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pt3: make interrupt handlers consistent

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This commit is contained in:
Vince Weaver 2019-06-07 16:56:41 -04:00
parent 0efd367bfa
commit 8168a2721f
2 changed files with 18 additions and 1 deletions
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11
pt3_lib/interrupt_handler.s
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@ -10,9 +10,18 @@
; It then calculates if it is a BRK or not (which trashes A)
; Then it sets up the stack like an interrupt and calls 0x3fe
; Note: the IIc is much more complicated
; its firmware tries to decode the proper source
; based on various things, including screen hole values
; we bypass that by switching out ROM and replacing the
; $fffe vector with this, but that does mean we have
; to be sure status flag and accumulator set properly
TIME_OFFSET EQU 13
interrupt_handler:
php ; save status flags
pha ; save A ; 3
; A is saved in $45 by firmware
txa
@ -147,10 +156,10 @@ exit_interrupt:
tax ; restore X
pla ; restore a ; 4
; on II+/IIe (but not IIc) we need to do this?
interrupt_smc:
lda $45 ; restore A
plp
rti ; return from interrupt ; 6

8
pt3_player/interrupt_handler.s
View File

@ -10,6 +10,14 @@
; It then calculates if it is a BRK or not (which trashes A)
; Then it sets up the stack like an interrupt and calls 0x3fe
; Note: the IIc is much more complicated
; its firmware tries to decode the proper source
; based on various things, including screen hole values
; we bypass that by switching out ROM and replacing the
; $fffe vector with this, but that does mean we have
; to be sure status flag and accumulator set properly
TIME_OFFSET EQU 13
interrupt_handler: