xa 2.3.12 Two-pass portable cross-assembler

xa is a high-speed, two-pass portable cross-assembler. It understands mnemonics and generates code for NMOS 6502s (such as 6502A, 6504, 6507, 6510, 7501, 8500, 8501, 8502 ...), CMOS 6502s (65C02 and Rockwell R65C02) and the 65816.