NAME

	mix – MIX assembler and emulator

SYNOPSIS

	games/mix [ –g ] [ file ... ]

DESCRIPTION

Mix is an assembler and emulator for Donald Knuth's fictitious MIX architecture. The command assembles the named MIXAL files into memory and then presents a command prompt to control an emulated MIX machine. The –g option causes the emulator immediately to run a complete assembled MIX program and exits when the emulator halts. The following commands are accepted: addr[(a:b)] Print the value at addr. An optional field specification is given by (a:b). a [< file] Start the MIXAL assembler. The assembler will begin assembling at the address after the last assembled instruction. If no file is given, the assembler will accept instructions from the console. b addr Set or unset a breakpoint at addr. c     Resets the MIX machine to a fresh state by clearing all memory and registers. d addr Disassemble the instruction at addr. o addr Print the alphanumeric MIX word at addr. o(addr, d) Print d alphanumeric mix words starting at addr. r*[(a:b)] Print the value in register r* where * is one of a, x, ax, j, or 1–6. An optional field specification is given by (a:b). s     Step through one instruction of the emulated MIX machine. g     Start the emulated MIX machine at the instruction specified by the END pseudo–instruction. x     Quit the emulator/assembler. The addr field of the above instructions must be an integer between 0 and 3999 inclusive. A number–sign (#) or an asterisk (*) at the beginning of a line starts a comment which extends to the end of the line.

SOURCE

	/sys/src/games/mix

SEE ALSO

	Donald Knuth, ``The Art of Computer Programming'', Volume 1. Section 1.3 /sys/src/games/mix/examples

BUGS

	As opposed to Knuth's specification, the ALF pseudo–instruction takes as argument five MIX characters surrounded by quotation marks. Unresolved forward references are assembled to 0 instead of to a location determined by the END psuedo–instruction. The magnetic tapes and drum units are not implemented. Comments are handled as described above and not exactly as Knuth specifies.