vasm is a cross-assembler, its linker vlink has an AMSDOS output module -b amsdos.
vasm 1.7c (c) in 2002-2015 Volker Barthelmann vasm 8080/gbz80/z80/z180/rcmX000 cpu backend 0.2g (c) 2007,2009 Dominic Morris vasm oldstyle syntax module 0.12c (c) 2002-2015 Frank Wille vasm test output module 1.0 (c) 2002 Volker Barthelmann fatal error 16: no input file specified aborting...