BS-X Satellaview Header

The header will be at 0x7xxx (for LoROM) or 0xFxxx (for HiROM) for the downloaded content. There may be more than one in a single Memory Pack.

xFB0-xFB1 = Licensee / Maker Code
xFB2-xFB5 = Program Type
xFB6-xFBF = Reserved
xFC0-xFCF = Title
xFD0-xFD3 = Block Allocation ...

Writing the Header

[[!redirects Writing the Header]] Before writing your actual program's code, you need a header to describe WLA the SNES' memorymap. This is basically just a file you will include into your source. It contains all of the basic information about your ROM. The following is a basic header file for a 2 ...

Using the NMI-VBLANK

Earlier we made an interrupt table which assigned addresses for the SNES interrupts. We assigned the address to an empty handler that just returned for every interrupt except the NMI (VBLANK) interrupt. This interrupt occurs whenever the T.V.'s tracer is not tracing to the screen, making it safe to ...

ASM Hacking for Dummies

[[!include asm_hacking_sidebar]]

Introduction ### {: #introduction}

This document was written for the aspiring ROM hacker with little to no experience in 65c816 programming. The basics have been thoroughly covered and I believe this should prove a significant aid to anyone interested in 65c8 ...


This is a document intended to describe various aspects of SNES timing. It will probably not be useful unless you already know a good bit about the SNES.

BTW, special credit to byuu for the critical observation that the SNES returns to a known timing position on reset. Thus, a deterministic ROM ( ...

65816 Reference

Internal Registers

Mnemonic Friendly Name Description
A Accumulator The accumulator. This is the math register. It stores one of two operands or the result of most arithmetic and logical operations.
X, Y Index The i ...

SPC700 Reference


System Overview


8-bit SPC700, runs at ~1Mhz ...with the effective speed being half (each instruction takes a minimum of 2 cycles)


64KB (NOT 32KB), shared with everything.


4 8-bit I/O ports to transfer data to/from the ...