Skip to content

Take the freeze slot number in the byte order the code actually uses #944

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
mlund wants to merge 1 commit into
base: development
Choose a base branch
from
Open

Take the freeze slot number in the byte order the code actually uses #944

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
31 changes: 21 additions & 10 deletions src/hyppo/syspart.asm
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -237,6 +237,8 @@ syspart_configsector_apply_trap:
sta hypervisor_enterexit_trigger

syspart_unfreeze_from_slot_trap:
;; Only X needs restoring: the dispatch above clobbers it with tax,
;; while Y arrives from the caller untouched.
ldx hypervisor_x
jsr syspart_locate_freezeslot
jsr unfreeze_load_from_sdcard_immediate
Expand Down Expand Up @@ -278,8 +280,13 @@ syspart_locate_freezeslot_trap:

syspart_locate_freezeslot:
;; Get the first sector of a given freeze slot
;; X = low byte of slot #
;; Y = high byte of slot #
;; X = high byte of slot #
;; Y = low byte of slot #
;;
;; The slot number is pushed here and popped back below in the same
;; order, which swaps the pair: plx takes what phy pushed. So the
;; multiply reads its low byte from Y, and freeze_to_slot in freeze.asm
;; documents the same order ("Slot in XXYY").

phx
phy
Expand All @@ -288,21 +295,25 @@ syspart_locate_freezeslot:
lda syspart_present
bne splf1
lda #syspart_error_nosyspart
sta syspart_error_code
clc
rts
bra slotfail
splf1:
;; Check that freeze slot number is not invalid
cpy syspart_freeze_slot_count+1
beq sc1
;; Check that freeze slot number is not invalid.
;; High byte first; only when it matches does the low byte decide.
cpx syspart_freeze_slot_count+1
bcc slotnumok
sc1: cpx syspart_freeze_slot_count+0
beq slotbad
bne slotbad
cpy syspart_freeze_slot_count+0
bcc slotnumok
slotbad:
;; Report error status for out of bounds slot number
lda #syspart_error_badslotnum
slotfail:
;; Both error paths leave through here, because the slot number is
;; still on the stack from the phx/phy above and returning without it
;; would take the caller's return address with it.
sta syspart_error_code
plx
plx
clc
rts

Expand Down