Row of bombs

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This is a screenshot from an (emulated) Atari ST, the four bombs indicate that the system error "Illegal Instruction" has occurred.

TOS-based systems, such as the Atari ST, used a row of bombs to indicate a critical system error. The number of bombs displayed revealed information about the occurred error. The error (also called an exception) is reported by the Motorola 68000 microprocessor.

• 1 bomb: Reset, Initial PC2
• 2 bombs: Bus Error
• 3 bombs: Address Error
• 4 bombs: Illegal Instruction
• 5 bombs: Zero Divide
• 6 bombs: CHK Instruction
• 7 bombs: TRAPV Instruction
• 8 bombs: Privilege Violation
• 9 bombs: Trace
• 10 bombs: Line 1010 Emulator
• 11 bombs: Line 1111 Emulator
• 12–13 bombs: [unassigned, reserved]
• 14 bombs: Format Error
• 15 bombs: Uninitialized Interrupt Vector
• 16–23 bombs: [unassigned, reserved]
• 24 bombs: Spurious Interrupt
• 25 bombs: Level 1 Interrupt Autovector
• 26 bombs: Level 2 Interrupt Autovector
• 27 bombs: Level 3 Interrupt Autovector
• 28 bombs: Level 4 Interrupt Autovector
• 29 bombs: Level 5 Interrupt Autovector
• 30 bombs: Level 6 Interrupt Autovector
• 31 bombs: Level 7 Interrupt Autovector
• 32–47 bombs: Trap Instruction Vectors
• 48–63 bombs: [unassigned, reserved]
• 64–255 bombs: User Interrupt Vectors

[edit] See also

• Bomb (symbol)

[edit] References

• FAQ for comp.sys.atari.st
• Programmer’s Reference Manual for the Motorola 68000 family