jp loop
;====== End of MAIN LOOP ===============================
</pre>
