Yet another Javascript DCPU-16 assembler/disassembler/emulator/profiler. Code here, by @HulkHolden.
Enter/edit code below. It's assembled as you type, and errors are shown immediately below the source window (with squigglies a-la Clang :). If the source compiles ok, use step and Run to execute the code. You can use the Debug tab to see the compiled code and register state (slows things down though!). The code is profiled as it runs - hot instructions appear in the disassembly with a red background. Cycle costs should be accurate (as per the v1.1 spec).
Stuff that doesn't work yet:
macros (they should be parsed ok, but you can't invoke them)
push(i), pop(i) pseudo-ops (or macros?)
Some code I've seen on 0x10co.de does 'IFE a, b FOO a,b' all on one line, where 'FOO' is the conditially executed instruction. I don't support this yet.