Specifications

AMD Geode™ GeodeROM Functional Specification 189
Video BIOS Support
32087C
13.1.20 Function 13h - Write String
Description:
Sends a string to the display using the same TTY side-effects as Function 0Eh. With string types of
AL = 2 and AL = 3, the TTY control commands are not followed by an attribute since they are not printable characters.
Several control characters have an effect on the cursor position without writing an actual character to the display. The
bell character (ASCII 07h) beeps the speaker once without changing the cursor position. The backspace character
(ASCII 08h) moves the cursor back one position on the line unless the cursor is already at the beginning of the line. At
that point the backspace has no effect. The line feed character (ASCII 0Ah) moves the cursor down one row without
changing the column position. If the cursor is already at the bottom of the screen, then the display scrolls up one line.
The carriage return (ASCII 0Dh) moves the cursor position to the beginning of the current line.
String Types
(AL = ?) Descriptions
00h Write character string without moving the cursor. Attribute is in BL.
01h Write character string and update the cursor position. Attribute is in BL.
02h Write character string without moving the cursor. Attributes are embedded in string.
03h Write character string and update the cursor position. Attributes are embedded in string.
Passed:
Returns:
None.
Parameter Description
AH 13h = Function number
AL String Type:
0 = Constant attribute, cursor not moved
1 = Constant attribute, cursor moved
2 = String includes attributes, cursor not moved
3 = String includes attributes, cursor moved
BL Attribute (for string types 0 and 1)
BH Page Number
CX Character Count
DL Cursor column to start
DH Cursor row to start
DS Seg0
ES:BP Pointer to character string