RealXV6 vs Opcodes

【 Bring Lions' Commentary to Life 】 If you are studying operating systems, you know the legend: Lions' Commentary on UNIX 6th Edition. It is the "Red Book" that taught a generation of hackers how an OS kernel truly works. Now, you can bring that bible to life on your iOS device. 【 From Reading to Experiencing 】 The biggest challenge in understanding Unix v6 is that reading code is static, but an operating system is dynamic. We have solved this problem. We ported the classic Unix v6 to the Intel 8086 architecture (Real Mode) and built a powerful virtual machine around it. This isn't just an emulator—it is an interactive learning environment designed to help you verify the logic described in the book. 【 Key Features 】 The Ultimate Study Companion: Designed specifically to accompany your reading of the Lions' source code. Don't just imagine how the code runs—watch it happen. Source-Level Debugging: Say goodbye to raw assembly guesswork. Set breakpoints directly in the C source code to pause execution at critical moments. Precise Execution Control: Master the kernel's logic with full stepping capabilities. Step In: Dive into function calls to see how the kernel handles sub-routines. Step Over: Execute lines quickly to grasp the high-level flow. Step Out: Quickly return to the caller function to understand the call stack hierarchy. Deep Dive into the Kernel: Struggle to understand the complex flow of context switching or interrupts? Place a breakpoint on swtch() or trap() and trace the execution path line-by-line. Simplified 8086 Architecture: By running on 8086 Real Mode, the underlying hardware logic is easier to understand than the original PDP-11. Portable Lab: No complex setups, no QEMU configuration. Your pocket OS laboratory is ready whenever you are. 【 Why This App? 】 Don't just read the history of computing—trace it. Whether you are a CS student grappling with OS concepts or a veteran developer revisiting the classics, this app bridges the gap between theory and practice by letting you walk through the code live.

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 CPU, with memory maps and other background information. • 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. Cool design:  • Clean, readable layout optimised for quick reference. • Multiple colour themes. • Full "dark mode" support. Everything is included with absolutely no in-app purchase required. Recent additions: • Quiz game - test your CPU knowledge! • Share CPU cards - beautiful shareable images showing specs and history for any processor • External references - curated links to community resources for all 18 CPUs • "Opcodes display first" setting - choose whether selecting a CPU shows opcodes or info first • Chip-maker colour themes - Zilog, MOS Tech, and Motorola replace the old themes • Enhanced 6502 docs - JMP page boundary bug, BRK behaviour, and Read-Modify-Write quirks • Fixed Scratchpad hang when switching tabs