as supports both DEC syntax and BSD syntax. The only difference is that in DEC syntax, a # character is used to denote an immediate constants, while in BSD syntax the character for this purpose is $.
eneral-purpose registers are named r0 through r7. Mnemonic alternatives for r6 and r7 are sp and pc, respectively.
Floating-point registers are named ac0 through ac3, or alternatively fr0 through fr3.
Comments are started with a # or a / character, and extend to the end of the line. (FIXME: clash with immediates?)