NEMU(NJU Emulator) is a simple but complete full-system emulator designed for teaching purpose. Currently it supports x86, mips32, and riscv32. To build programs run above NEMU, refer to the AM project.

The main features of NEMU include

a small monitor with a simple debugger
single step
register/memory examination
expression evaluation without the support of symbols
watch point
differential testing with reference design (e.g. QEMU)
snapshot
CPU core with support of most common used instructions
x86
real mode is not supported
x87 floating point instructions are not supported
mips32
CP1 floating point instructions are not supported
riscv32
only RV32IM
memory
paging
TLB is optional (but necessary for mips32)
protection is not supported
interrupt and exception
protection is not supported
5 devices
serial, timer, keyboard, VGA, audio
most of them are simplified and unprogrammable
2 types of I/O
port-mapped I/O and memory-mapped I/O