ZST file format

drewsears · Post by **drewsears** » Mon Jun 06, 2005 6:06 am

Hi,

Is there any documentation available on the structure of a ZST file? Specifically, I'm looking to extract the "preview image" of the save; the screenshot taken when the save was created. Is the image data located at a predictable byte offset within the file? Thanks!

Post by **Nach** » Mon Jun 06, 2005 11:39 am

If there is an image present, it will be the last 7168 bytes in the file.

Post by **grinvader** » Mon Jun 06, 2005 3:28 pm

The preview pic is a 64x56x16bpp image. Hence the size.
I *think* it's 565 RGB.

Nightcrawler · Post by **Nightcrawler** » Mon Jun 06, 2005 5:27 pm

This is an open source project. Things like this should be documented in some sort of dev doc somewhere. It really bothers me that ZSNES is open source, but really sucks as an open source project.

Richard C. · Post by **Richard C.** » Mon Jun 06, 2005 6:02 pm

Post by **grinvader** » Mon Jun 06, 2005 7:13 pm

Nightcrawler wrote:This is an open source project. Things like this should be documented in some sort of dev doc somewhere.

Ok, ok: In order...
(What - how big)
Header - header size
5a22 regs and stuff - PH65816regsize
SPC timers - 8 bytes
PPU regs and stuff - 3019 bytes
WRAM - 128kB
VRAM - 64kB
if sound enabled:
# SPC700 RAM and stuff - PHspcsave
# BRR buffer and some DSP stuff - PHdspsave
# DSP memory - size of DSP memory
if ROM has C4 chip:
# C4 WRAM - 8kB
if ROM has SFX/SFX2 chip:
# SFX WRAM - 128kB
# SFX regs status - PHnum2writesfxreg
if ROM has SA1 chip:
# some SA1 regs and stuff - PHnum2writesa1reg
# SA1 RAM - 128kB
# SA1 Status - 3 bytes
# other SA1 regs - 4 bytes
# SA1 dma stuff - 8 bytes
if ROM has DSP-1/2/3/4 chip:
# opcodes status - 2874 bytes
if ROM has SETA chip:
# SETA RAM - 4kB
if ROM has SPC7110 chip:
# SPC7110 WRAM - 64kB
# SPC7110 regs and stuff - PHnum2writespc7110reg
ZSNES emu vars - 227 bytes
SRAM - sram size
preview pic - 7kB