Opcodes – The Retro CPU Reference
The definitive opcode reference for the legendary processors that launched the personal computer revolution.
Whether you're a retrocomputing enthusiast, a student of computer history, writing code for classic hardware, or just a big old nerd - the Opcodes app gives you everything you need.
Eighteen iconic processors covered: Intel 4004 · Intel 8008 · Intel 8080 · Intel 8085 · Intel 8088 · Zilog Z80 · Motorola 6800 · Intel 8085 · Motorola 6809 · MOS 6502 · Signetics 2650 · RCA 1802 - SC/MP · Motorola 68000 · Intel 8086 · WDC 65816 · Texas Instruments TMS9900 · INMOS Transputer · ARM2
For every opcode:
• Full description of what the instruction does.
• Hex, octal, and decimal values.
• Flags affected.
• Addressing modes and cycle counts.
• Assembly code examples - including loops, conditionals, and common patterns.
More than just opcodes:
• CPU history and historical context.
• IC pinout diagrams.
• Notable systems that used each chip, with memory maps.
• Chip variants and successors.
• A silly card game(!)
• Simple assembler / disassembler for many CPUs.
Built for exploration:
• Search for opcodes by name or category.
• Sort by mnemonic, opcode byte, or category.
• Filter by category, Quick Find with a colorful map.
• Undocumented instructions clearly marked and optionally displayed.
More than microprocessors:
• Information on key support chips: video, sound, memory and more.
Beautifully designed:
• Clean, readable layout optimised for quick reference.
• Multiple colour themes.
• Full "dark mode" support.
Everything is included with absolutely no in-app purchase required.
The definitive opcode reference for the legendary processors that launched the personal computer revolution.
Whether you're a retrocomputing enthusiast, a student of computer history, writing code for classic hardware, or just a big old nerd - the Opcodes app gives you everything you need.
Eighteen iconic processors covered: Intel 4004 · Intel 8008 · Intel 8080 · Intel 8085 · Intel 8088 · Zilog Z80 · Motorola 6800 · Intel 8085 · Motorola 6809 · MOS 6502 · Signetics 2650 · RCA 1802 - SC/MP · Motorola 68000 · Intel 8086 · WDC 65816 · Texas Instruments TMS9900 · INMOS Transputer · ARM2
For every opcode:
• Full description of what the instruction does.
• Hex, octal, and decimal values.
• Flags affected.
• Addressing modes and cycle counts.
• Assembly code examples - including loops, conditionals, and common patterns.
More than just opcodes:
• CPU history and historical context.
• IC pinout diagrams.
• Notable systems that used each chip, with memory maps.
• Chip variants and successors.
• A silly card game(!)
• Simple assembler / disassembler for many CPUs.
Built for exploration:
• Search for opcodes by name or category.
• Sort by mnemonic, opcode byte, or category.
• Filter by category, Quick Find with a colorful map.
• Undocumented instructions clearly marked and optionally displayed.
More than microprocessors:
• Information on key support chips: video, sound, memory and more.
Beautifully designed:
• Clean, readable layout optimised for quick reference.
• Multiple colour themes.
• Full "dark mode" support.
Everything is included with absolutely no in-app purchase required.
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