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remove bg_2 backup routine / free up ram block #396

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remove bg_2 backup routine / free up ram block #396

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Binary file modified patches/ips/vanilla_bugfixes.ips
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1 change: 1 addition & 0 deletions patches/rom_map/Bank 82.txt
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
[unused vanilla code]
8B18 - 8B1F: [free] [unused vanilla code] - 8 bytes
8D51 - 8DBC: [free] [vanilla bg2 code, patched out in vanilla_bugfixes] - 108 bytes
A3D9 - A424: [free] [unused vanilla code] - 76 bytes
B5E8 - B62A: [free] [unused vanilla code] - 67 bytes
B650 - B671: [free] [unused vanilla code] - 34 bytes
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1 change: 1 addition & 0 deletions patches/rom_map/RAM.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@ $7ED823: randomizer-specific event flags:
$0010: metal pirates room door unlocked
$7ED825: pause menu room name enabled (map_area.asm)
$7ed86c: bomb_torizo.asm
$7EDF5C-$7EEF5B: [FREE] (vanilla_bugfixes removes the BG2 backup that used this block of ram.)
$7EF4A0-$7EF4AF: temp storage for special tile (reserve_hud.asm)
$7EF4B0-$7EF4E0: backup of DMA registers in decompression.asm
$7EF4E0-$7EF4E4: pending MSU/SPC playback state (msu1.asm)
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23 changes: 21 additions & 2 deletions patches/src/vanilla_bugfixes.asm
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Expand Up @@ -225,7 +225,7 @@ org $84B7EF ; PLM $B8AC (speed booster escape) LDA $09A4 [$7E:09A4]
; this is due to a missing conditional branch instruction in the vanilla code.
; updated for split_speed compatibility, now fits in vanilla location with external table.
;
; -nn357
; nn_357

org $82ac00
.loop
Expand All @@ -248,4 +248,23 @@ bootstable:
dw $0100, $0200, $2000, $0040, $0080
bootscat:
dw $0003, $0103, $0203, $0203, $0303
assert pc() <= !bank_82_free_space_end
assert pc() <= !bank_82_free_space_end

; Pause menu tiles routine DMA transfer size bug fix.
; Vanilla code transfers too many bytes, destroying the BG2 tilemap.
; Correcting the DMA transfer size means the backup/restore BG2 pause hook isn't needed.
; Which also frees up the 4k block of ram used for the backup / restore.
; nn_357

;org $828ed2 ; Correct DMA transfer size $1000, [hud_expansion_opaque already fixes this, included for reference].
; db $10

org $828d08 ; Back up BG2 tilemap for pause menu
bra +
nop
+

org $829377 ; Restore BG2 tilemap from pause menu
bra +
nop
+
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