Atari 400 Technical Reference Manual page 178

The base addresses of the Handler vectors for the resident
handlers are shown below:
Screen Editor (E)
Display Handler (5)
Keyboard Handler (K)
Printer Handler (P)
Cassette Handler (C)
E400
E410
E420
E430
E440
See Section 5 for the format of the entry for each Handler.
The 6502 Computer interrupt vector values are shown below:
Function Address
Value
NMI FFFA E7B4
RESET FFAC
E477
IRG FFFE
E6FE
OPERATING SYSTEM C016555 -- Appendix
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