However, what you actually have is something like this:
The programmable characters which make up the bit map are arranged in 25 rows of 40 columns each. While this is a good method of organization for text, it makes bit mapping somewhat difficult. (There is a good reason for this method. See the section on MIXED MODES.)
The following formula will make it easier to control a dot on the bit map screen:
The start of the display memory area is known as the BASE, The row number (from 0 to 24) of your dot is:
ROW = INT(Y/8) (There are 320 bytes per line.)The character position on that line (from 0 to 39) is:
CHAR = INT(X/8) (There are 8 bytes per character.)The line of that character position (from 0 to 7) is:
LINE = Y AND 7
This page has been created by Sami Rautiainen. | |
Read the small print. | Last updated May 12, 2002. |