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In the main source file (video.s), after the initialization process and before the OCx interrupt routine, there are two .include directives: The first file, template.inc, is almost empty now, and it is the place where you should write your assembly program. The other one, demo.inc, is only for demonstration and features testing, and may be deleted when it is not needed any more. When you start the demo program (which is by default if you did not modify any file), you shall see a column of help messages at the right of the screen. Pressing F1 sets or removes those messages. Each time when they are set, the portion of the video memory is saved in the special buffer (named AUX_BUFFER in the demo.inc source file) which occupies 700 bytes in the Data RAM, and each time it is removed, the video memory contents are restored from this buffer. So you can call "help screen" without destroying the screen contents. In the similar way, by pressing the PRINT SCREEN key on the keyboard, you can display the whole character set at the bottom of the screen. The previous content of that portion of the screen is saved to (or restored from) the 736-byte AUX_ASCII_BUF.
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Now you can type the text using PS/2 keyboard, change the screen attributes and modes or draw lines and boxes. On the top of the help column, there are cursor parameter markers, named C1 and C2. Here you can see the foreground and background colours for both cursors and which one is currently active. The active cursor determines the attributes for characters typed by the keyboard. To toggle the cursors, press the key TAB. CTRL-R|G|B|C|M|Y|W|K selects the Red|Green|Blue|Cyan|Magenta|Yellow|White|blacK foreground colour for the active cursor. In the similar way, ALT-R|G|B|C|M|Y|W|K selects the background colour. CTRL-X toggles blinking/non-blinking status for the foreground (ALT-X for the background). Each pressing of CAPS LOCK key toggles the bit KBDFLAG,#8, which determines if the CAPS LOCK is active, but the only indication for its status is that the last row, with the text caps on:ATTRIB blinks. When the CAPS LOCK is active, CTRL-key and ALT-key do not alter the cursor parameters, but directly affect the current parameters under the cursor on the screen, leaving the character code unchanged. This can be used to modify the colour and blinking attributes in video memory, without affecting the text contents. |
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Here is the
list of commands for function keys F1...F12:
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