assembly

Files about assembly-language programming and reading low-level code.

• Game Annotation Series — documenting classic game source at the system level
• TIA Reference — chip-level facts needed to read 2600 source
• PPU Reference — chip-level facts needed to read NES source
• APU Reference — NES audio chip reference
• Mappers Reference — NES cartridge logic from NROM through MMC5
• Breaking Down an SNES Cart — 65C816 vs 6502; why a width-aware disassembler is needed
• SNES teardown — snes-decompiler — the target-agnostic SNES teardown substrate
• Battlezone (1980) — 3D Without a Multiply Instruction — reading Atari’s 12 KB of 6502 from McFadden’s commented disassembly: the memory-mapped math-box API, the vertex inner loop, quarter-wave sine and octant-folded arctan, RTS-dispatch sign fixup
• Arithmetic Scarcity and the 3D Problem — why 8086 inner loops avoided MUL too (118-133 clocks, microcoded not silicon); the four strategies for real-time 3D when arithmetic is the scarce resource
• Stellar 7 (1983) — The Same Game Without the Coprocessor — unrolled shift-add multiply (7 stages, no loop), a 4-path specialized divide with the fixed-point pre-shift folded into the signature, and a vertex loop that services bit-banged audio four times per vertex
• Arithmetic as a Purchase — Sixty Years of Paying for Multiply — the request protocol that never changed: write operands to a port, let the last write trigger, wait a known cycle bound, read the result — the 1401’s option gate, Battlezone’s $1860, the SNES’s $4202, a GPU command buffer
• KOEI tools — the shared engine toolchain — Tools node, not a title index. One studio, one bytecode-VM engine lineage, two consoles.
• LADS — byte-exact reconstruction — A reconstruction of LADS, the memory-resident 6502 assembler from Richard Mansfield’s
• Lowering Atlas — Sibling tooling to the NA1 decompiler, in the same repo: compile known C control-flow
• NA1 — Nobunaga’s Ambition (NES) — The bytecode-VM decompiler that outgrew annotation and became the series’ crucible.
• NES / Famicom — system node — The 6502 + PPU substrate and every title decompiled on it.
• The comparison studies — paired deep-reads — The four titles the series started as, organized in paired comparisons.