You need tools to develop for the Saturn, here they are
Saturn Compiler / Libraries
SaturnOrbit
: The all-in-one installer for SEGA Saturn development
K P I T GNU Tools & Support
: Pre-built binary toolchains packaged in ready to use Windows & Linux Installers
Saturn Compiler (Cygnus v.2.7)
Hitachi Compiler (from a DC dev kit)
Saturn Forth Compiler
S.N. Systems ASSH & ASMSH
Psy-Q Tools
SGL Libraries
SBL Libraries
TrueMotion Libraries
: TrueMotion(R) S Developer Disk for Sega Saturn
Rockin'B Libraries for Saturn, Windows, MacOS X
: Development libs for Saturn, partially platform independent
CyberWarriorX's CDC Library
: Reverse-engineering of the Sega's CDC library
Elbesem Engine
: Zaksund's Toolkit
Pro Action Replay Tools
Ex-Cyber's PAR firmware replacement/upgrade tool
Saturn Action Replay Plus / Game Shark PC Comms Software (includes ROM 2.02)
Saturn Action Replay Plus / Game Shark PC Comms Software (includes ROM 2.01)
Saturn Action Replay / Game Shark PC Comms Software (includes ROM 1.94)
Saturn Action Replay / Game Shark PC Comms Software (includes ROM 1.81)
Freewing SSLink
Saturn File Executor for Windows 95
-
(source)
Saturn Memory Dump for Windows 95
Tyranid's Saturn Debugger
Debugger - DOS Source
Debugger - Linux Source
Saturn PAR utility
VDP1 Framebuffer Viewing Utility
Saturn Graphic Tools
Sega Graphic Tools for Windows 95
: Sega Saturn monitor, 3D editor, Map editor
Sega Graphic Tools for MacOS
SGA3 Tools
: SGA3 viewer and SGA3 plugin for Photoshop
Micronet 3D Atelier
: Nice 3D tool with a good Data Converter (Generates DXF Polyline & DXF 3DFace)
Rockin'B Saturn DXF tool
: Improves DXF compatibility for DXF2SG3.exe of the SS-SDK
To Sega Saturn (TOSS)
: Converts graphic files to Sega Saturn .CEL, .MAP and .PAL files
Background Gfx Converter
: The Saturn VDP2 Background Converter
S2D->RAW Converter
PCX->Saturn Converter
: PCXToSat converts 8 bit PCX files to 8 bit bitmap scroll plane files for the Saturn. PCXToSat can output a binary or C file
BIT->BMP Converter
: Sega Saturn CG Converter 1.0
Taktools
: Takashi's image dumping tools
Sega Saturn picture viewer
: Sega Saturn Pretty Sammy image viewer
Saturn Audio Tools
WAV ->PCM & .C And PCM->WAV Converter
SoundPlayer
ADPCM Encoder
AIFF to Redbook converter
Sound Tools
Saturn Video Tools
AVI->CPK Encoder (aka AviToSaturn)
TrueMotion Encoder
TrueMotion Decoder for Windows 95
TrueMotion Player TmPlay.exe Ver 1.22
Another Converter from CPK to AVI
ACPK2AVI Helper(acpkHPR)
Winvdt2 - A saturn video viewer and converter (User name : Free Use , Pass : ZUICSG)
Cinepak viewer
Cinepak - CAK - ADX Converter & ADX Player
Cinepak Parser for ActiveMovie/DirectShow
Cinepak->VfW AVI Converter 1.00
Cinepak->VfW AVI Converter 0.08
Cinepak->AVI
Cinepak->WAV
PAK file reader & converter
Other Tools
FDD Operator
: CD rip of the Saturn Floppy Disk driver
Virtual CD software
: Includes tools for building disc images
CyberWarriorX's Bininfo
: Returns info about Saturn binaries