Files
alttpr-baserom/save.asm
cassidoxa 09d15f3294 Another WRAM label pass
Deleted compression.asm
2022-11-22 00:36:39 -05:00

219 lines
8.2 KiB
NASM

;--------------------------------------------------------------------------------
WriteSaveChecksumAndBackup:
LDX.w #$0000 : TXA : - ; Checksum first $04FE bytes
CLC : ADC.l SaveDataWRAM, X
INX #2
CPX.w #$04FE : BNE -
LDX.w #$0000 : - ; Checksum extended save data
CLC : ADC.l ExtendedFileNameWRAM, X
INX #2
CPX.w #$0FFE : BNE -
STA.b Scrap00
LDA.w #$5A5A
SEC : SBC.b Scrap00
STA.l InverseChecksumSRAM
PHB
LDA.w #$14FF ; \
LDX.w #CartridgeSRAM&$FFFF ; | Copies $1500 bytes from beginning of cart SRAM to
LDY.w #SaveBackupSRAM&$FFFF ; | $704000
MVN !SRAMBank, !SRAMBank ; /
PLB
RTL
;--------------------------------------------------------------------------------
ValidateSRAM:
REP #$30
LDX.w #$0000 : TXA : - ; Checksum first $04FE bytes
CLC : ADC.l CartridgeSRAM, X
INX #2
CPX.w #$04FE : BNE -
LDX.w #$0000 : - ; Checksum extended save data
CLC : ADC.l ExtendedFileNameSRAM, X
INX #2
CPX.w #$0FFE : BNE -
STA.b Scrap00
LDA.w #$5A5A
SEC : SBC.b Scrap00
CMP.l InverseChecksumSRAM : BEQ .goodchecksum
LDX.w #$0000 : TXA : - ; Do the same for the backup save
CLC : ADC.l SaveBackupSRAM, X
INX #2
CPX.w #$04FE : BNE -
LDX.w #$0000 : -
CLC : ADC.l SaveBackupSRAM+$500, X
INX #2
CPX.w #$0FFE : BNE -
STA.b Scrap00
LDA.w #$5A5A
SEC : SBC.b Scrap00
CMP.l SaveBackupSRAM+$4FE : BEQ +
TDC : STA.l FileValiditySRAM ; Delete save by way of zeroing validity marker
BRA .goodchecksum : +
PHB
LDA.w #$14FF ; \
LDX.w #SaveBackupSRAM&$FFFF ; | Copies $1500 bytes from backup on cart SRAM to
LDY.w #CartridgeSRAM&$FFFF ; | main save location at $700000
MVN !SRAMBank, !SRAMBank ; /
PLB
.goodchecksum
LDX.w #$00FE : - ; includes prize pack reset after save and quit
STZ.w $0D00, X
STZ.w $0E00, X
STZ.w $0F00, X
DEX #2
BPL -
SEP #$30
RTL
;--------------------------------------------------------------------------------
ClearExtendedSaveFile:
STA.l $700400, X ; what we wrote over
STA.l $700500, X
STA.l $700600, X
STA.l $700700, X
STA.l $700800, X
STA.l $700900, X
STA.l $700A00, X
STA.l $700B00, X
STA.l $700C00, X
STA.l $700D00, X
STA.l $700E00, X
STA.l $700F00, X
STA.l $701000, X
STA.l $701100, X
STA.l $701200, X
STA.l $701300, X
STA.l $701400, X
; Clear backup save
STA.l $704000, X
STA.l $704100, X
STA.l $704200, X
STA.l $704300, X
STA.l $704400, X
STA.l $704500, X
STA.l $704600, X
STA.l $704700, X
STA.l $704800, X
STA.l $704900, X
STA.l $704A00, X
STA.l $704B00, X
STA.l $704C00, X
STA.l $704D00, X
STA.l $704E00, X
STA.l $704F00, X
STA.l $705000, X
STA.l $705100, X
STA.l $705200, X
STA.l $705300, X
STA.l $705400, X
RTL
;--------------------------------------------------------------------------------
ClearExtendedWRAMSaveFile:
STA.l $7EF400, X ; what we wrote over
STA.l $7F6000, X
STA.l $7F6100, X
STA.l $7F6200, X
STA.l $7F6300, X
STA.l $7F6400, X
STA.l $7F6500, X
STA.l $7F6600, X
STA.l $7F6700, X
STA.l $7F6800, X
STA.l $7F6900, X
STA.l $7F6A00, X
STA.l $7F6B00, X
STA.l $7F6C00, X
STA.l $7F6D00, X
STA.l $7F6E00, X
STA.l $7F6F00, X
RTL
