PC Compatible Low-Memory Map (1988)

Report Error and General Enquiry

Michael L. Mohle' Princeton-Galax Systems
9 Grover Ave Princeton, NJ 08540
Source: BEA751

Interrupt Vectors (0000-003F)

AddressIntFunctionAddressIntFunction
000000hCHIP Divide by zero002008hBIOS IRQ_0 Time of day (Vectored Hardware Line)
000401hCHIP Single-step002409hBIOS IRQ_1 Keyboard (Vectored Hardware Line)
000802hCHIP NMI (Non-Maskable-Interrupt)00280AhBIOS IRQ_2 Reserved (Vectored Hardware Line)
000C03hCHIP Breakpoint (1-byte-Interrupt)002C0BhBIOS IRQ_3 Serial port (Vectored Hardware Line)
001004hCHIP Overflow on INTO00300ChBIOS IRQ_4 Serial port (Vectored Hardware Line)
001405hBIOS Print-screen Key | 286 Bound-Check-Failed00340DhBIOS IRQ_5 Alt. printer (Vectored Hardware Line)
001806h286 Undefined Opcode00380EhBIOS IRQ_6 Diskette (Vectored Hardware Line)
001C07h286 No math unit available003C0FhBIOS IRQ_7 Printer (Vectored Hardware Line)
AddressIntFunctionAddressIntFunction
004010hBIOS Video006018hBIOS ROM BASIC entry
004411hBIOS Equipment check006419hBIOS Bootstrap
004812hBIOS Memory size00681AhBIOS Time of day
004C13hBIOS Diskette006C1BhBIOS Keyboard-break
005014hBIOS Serial communications00701ChBIOS Timer-tick
005415hBIOS Cassette, 286 extended I/O00741DhBIOS Video initialization
005816hBIOS Keyboard00781EhBIOS Floppy parameters
005C17hBIOS Printer007C1FhBIOS Graphics Chars (EGA)
AddressIntFunctionAddressIntFunction
008020hDOS Program termination00A028hDOS Internal KEYBOARD_BUSY_LOOP
008421hDOS Function Calls00A429hDOS Internal FAST_PUTCHAR
008822hDOS Terminate Address00A82AhDOS Internal (IRET)
008C23hDOS Ctrl-break Exit00AC2BhDOS Internal (IRET
009024hDOS Critical Error Handler00B02ChDOS Internal (IRET)
009425hDOS Absolute sector read00B42DhDOS Internal (IRET)
009826hDOS Absolute sector write00B82EhDOS Internal EXECUTE-COMMAND
009C27hDOS Terminate, stay resident00BC2FhDOS Multiplex
AddressIntFunctionAddressIntFunction
00C030hDOS Internal (Not a vector! - FAR JMP for CP/M-style calls)0E038hTurbo-C Floating-Point Emulator
00C431hDOS Internal00E439hTurbo-C Floating-Point Emulator
00C832hDOS Reserved (IRET)00E83AhTurbo-C Floating-Point Emulator
00CC33hMicrosoft Mouse00EC3BhTurbo-C Floating-Point Emulator
00D034hTurbo-C Floating-Point Emulator00F03ChTurbo-C Floating-Point Emulator
00D435hTurbo-C Floating-Point Emulator00F43DhTurbo-C Floating-Point Emulator
00D836hTurbo-C Floating-Point Emulator00F83EhTurbo-C Floating-Point Emulator
00DC37hTurbo-C Floating-Point Emulator00FC3FhMS-LINK overlay manager
AddressIntFunctionAddressIntFunction
010040hBIOS (DISK) Floppy-disk handler (relocated INT 13h)012048hBIOS Reserved (IRET)
010441hBIOS (DISK) Primary Fixed-Disk parameters012449hBIOS Reserved (IRET)
010842hBIOS (EGA) Video handler (relocated INT 10h)01284AhBIOS (AT) Real Time Clock Alarm (IRET)
010C43hBIOS (EGA) Initialization parameters012C4BhBIOS Reserved (IRET)
011044hBIOS (EGA) Fonts01304ChBIOS Reserved (IRET)
011445hBIOS Reserved01344DhBIOS Reserved (IRET)
011846hBIOS (DISK) Secondary Fixed-Disk parameters01384EhBIOS Reserved (IRET)
011C47hBIOS Reserved (IRET)013C4FhBIOS Reserved (IRET)
AddressIntFunctionAddressIntFunction
014050hBIOS (AT) Real Time Clock (IRET)016058hBIOS Reserved (IRET)
014451hBIOS Reserved (IRET)016459hBIOS Reserved (IRET)
014852hBIOS Reserved (IRET)01685AhBIOS Reserved (IRET)
014C53hBIOS Reserved (IRET)016C5BhBIOS Reserved (IRET)
015054hBIOS Reserved (IRET)01705ChBIOS Reserved (IRET)
015455hBIOS Reserved (IRET)01745DhBIOS Reserved (IRET)
015856hBIOS Reserved (IRET)01785EhBIOS Reserved (IRET)
015C57hBIOS Reserved (IRET)017C5FhBIOS Reserved (IRET)
AddressIntFunctionAddressIntFunction
018060hUser programs (NULL)01A068hNot used (IRET)
018461hUser programs (NULL)01A469hNot used (IRET)
018862hUser programs (NULL)01A86AhNot used (IRET)
018C63hUser programs (NULL)01AC6BhNot used (IRET)
019064hUser programs (NULL)01B06ChNot used (IRET)
019465hUser programs (NULL)01B46DhNot used (IRET)
019866hUser programs (NULL)01B86EhNot used (IRET)
019867hLIM EMS (User programs)01B86FhNot used (IRET)

AddressIntFunctionAddressIntFunction
01C070hBIOS (AT) IRQ_9 Redirect01E078hNot Used (NULL)
01C471hBIOS (AT) IRQ_10 Redirect01E479hNot Used (NULL)
01C872hBIOS (AT) IRQ_11 Redirect01E87AhNot Used (NULL)
01CC73hBIOS (AT) IRQ_12 Redirect01EC7BhNot Used (NULL)
01D074hBIOS (AT) IRQ_13 Redirect01F07ChNot Used (NULL)
01D475hBIOS (AT) IRQ_14 Redirect01F47DhNot Used (NULL)
01D876hBIOS (AT) INT_87 Redirect01F87EhNot Used (NULL)
01DC77hBIOS (AT) IRQ_15 Redirect01FC7FhNot Used (NULL)
AddressIntFunctionAddressIntFunction
020080hBASIC while in interpreter03DCF7hUser Interrupt (NULL)
03C0F0hBASIC while in interpreter03FCF8hUser Interrupt (NULL)
03C4F1hUser Interrupt (NULL)03E0F8hUser Interrupt (NULL)
03C8F2hUser Interrupt (NULL)03E4F9hUser Interrupt (NULL)
03CCF3hUser Interrupt (NULL)03E8FAhUser Interrupt (NULL)
03D0F4hUser Interrupt (NULL)03ECFBhUser Interrupt (NULL)
03D4F5hUser Interrupt (NULL)03F0FChUser Interrupt (NULL)
03D8F6hUser Interrupt (NULL)03F4FDhUser Interrupt (NULL)
AddressIntFunction
03F8FEhUser Interrupt (NULL) Destroyed on AT in protected mode (Ext. Memory)
03FCFFhUser Interrupt (NULL) Destroyed on AT in protected mode (Ext. Memory)