http://adventofcode.com/day/23

little_asm.groovy

def regs = [a:0, b:0]

def instr = [
	hlf: { params -> 
		def r = params.r/2
		def output 
		if(r.remainder(1) == 0) {
			output = [reg_val:r, jump_to: params.i+=1]	
		} else {
			output = [reg_val:params.r, jump_to: params.i+=1]
		}
		return output
	},
	tpl: { params -> 
		return [reg_val:params.r*=3, jump_to: params.i+=1]
	},
	inc: { params ->
		return [reg_val:params.r+=1, jump_to: params.i+=1]
	},
	jmp: { params ->
		def offset = params.r.toInteger()
		return [jump_to: params.i+offset]
	},
	jie: { params  ->
		def offset = params.i+1
		if(params.r.toInteger()%2 == 0) {
			offset = params.i + params.o.toInteger()
		}
		return [reg_val:params.r, jump_to: offset]
	},
	jio: { params ->
		def offset = params.i+1
		if(params.r.toInteger() == 1) {
			offset = params.i + params.o.toInteger()
		}
		return [reg_val:params.r, jump_to: offset]	
	}
]

def program = new File(args[0]).readLines()
def count = 0
for(i = 0; i < program.size();) {
	def (input_1, input_2, input_3) = program[i].tokenize(" ;,")
	def rgt = regs[input_2]!= null? regs[input_2]: input_2	 
	def r = instr[input_1]([r:rgt, i:i, o:input_3])
	i = r.jump_to
	if(regs[input_2] != null) {
		regs[input_2] = r.reg_val	
	}	
	println "${count++}) [${input_1}, ${input_2}] -> ${regs[input_2]}"
}