the project i have in mind (project guidance board) involves firing scr's in a 3 phase macine.
looking at the opcodes of the arduino core i can see an assembler routine of a couple of hundred
lines would suffice. i have (many years past) had some experience with assembler and like
how close it brings you 'to the machine'.
can assembler routines be written for the arduino and if so how?
could such routines be embedded in 'c' code without upsetting the complier/linker/loader?
Of course, for ultimate lightness and speed, you could program the AVR chip directly and not bother with any of the Arduino stuff at all. Completely skip the C++ and all that and just replace the bootloader (or use a blank AVR chip) with your own code with an ICSP programmer.
The inline assembler totally sucks and IMO is only good for small pieces of code.
If you are determined to write in ASM I would just use AVR Studio and an ISP programmer.
Alternatively you may be able to include a .S file in the linking so you can write an assembler module without all the annoying inline crap. I know you can do that with the LPC ARM environment but haven't tried with Arduino.
A way to learn assembler is often to use the dissassembler, in the distribution of the Arduino there is one called objdump.exe, IIRC you need the -D flag.
gives you C code mixed with assembly, maybe not optimized but allways a starting point.