Torque is a meta-assembler: instead of having an instruction set built into the assembler, you use macros to build up a small language that decribes an instruction set and then you use that to write your program. It's designed to work for any microcontroller/processor architecture, you build from the bit level upwards so there aren't any assumptions around word widths, instruction formats, or endianness.

I created Torque initially to write programs for a PIC microcontroller, after running into difficulties with the official assembler. I've also used it to write programs for the Z80 processor inside an old TRS-80 computer.

Let me know if you try it out or have any questions!