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open-roms/c64/kernal/reset_entry.s
T

25 lines
740 B
ArmAsm

; Resources describing the C64 reset sequence:
; https://www.c64-wiki.com/wiki/Reset_(Process)
reset_entry:
; The GPL program at https://github.com/Klaus2m5/6502_65C02_functional_tests/blob/master/6502_functional_test.a65
; uses the following initial reset sequence
cld
ldx #$ff
txs
sei
; The following routine is based on reading the public KERNAL jumptable routine
; list, and making unimaginative assumptions about what should be done on reset.
; Initialising IO is obviously required.
jsr ioinit
; Setting up the screen is obviously required
jsr ramtas
; Resetting IO vectors is obviously required, if we want interrupts to run
jsr restor
; What do we do when finished? A C64 jumps into the BASIC ROM
jmp ($a000)