Interrupt List Release 61 Last change 16jul00
Copyright (c) 1989-1999,2000 Ralf Brown
Index for interrupt INT 12

Table of Contents by Order
12 - INT 12 - BIOS - GET MEMORY SIZE
12 - INT 12 - CPU-generated (Pentium +) - MACHINE CHECK EXCEPTION
12----CX1806 - INT 12 - KEYBUI v2.0+ - INSTALLATION CHECK
12----CX1807 - INT 12 - PARKER v2.0+ - INSTALLATION CHECK
1205D7BX05D7 - INT 12 U - Borland C++ IDE - INSTALLATION CHECK
124350BX4920 - INT 12 C - CPI-standard virus - "FRIEND" CHECK
12FFFECXFFFE - INT 12 - Back&Forth v1.62+ - API


12 - INT 12 - BIOS - GET MEMORY SIZE
INT 12 - BIOS - GET MEMORY SIZE
Return: AX = kilobytes of contiguous memory starting at absolute address 00000h
Note:	this call returns the contents of the word at 0040h:0013h; in PC and
	  XT, this value is set from the switches on the motherboard
SeeAlso: INT 11"BIOS",INT 2F/AX=4A06h,INT 4C"Tandy 2000",MEM 0040h:0013h

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12 - INT 12 - CPU-generated (Pentium +) - MACHINE CHECK EXCEPTION
INT 12 - CPU-generated (Pentium +) - MACHINE CHECK EXCEPTION
Notes:	Intel documents this interrupt as CPU model-dependent
	for current Pentium processors, the reason for the machine check
	  exception may be read from model-specific registers 00h and 01h
	  (described, for example, in Christian Ludloff's 4P package)
	for Pentium Pro/II processors,	the reason may be read from the
	  MCG_STATUS MSR (see MSR 0000017Ah)
	this exception is enabled by bit 6 of CR4
SeeAlso: INT 11"CPU",MSR 00000000h,MSR 00000001h,MSR 0000017Ah

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12----CX1806 - INT 12 - KEYBUI v2.0+ - INSTALLATION CHECK
INT 12 - KEYBUI v2.0+ - INSTALLATION CHECK
	CX = 1806h
Return: AX = kilobytes of contiguous memory starting at absolute address 00000h
	CX = 1960h if installed
Program: KEYBUI is a resident keyboard driver by Johan Zwiekhorst which allows
	  accented characters and box drawing on standard QWERTY keyboards; it
	  also provides break-to-DOS and screen blanking capabilities
SeeAlso: INT 14/AX=AA01h
Index:	screen saver;KEYBUI

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12----CX1807 - INT 12 - PARKER v2.0+ - INSTALLATION CHECK
INT 12 - PARKER v2.0+ - INSTALLATION CHECK
	CX = 1807h
Return: AX = kilobytes of contiguous memory starting at absolute address 00000h
	CX = 1961h if installed
Program: PARKER is an optionally-resident hard disk parking program by Johan
	  Zwiekhorst

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1205D7BX05D7 - INT 12 U - Borland C++ IDE - INSTALLATION CHECK
INT 12 U - Borland C++ IDE - INSTALLATION CHECK
	AX = 05D7h (1495d)
	BX = 05D7h
Note:	the BC++ IDE will call INT 11/AX=05D7h/BX=0088h if it is loaded
SeeAlso: INT 11/AX=05D7h

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124350BX4920 - INT 12 C - CPI-standard virus - "FRIEND" CHECK
INT 12 C - CPI-standard virus - "FRIEND" CHECK
	AX = 4350h
	BX = 4920h
	CX = AB46h
	DX = 554Eh
Return: if friendly (not to be infected)
	    CX:DX -> ASCIZ identity code (changes yearly)
SeeAlso: INT 13/AX=EC00h"VIRUS",INT 13/AX=5001h,INT 21/AX=0B56h

