rom4x/rom5x/B1_C53D_patch_out_rom_cksum.s
2017-03-18 20:00:43 -07:00

14 lines
431 B
ArmAsm

; Patch the Apple IIc+ diagnostics to skip the ROM checksum test.
; We should really examine the routine at $D249 in the aux firmware
; to see if we can calculate a new checksum.
; the $D249 routine copies a small routine into the zero page that
; calculates the checksum. It returns with carry set = error and
; carry clear = OK. So we just patch the JSR to always clear the
; carry. For now.
.code
.org $C53D
nop
nop
clc