;--------------------------------------------------------------------------------
CopyExtendedSaveFileToWRAM:
PHA
SEP #$30
LDA.w DMAP0 : PHA ; preserve DMA parameters
LDA.w BBAD0 : PHA ; preserve DMA parameters
LDA.w A1T0L : PHA ; preserve DMA parameters
LDA.w A1T0H : PHA ; preserve DMA parameters
LDA.w A1B0 : PHA ; preserve DMA parameters
LDA.w DAS0L : PHA ; preserve DMA parameters
LDA.w DAS0H : PHA ; preserve DMA parameters
;--------------------------------------------------------------------------------
STZ.w NMITIMEN ; Disable NMI, V/H, joypad
STZ.w HDMAEN ; Disable HDMA
LDA.b #$00 : STA.w DMAP0 ; set DMA transfer direction A -> B, bus A auto increment, single-byte mode
LDA.b #$80 : STA.w BBAD0 ; set bus B source to WRAM register
LDA.b #$00 : STA.w WMADDL ; set WRAM register source address
LDA.b #$60 : STA.w WMADDH
LDA.b #$7F : STA.w WMADDB
STZ.w A1T0L ; set bus A destination address to SRAM
LDA.b #$05 : STA.w A1T0H
LDA.b #$70 : STA.w A1B0
LDA.b #$00 : STA.w DAS0L ; set transfer size to 0x1000
LDA.b #$10 : STA.w DAS0H ; STZ DAS0B
LDA.b #$01 : STA.w MDMAEN ; begin DMA transfer
LDA.b #$81 : STA.w NMITIMEN ; Re-enable NMI and joypad
;--------------------------------------------------------------------------------
PLA : STA.w DAS0H ; restore DMA parameters
PLA : STA.w DAS0L ; restore DMA parameters
PLA : STA.w A1B0 ; restore DMA parameters
PLA : STA.w A1T0H ; restore DMA parameters
PLA : STA.w A1T0L ; restore DMA parameters
PLA : STA.w BBAD0 ; restore DMA parameters
PLA : STA.w DMAP0 ; restore DMA parameters
REP #$30
PLA
STA.l $7EC00D ; what we wrote over
RTL
;--------------------------------------------------------------------------------
CopyExtendedWRAMSaveFileToSRAM:
PHA
PHB
SEP #$30
LDA.b #$00 : PHA : PLB
LDA.w DMAP0 : PHA ; preserve DMA parameters
LDA.w BBAD0 : PHA ; preserve DMA parameters
LDA.w A1T0L : PHA ; preserve DMA parameters
LDA.w A1T0H : PHA ; preserve DMA parameters
LDA.w A1B0 : PHA ; preserve DMA parameters
LDA.w DAS0L : PHA ; preserve DMA parameters
LDA.w DAS0H : PHA ; preserve DMA parameters
;--------------------------------------------------------------------------------
STZ.w NMITIMEN ; Disable NMI, V/H, joypad
STZ.w HDMAEN ; Disable HDMA
LDA.b #$80 : STA.w DMAP0 ; set DMA transfer direction B -> A, bus A auto increment, single-byte mode
STA.w BBAD0 ; set bus B source to WRAM register
LDA.b #$00 : STA.w WMADDL ; set WRAM register source address
LDA.b #$60 : STA.w WMADDH
LDA.b #$7F : STA.w WMADDB
STZ.w A1T0L ; set bus A destination address to SRAM
LDA.b #$05 : STA.w A1T0H
LDA.b #$70 : STA.w A1B0
LDA.b #$10 : STA.w DAS0L ; set transfer size to 0xB00
LDA.b #$0B : STA.w DAS0H ; STZ DAS0B
LDA.b #$01 : STA.w MDMAEN ; begin DMA transfer
LDA.b #$81 : STA.w NMITIMEN; Re-enable NMI and joypad
;--------------------------------------------------------------------------------
PLA : STA.w DAS0H ; restore DMA parameters
PLA : STA.w DAS0L ; restore DMA parameters
PLA : STA.w A1B0 ; restore DMA parameters
PLA : STA.w A1T0H ; restore DMA parameters
PLA : STA.w A1T0L ; restore DMA parameters
PLA : STA.w BBAD0 ; restore DMA parameters
PLA : STA.w DMAP0 ; restore DMA parameters
REP #$30
PLB
PLA
RTL