Index for interrupt INT 0C

Table of Contents by Order
0C - INT 0C C - IRQ4 - SERIAL COMMUNICATIONS (COM1)
0C - INT 0C C - CPU-generated (80286+) - STACK FAULT
0C - INT 0C - IBM SYSTEM 36/38 WORKSTATION EMULATION - API POINTER

INT 0C C - IRQ4 - SERIAL COMMUNICATIONS (COM1)
Desc:	automatically asserted by the UART when COM1 needs attention, if the
	  UART has been programmed to generate interrupts
BUG:	this vector is modified but not restored by Direct Access v4.0, and
	  may be left dangling by other programs written with the same version
	  of compiled BASIC
Notes:	on many PC's, COM3 shares this interrupt
	may be masked by setting bit 4 on I/O port 21h
	DOS 3.3+ revectors IRQ4 to a stack-switching routine unless STACKS=0
	  has been set in CONFIG.SYS.  MS/PC-DOS use the IBM Interrupt Sharing
	  Protocol (see #02568) when hooking this IRQ
SeeAlso: INT 0B"COM2",INT 54"DESQview",INT 5C"DoubleDOS",INT 7C"GO32"

INT 0C C - CPU-generated (80286+) - STACK FAULT
Desc:	this interrupt is generated in protected mode on a stack overflow or
	  underflow, or if an inter-level transition or task switch references
	  a stack segment marked "not present"; it is generated in real mode
	  on accessing a word operand at SS:FFFFh
Note:	the 80286 will shut down in real mode if SP=1 before a push.  On the
	  PC AT and compatibles, external circuitry generates a reset on
	  shutdown.
SeeAlso: INT 0B"CPU",INT 0D"CPU"

INT 0C - IBM SYSTEM 36/38 WORKSTATION EMULATION - API POINTER
Desc:	the IBM System 36/38 emulator may be invoked through a private API,
	  whose entry point address (see #00007) is offset 100h in the segment
	  pointed at by this vector

(Table 00007)
Call the System 36/38 emulator API entry point with:
	AH = function
	    03h update screen
	    05h select next session
		AL = session number (00h-03h)
		Return: AL = session type code
			    00h not active
			    01h display session
			    02h printer session
			    FEh invalid session number
			DS = requested session's data segment (0 if not active)
			    (see #00008)
Return: ???

Format of System 36/38 emulator's data area:
Offset	Size	Description	(Table 00008)
13Eh	BYTE	bit flags for status line indicators turned on since this byte
		last zerod
13Fh	BYTE	bit flags for status line indicators turned off since this
		byte last set to FFh
140h	WORD	offset of EBCDIC to ASCII translation
146h	WORD	offset of EBCDIC screen buffer
148h	WORD	offset of EC (engineering change) level signature
150h	BYTE	"KEYI"
151h	BYTE	5250 key scan code to be sent to remote
15Bh	BYTE	"SYSAV"
15Dh	BYTE	5250 cursor column
15Eh	BYTE	5250 cursor row
167h	BYTE	"DVCTAD"
178h	BYTE	"FLAGS"
184h	BYTE	"SESSNOAD"
193h	BYTE	"STNAD"
198h	BYTE	"NSDS"
Note:	offsets are from the interrupt handler's segment