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12FFFECXFFFE - INT 12 - Back&Forth v1.62+ - API
INT 12 - Back&Forth v1.62+ - API
	AX = FFFEh
	CX = FFFEh
	BX = function
	    00h installation check
		Return: AX = 0001h installed
			     else  not loaded
	    01h (reserved)
	    02h build program ID list (shareware Back&Forth)
		ES:DI -> buffer of at least 100 bytes, to be filled with words
		Return: AX = number of programs defined
			ES:DI buffer filled with AX words
	    02h get memory statistics (Back&Forth Professional)
		Return: AX = available swap memory, KBytes
			BX = maximum task size, KBytes
			DX = fixed overhead per task, excluding video/macro
			      storage
	    03h switch to specified task (task need not be open yet)
		DX = two-letter program ID
		Return: AX = status
			    0000h if task undefined
			    0001h task switch will occur when safe
	    04h (reserved)
	    05h (reserved)
	    06h get version (documented only for Back&Forth Professional)
		Return: AX = version * 100 (v1.71 = 00ABh)
	    07h spawn program (Back&Forth Professional only???)
		ES:DI -> BF_SPAWN record (see #00232)
		Return: AX = status
			    0000h if no task handles free
			    0001h spawn will occur when safe
	    08h get open tasks (documented only for Back&Forth Professional)
		ES:DI -> task info buffer (see #00231,#00233)
		Return: AX = number of open tasks (max 20)
		Note:	the supplied buffer must be large enough to hold 21
			  task entries
	    09h (reserved)
	    ---Back&Forth Professional---
	    0Ah get active clipboard filename
		Return: DX:AX -> ASCIZ clipboard filename
	    0Bh get active task number
		AX = active task number (00h-13h)
		BX = number of tasks allocated
		DX = maximum number of tasks
	    0Ch (reserved)
	    0Dh (reserved)
	    0Eh (reserved)
	    0Fh stuff string into keyboard buffer
		ES:DI -> ASCIZ string to be stuffed
		Return: nothing
	    10h check if in graphics mode
		Return: AX = state
			    0000h color text mode
			    0004h mono text mode
			    FFFFh graphics mode
	    11h get Back&Forth Professional user number
		Return: AX = user number (0000h-00FFh)
	    12h switch task by task number
		DX = task number
		Return: AX = status
			    0000h attempted to switch to active task
			    0001h task switch will occur when safe
			    FFFFh invalid task number
	    13h delete (kill) task
		DX = task number
		Return: AX = status
			    0000h attempted to delete the active task
			    0001h successfully deleted
			    FFFFh invalid task number
		Note:	the active task number will change if the deleted task
			  was lower in the task list than the active task
	    14h get next available task handle
		Return:	AX = next available task handle
			    FFFFh if task table is full
Program: Back & Forth is a task switcher by Progressive Solutions, Inc.
SeeAlso: INT 11/AX=FFFEh
Index:	installation check;BACK&FORTH

Format of Back&Forth task info buffer:
Offset	Size	Description	(Table 00231)
 00h 21 BYTEs	ASCIZ task name
 15h	BYTE	hotkey shift state (as for INT 16/AH=02h)
 16h	WORD	hotkey scan code (see also #00006)
 18h	WORD	program ID
Index:	hotkeys;Back&Forth
SeeAlso: #00232,#00233

Format of Back&Forth Professional BF_SPAWN record:
Offset	Size	Description	(Table 00232)
 00h 21 BYTEs	task description
 15h	BYTE	flag: disable hotkeys
 16h	WORD	environment size in bytes
 18h	BYTE	hotkey shift flags
 19h	WORD	hotkey scancode
 1Bh	WORD	maximum number of EMS pages
 1Dh	WORD	required memory in KBytes
 1Fh  3 BYTEs	DESQview-style two-letter program ID
 22h 13 BYTEs	base name of program to be run (no path or extension)
 2Fh 66 BYTEs	directory from which to start program
 71h 66 BYTEs	initial current directory for program
SeeAlso: #00231,#00233

Format of Back&Forth Professional BF_TASK record:
Offset	Size	Description	(Table 00233)
 00h	DWORD	Unix-style task start time (seconds since 1970/1/1)
 04h 21 BYTEs	task description
 19h	DWORD	elapsed time in task (seconds)
 1Dh	WORD	task ID
 1Fh	BYTE	task hotkey keyboard flags
 20h	WORD	task hotkey scan code (see also #00006)
 22h	DWORD	time task was suspended/exited
 26h	WORD	task handle
SeeAlso: #00231,#00232

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