Int D4 Fn 2A  - Pc-mos/386 V5.01 - Swap Control Block Data Of Scb Or Tcb   [O]

   AH = 2Ah
   BX = offset into control block at which to start swap
   CX = number of bytes to swap
   DX = segment/selector of control block obtained via AH=26h or AH=27h
   DS:SI -> buffer containing new data and to receive current data

Return: CF clear if successful
   CF set on error
       AX = error code (see also #1366 at INT 21/AH=59h/BX=0000h)
       05h access denied due to an invalid segment/selector

Note:  the interrupts are disabled during the swap to prevent corruption

See Also: AH=26h,AH=27h,AH=28h,AH=29h