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SRAM Expansion Patch (32Kb)
SRAM Expansion
by madsiur
version 1.0
released on 05/25/2018
apply to headerless FF3us 1.0 ROM
wiki entry
download
Description
This hack expand SRAM by $1600 bytes for each save slot, allowing now 8Kb bytes for each save slot plus a third 8Kb for general purpose for a total of 32Kb of SRAM. In original game, only 8Kb of SRAM is used ($306000-$307FFF), each slot occupying $0A00 bytes and $200 bytes for general purpose at the end of the 8Kb block.
With this hack, $306000-$307FFF is used for slot 1, $316000-$317FFF for slot 2 and $326000-$327FFF for slot 3. $336000-$337FFF is used for game SRAM. When you play the game, $7E1600-$7E1FFF is still used and copied to correct slot at saving. $336000-$3375FF is copied to correct slot as extra SRAM. At game loading, correct slot is loaded into $336000-$3375FF and $7E1600-$7E1FFF. So in order to save or load from extra SRAM in your hack, use as an example STA $336000,X or LDA $336000,X.
Since $337600-$337EFF is not used, it means it could be use as scratchpad SRAM for temporary things or have a general use common to the three slots. $337FF0-$337FFF has same function as the original $307FF0-$307FFF.
SRAM could be expanded more but I figured a whole $2000 bytes instead of $0A00 is enough expansion for any hack. In HiROM mapping banks $20-$3F can be used to map SRAM, using always the $6000-$7FFF range of the bank. $C0FFD8 tell the emulator the SRAM size of the ROM.
I have not tested this on sd2snes, everdrive or real hardware. snes9x 1.55 and bsnes+ were used for testing. If you plan to use this hack and make a cart of your hack after, you will need a HiROM cart with a 32Kb memory chip. I have no idea if any existing SNES game has already 32Kb of SRAM.
SRAM map
by madsiur
version 1.0
released on 05/25/2018
apply to headerless FF3us 1.0 ROM
wiki entry
download
Description
This hack expand SRAM by $1600 bytes for each save slot, allowing now 8Kb bytes for each save slot plus a third 8Kb for general purpose for a total of 32Kb of SRAM. In original game, only 8Kb of SRAM is used ($306000-$307FFF), each slot occupying $0A00 bytes and $200 bytes for general purpose at the end of the 8Kb block.
With this hack, $306000-$307FFF is used for slot 1, $316000-$317FFF for slot 2 and $326000-$327FFF for slot 3. $336000-$337FFF is used for game SRAM. When you play the game, $7E1600-$7E1FFF is still used and copied to correct slot at saving. $336000-$3375FF is copied to correct slot as extra SRAM. At game loading, correct slot is loaded into $336000-$3375FF and $7E1600-$7E1FFF. So in order to save or load from extra SRAM in your hack, use as an example STA $336000,X or LDA $336000,X.
Since $337600-$337EFF is not used, it means it could be use as scratchpad SRAM for temporary things or have a general use common to the three slots. $337FF0-$337FFF has same function as the original $307FF0-$307FFF.
SRAM could be expanded more but I figured a whole $2000 bytes instead of $0A00 is enough expansion for any hack. In HiROM mapping banks $20-$3F can be used to map SRAM, using always the $6000-$7FFF range of the bank. $C0FFD8 tell the emulator the SRAM size of the ROM.
I have not tested this on sd2snes, everdrive or real hardware. snes9x 1.55 and bsnes+ were used for testing. If you plan to use this hack and make a cart of your hack after, you will need a HiROM cart with a 32Kb memory chip. I have no idea if any existing SNES game has already 32Kb of SRAM.
SRAM map
Code:
Slot 1 expansion: $306A00-$307FFF
$306000-$3069FF = $7E1600-$7E1FFF
Slot 2 expansion: $316A00-$317FFF
$316000-$3169FF = $7E1600-$7E1FFF
Slot 3 expansion: $326A00-$327FFF
$326000-$3269FF = $7E1600-$7E1FFF
Other SRAM values: $336000-$3375FF (game common SRAM)
$337600-$337EFF (unused)
$337F00 = last altered savefile
$337F01 = rng index
$337F08 = fixed value #$E41B (slot 1)
$337F0A = fixed value #$E41B (slot 2)
$337F0C = fixed value #$E41B (slot 3)
$337F0E = fixed value #$E41B (slot 4, useless..)
The following 7 users say Thank You to madsiur for this post:
• Gi Nattak (05-25-2018), JWhiteLXXXIX (06-03-2019), NPCnextdoor (07-07-2018), Robo Jesus (06-04-2018), SSJ Rick (05-25-2018), Tenkarider (05-25-2018), Warrax (05-25-2018)
• Gi Nattak (05-25-2018), JWhiteLXXXIX (06-03-2019), NPCnextdoor (07-07-2018), Robo Jesus (06-04-2018), SSJ Rick (05-25-2018), Tenkarider (05-25-2018), Warrax (05-25-2018)
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