Sharp MZ-800 - (6) Restoring initial settings; (7) Logical summing of colours

10 INIT “‘CRT:M2,B1'" — Mode 2, palette block No. =1
20 PAL 4,12 — Assigns colour code 12 to palette code 4.
30 PAL 5,10 — Assigns colour code 10 to palette code 5.
40 PAL 6,8 — Assigns colour code 8 to palette code 6.
50 PAL 7,6 — Assigns colour code 6 to palette code 7.
After executing the above program,
LINE [5,0] 10,20,100,50
draws a line in light red. In this case, the first parameter is recognized we palette code.
LINE [1,0] 10,20,100,50
Draws the same line in blue. In this case, the first parameter is recognized as a colour code.
INIT “‘CRT:BO"’
If the above command is executed after execution of the above program, the result is different.
LINE [5,0] 10,20,100,50
Draws the line in cyan. In this case, the first parameter is recognized as a colour code.
LINE [1,0] 10,20,100,50
Draws the line in blue. In this case, the first parameter is recognized as a palette code. When INIT
“CRT:BO”’ is executed, the palette codes which can be set are changed as shown below.
The initial settings of the colour code assignments are assumed.
Palette code Palette code
5 0
6 INIT ‘‘CRT:B0" 1
i ———- 2
8 3
(6) Restoring initial settings
Executing the INIT statement to set a new display mode restores the initial settings of the colour code.
Executing the INIT statement to set a new palette block in the 16-colour mode also restores the initial
settings.
(7) Logical summing of colours
Some graphic statements such as COLOR, SET and LINE use the ‘‘mode’’ parameter.
When the mode parameter is specified as 0, the resultant colour is specified by the palette code parameter.
When the mode parameter is specified as 1, a logical OR operation is performed between the existing
palette code for a dot (on the screen) and the new specified palette code for the same dot, to produce
the resultant colour. For example, if the existing palette code for a dot at (50,50) is 2 and the new
specified palette code is 1, the resultant palette code is 3.
0010 (binary for 2) OR 0001 (binary for 1) - 0011 (binary for 3)
A-S