ANSI Support

As of v0.4 of the kernel, the PUTC function now supports printing to the EVID expansion card and ANSI style control sequences.

Printing to the EVID Screen

If the EVID card is installed, the EVID screen is available on channel #4. To print text to the EVID screen, use the SETOUT kernel routine to set the channel to 4 and then call PUTC or any routine that uses PUTC to print. The characters will be printed to the EVID screen. To go back to printing to the main screen, use SETOUT to set the channel to 0.

Note that the EVID screen and the main screen are completely independent. They can be used at different resolutions and with different border sizes. Also they have independent cursors and terminal state (e.g. current printing color).

ANSI Escape Codes

PUTC will do some elementary interpretation of ANSI or VT style escape codes to control the screen. The codes can be used with either screen. The following escape sequences are supported:

Escape	Name	Purpose
CSI n @	ICH	Inserts n (default: 1) blank characters, starting at the cursor.
CSI n A	CUU	Move the cursor up n (default: 1) rows.
CSI n B	CUD	Move the cursor down n (default: 1) rows.
CSI n C	CUF	Move the cursor forward n (default: 1) positions.
CSI n D	CUB	Move the cursor back n (default: 1) positions.
CSI n;m H	CUP	Move the cursor to position (n, m) on the screen... home position of (1, 1) if no parameters provided.
CSI n J	ED	Erase part or all of the screen, based on n. If n is 0 or missing, clear from the cursor to the end of the screen. If n is 1, erase from the beginning of the screen to the cursor. If n is 2, erase the entire screen.
CSI n K	EL	Erase part or all of the current line, based on n. If n is 0 or missing, clear from the cursor to the end of the line. If n is 1, erase from the beginning of the line to the cursor. If n is 2, erase the entire line.
CSI n P	DCH	Deletes n (default: 1) characters starting at the cursor.
CSI n h	SM	Sets terminal modes (see table below).
CSI n l	RM	Resets terminal modes (see table below).
CSI n m	SGR	Sets the appearance of the characters to be printed next (see table below).

SGR Support

The support for the standard SGR codes is somewhat limited in the Foenix kernel, due to limitations in the text mode screen. Here are the codes the kernel supports:

Code	Purpose
1	Set the foreground to high intensity
2	Go back to normal intensity
7	Enable reversed text
22	Go back to normal intensity
27	Stop inverting the colors
30..37	Set the foreground color
39	Restore the default foreground color
40..47	Set the background color
49	Restore the default background color

Mode Support

There are only two modes that can be set or reset:

• 25 will show (set) or hide (reset) the cursor.
• 28 will enable (set) or disable (reset) the processing of the PAUSE/BREAK key.

If processing is disabled, the TESTBREAK kernel routine will not return if the PAUSE/BREAK key has been pressed. The key will be ignored until re-enabled.