Foenix Kernel Documentation

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Foenix Kernel Documentation

Kernel Essentials

On the FMX, the Foenix Kernel resides in bank $39 of the system RAM. It provides for the initialization of the hardware and a certain minimalist level of access to the hardware. Kernel routines are called through a kernel jump table that starts at $00:1000. All kernel routines must be called using the JSL instruction (long, or 24-bit subroutine call), since they all terminate with an RTL. This allows the kernel routines to be called from anywhere in system memory.

Kernel Calls

Name Address Description
BOOT $00:1000 Cold boot routine
PUTC $00:1018 Print a character to the currently selected channel
Register Width Contents
A 8 ASCII code of the character to print
PUTS $00:101C Print a null-terminated ASCII string to the currently selected channel
Register Width Contents
B 8 Bank containing the data to print
X 16 Address within that bank of the first character to print
SETIN $00:1038 Set the current input channel used by the GET subroutines
Register Width Contents
A 8 Input channel to use
  • 0 = Keyboard
  • 1 = COM1 (external serial)
  • 2 = COM2 (internal serial)
SETOUT $00:103C Set the current output channel used by the PUT subroutines
Register Width Contents
A 8 Input channel to use
  • 0 = Screen
  • 1 = COM1 (external serial)
  • 2 = COM2 (internal serial)
GETCHW $00:104C Get a character from the input channel. Waits until data received. A=0 and Carry=1 if no data is waiting
GETCHE $00:1050 Get a character from the input channel and echo to the screen. Wait if data is not ready.
PRINTCR $00:106C Print Carriage Return
PRINTH $00:1078 Print hex value in memory.
Register Width Contents
B 8 Bank containing the data to print
X 16 Address within that bank of the last byte to print
Y 16 Number of bytes to print
PRINTAH $00:1080 Prints hex value in A. Printed value is 2 wide if M flag is 1, 4 wide if M 0
LOCATE $00:1084 Move the cursor to a new position on the screen.
Register Width Contents
X 16 The column for the cursor
Y 16 The row for the cursor
CSRRIGHT $00:1090 Move the cursor one position to the right
CSRLEFT $00:1094 Move the cursor one position to the left
CSRUP $00:1098 Move the cursor up one row
CSRDOWN $00:109C Move the cursor down one row
CSRHOME $00:10A0 Move the cursor to the upper-left corner
SCROLLUP $00:10A4 Scroll the screen up one line. Creates an empty line at the bottom.
CLRSCREEN $00:10B0 Clear the screen
INITCHLUT $00:10B4 Init character look-up table
INITSUPERIO $00:10B8 Init Super-IO chip
INITKEYBOARD $00:10BC Init keyboard
INITRTC $00:10C0 Init Real-Time Clock
INITCURSOR $00:10C4 Init the Cursors registers
INITFONTSET $00:10C8 Init the Internal FONT Memory
INITGAMMATABLE $00:10CC Init the RGB GAMMA Look Up Table
INITALLLUT $00:10D0 Init the Graphic Engine (Bitmap/Tile/Sprites) LUT
INITVKYTXTMODE $00:10D4 Init the Text Mode @ Reset Time
INITVKYGRPMODE $00:10D8 Init the Basic Registers for the Graphic Mode

Console Special Characters

The console routines support several special control codes for both input and output. When the key on the keyboard is pressed, the associated code is returned by the GET routines. If the code is printed through the PUTC or PUTS, the associated operation will be performed on the screen. Note that this means that any graphics characters associated with those code points will not be displayed by PUTC or PUTS. If those characters must be displayed, they would have to be written to the text memory directly.

Code Name Keyboard Description
$08 BS Backspace Deletes the character to the left of the cursor, pulling characters in from the right.
$09 TAB TAB Moves the cursor right to the next tabulated column (every eight columns).
$0A LF N/A Puts the cursor at column 0 on the next line on the same column.
$0D CR RETURN Creates a newline on the screen. Puts the cursor at column 0 on the next line.
$0F INS Insert Inserts a blank space under the cursor (pushing characters to the right).
$11 UP Up Arrow Moves the cursor up one row.
$1D RIGHT Right Arrow Moves the cursor right one column. May wrap to the next line.
$7F DEL Delete Deletes the character under the cursor, pulling characters in from the right.
$91 DOWN Down Arrow Moves the cursor down one row. May scroll the screen.
$9D LEFT Left Arrow Moves the cursor left one column.

Special Kernel Variables