🏠 Atari Jaguar Developer Reference ▸ Reference ▸ Glossary
Glossary
Hardware, chip, and CD-ROM terms used across this reference. CD-specific media terms (sectors, sessions, subcodes, etc.) are defined in the CD-ROM Overview glossary.
On this page: Chips & processors · Graphics & display · Memory & system · Development hardware & tools · Addresses worth memorising
Chips & processors
| Term | Meaning |
|---|---|
| Tom | The graphics custom chip; contains the Object Processor, GPU, Blitter, memory controller, and video timing. See overview. |
| Jerry | The sound/I-O custom chip; contains the DSP, timers, serial interfaces, and joystick interface. See overview. |
| CPU / 68000 | Motorola 68000 acting as the Jaguar’s system manager — control flow, not the performance path. |
| Object Processor (OP) | Display-list engine in Tom that builds each scan line from the object list. |
| GPU | Graphics Processor — RISC co-processor in Tom, 4 KB internal RAM. See gpu. |
| DSP | Digital Sound Processor — RISC co-processor in Jerry, 8 KB internal RAM. See dsp. |
| Blitter | Block-transfer engine in Tom (move/fill, line draw, Gouraud, Z-buffer). See blitter. |
| Butch | The CD-ROM interface chip; routes CD data to Jerry’s I²S interrupt. Rev 1 vs 2 affects which CD BIOS runs. See cdrom/hardware. |
| Midsummer | Codename of a later/enhanced Jaguar chipset (see the Midsummer Tech Ref source). |
Graphics & display
| Term | Meaning |
|---|---|
| Object list | The list of objects (commands) the OP processes each scan line: bit-map (scaled/unscaled), branch, stop, and GPU-interrupt objects. |
| Object header | Per-object descriptor — 2 phrases (unscaled) or 3 phrases (scaled). |
| Line buffer | One of two 360×32-bit RAMs the OP writes a scan line into while the other is displayed. |
| Phrase | 64 bits (8 bytes) — the Jaguar’s wide-memory transfer unit. The Blitter’s phrase mode reads/writes 64 bits at a time. |
| Long / longword | 32 bits (4 bytes). CD data maintains long alignment only. |
| CRY | Cyan-Red-Intensity — a 16-bit color model that is cheap to Gouraud-shade and near-indistinguishable from 24-bit RGB. See color-cry. |
| CLUT | Color Look-Up Table at $F00400–$F007FE; palette for sub-16-bit objects. |
| Gouraud shading | Hardware smooth shading across a span; 16-bit-pixel mode only. |
| Z-buffer | Per-pixel depth test the Blitter can apply; 16-bit-pixel mode only. |
| SCRENX / SRCENX | Blitter “source enable extra (read)” — forces an extra phrase read when first-write data isn’t in the first read. See blitter. |
Memory & system
| Term | Meaning |
|---|---|
| Phrase mode | Blitter mode operating on 64-bit phrases; both address generators must be in it. |
| Scoreboarding | GPU/DSP pipeline hazard mechanism that stalls on register dependencies. See gpu. |
| I²S | Inter-IC Sound serial format used for Jerry’s audio output and the CD data path. See audio. |
| ComLynx | Asynchronous serial link (shared with the Atari Lynx) on Jerry. See serial-io. |
| NVRAM / EEPROM | 128-byte serial EEPROM in cartridges for saves/high scores; accessed via JOYSTICK bit 0. |
Development hardware & tools
| Term | Meaning |
|---|---|
| Stubulator | A retail Jaguar modified with a debugging boot ROM + stop-button cable — the dev “Jaguar Test Station.” See TechOver. |
| ROMulator / Alpine Board | Dev board emulating a ROM cartridge with battery-backed SRAM (2–4 MB) at $800000, plus host PC link. |
| Debugger stub | Debug ROM code in the dev console; reserves low memory (below $4000) and the first $2000 of ROM space. |
| SkunkBoard | A USB Flash-ROM cartridge for development on a retail console (4 MB or 8 MB). |
| CD BIOS | The required API layer for all CD access. See cdrom/bios-api. |
| Partition marker | A 64-byte block of 16 identical longwords tagging a data block on a Jaguar CD. See cdrom/data-format. |
Addresses worth memorising
| Address / range | Meaning |
|---|---|
$000000–$003FFF |
reserved low RAM in the dev environment (debugger stub); usable RAM starts at $004000 |
$000000–$1FFFFF |
2 MB main DRAM (64-bit) |
$00002C00 |
where the CD Boot ROM / CD_getoc places the TOC |
$1FFFFC |
recommended 68000 stack location |
$800000–$801FFF |
reserved cartridge/ROM security-code area |
$800000 |
cartridge / ROMulator base (32-bit) |
$802000 |
mandatory start address for cartridge programs |
$F00000–$F0FFFF |
Tom register / internal space |
$F03000–$F03FFF |
GPU internal RAM (4 KB) |
$F10000–$F1FFFF |
Jerry register / internal space |
$F14000 |
JOYSTICK register |
$F1B000–$F1CFFF |
DSP internal RAM (8 KB) |
See also
◀ Prev: RISC Instruction Set (GPU/DSP) · 🏠 Home · Next: Source Provenance ▶
Jump to: Architecture · Memory Map · Registers · Instructions · CD-ROM