Int 21H, AH=33H, AL=04H

3.4/4.0

SET CPSW STATE

      AX = 3304h
      DL = new CPSW state

nothing

Notes: this function and AX=3303h were intended to support a proposed

        code-page switching flag (using the WORD at offset 0Ch in the DOS
        directory entry for codepage information); however, this function
        has always been a NOP in public releases of DOS and OS/2.
        See _DOS_Internals_ Chapter 2 for more information.
      the released MS-DOS 4.00 IO.SYS has an undocumented CONFIG.SYS
        directive named CPSW= and that beside others the MS-DOS 4.00 ATTRIB
        supported a number of undocumented special parameters for
        "predefined" Extended Attributes (EAs) e.g.
        ATTRIB filename [(CODEPAGE|CP)[=new_value]].
      this function does not use any of the DOS-internal stacks and may
         thus be called at any time. It is directly dispatched from
         the INT 21h entry point with interrupts disabled.

AX=3303h,AH=11h,AX=5702h

Text based on Ralf Brown Interrupt List Release 61