Int 21H [2.25 only] Function 63H (99) Get DBCS lead byte table

Obtains the address of the system table of legal lead byte ranges for double-byte character sets (DBCS), or sets or obtains the interim console flag. Int 21H Function 63H is available only in MS-DOS version 2.25; it is not supported in MS-DOS versions 3.0 and later.

Call with:

AH = 63H

AL = subfunction

00H if getting address of DBCS lead byte table

01H if setting or clearing interim console flag

02H if obtaining value of interim console flag

If AL = 01H

DL = 00H if clearing interim console flag

01H if setting interim console flag

Returns:

If function successful

Carry flag = clear

and, if called with AL = 00H

DS:SI = segment:offset of DBCS lead byte table

or, if called with AL = 02H

DL = value of interim console flag

If function unsuccessful

Carry flag = set

AX = error code

Notes:

The DBCS lead byte table consists of a variable number of two byte entries, terminated by two null (00H) bytes. Each pair defines the beginning and ending value for a range of lead bytes. The value of a legal lead byte is always in the range 80—0FFH.

Entries in the lead byte table must be in ascending order. If no legal lead bytes are defined in a given system, the table consists only of the two null bytes.

If the interim console flag is set, Int 21H Functions 07H (Unfiltered Character Input), 08H (Character Input without Echo), and 0BH (Keyboard Status) will support interim characters.

Unlike most other MS-DOS services, this function call does not necessarily preserve any registers except SS:SP.

[4.0] The address of the DBCS lead byte table can also be obtained with Int 21H Function 65H.