Nullpo_head is an undergraduate student at Tokyo University in Japan.
He is a lover of caffeine and programming.


  • Ruby
  • PHP
  • JavaScript
  • HTML & CSS
  • C
  • MIPS R4k Assembly
  • x86 Assembly (as much as necessary for OS developing)
  • VHDL (cannot write so well, but can create a simple subset CPU of MIPS)

Interests & hobbies

  • Web developing
  • OS developing
  • Computer Security

Works You May Find Interesting

A tool to deceive a classroom management software by API hooking

In my technology class at junior high, teachers monitored our PC screens with a classroom management software. I created a small tool that hooks some Win32 APIs related to capturing screen. This tool made the monitoring software capture a dummy screen, and I could surf the web safely.

A programming language running on cell phones

My dorm at boarding school did not allow us to bring computers. I searched for a programming application for cell phones, which we could bring. I found an app soon, but it lacks of floating point support and has some fatal bugs. So, I downloaded the source code, fixed the problems and improved many features.
An JS port by a user is available at here. This is exactly not an port of my version, but has all features of it including undocumented ones.


I created a subset CPU of MIPS and a CPU which runs Brainfuck programs both on FPGA. The former is a result of the CPU experiment at my university. (CPU experiment is an experiment where each student group create a CPU, compiler, assembler, and simulator by themselves.) My CPU is tiny and simple but powerful enough to run a ray-tracing app.

Porting Xv6

I ported Xv6, a simple UNIX like operating system, to MIPS and our own architecture. The repository of the MIPS port is at my Github. The port to our CPU is at our group’s repository (hosted by Wasabiz.) Our architecture, GAIA, is a new CPU from scratch. It has virtual memory and interruption. See the repositroy for more detail.
I ported our xv6 to JavaScript, too. You can see how it runs here

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