 a keypress?
	this.waitReg = -1;    // destination register of an awaited key
	this.halted = true;
	this.breakpoint = false;
	this.metadata = {};
	this.tickCounter = 0;
	this.linted = false;

	// external interface stubs
	this.exitVector  = function() {}                                                           // fired by 'exit'
	this.importFlags = function() { return [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]; } // load persistent flags
	this.exportFlags = function(flags) {}                         