serial.cc

一个mips虚拟机非常好代码,使用C++来编写的,希望大家多学学,

#include <string.h>
#include "assert.hh"
#include "checkpoint.hh"
#include "cpu.hh"
#include "error.hh"
#include "serial.hh"
#include "sulima.hh"


// The SerialType list.

BasicSerialType *BasicSerialType::first = 0;


// The Serializable object list.  In the interest of speed, this is
// kept as a circular linked-list guarded by a sintinel object.

Serializable Serializable::sentinel_object(0);


// The object ID generator.
SerialID Serializable::id_generator = 0;


// Fake "create" on objects that do not define a SimArgs constructor.
Serializable *
BasicSerialType::create(const SimArgs &args) const
{
    return 0;
}


// checkpoint() is pointless for the base object, but it has to be defined so
// that the sentinel object is not abstract.

void
Serializable::checkpoint(Checkpoint &, bool) const
{
    assert(UNREACHABLE);
}


// Serialized base constructor.

Serializable::Serializable(Checkpoint &cp)
    : id(extract<SerialID>(cp))
{
    // Make sure that any existing objects won't interfere with us.
    if (id_generator)
	throw Error("A checkpoint may be restored only onto a clean system.");
    next_object = &sentinel_object;
    prev_object = sentinel_object.prev_object;
    next_object->prev_object = prev_object;
    prev_object->next_object = next_object;
}


// Search the SerialType list for a module with Type name (name).

BasicSerialType &
find_type(const char *name)
{
    for (SerialTypeIterator i; i; ++i)
	if (!strcmp(i->name(), name))
	    return *i;
    throw Error("Unknown module type \"%#s\".", name);
}


// List all known module types for which a description string is available.

SimArg
list_known_modules(const SimArgs &args)
{
    if (args.length() == 1) {
	if (!strcmp(args[0], "available")) {
	    for (SerialTypeIterator i; i; ++i) {
		if (i->descr()[0]) {
		    sulima->msg("%-15s %s", i->name(), i->descr());
		}
	    }
	    return "";
	}
	else if (!strcmp(args[0], "installed")) {
	    for (ObjectIterator i; i; ++i) {
		Module *mod = dynamic_cast<Module *>(&*i);
		if (mod) {
		    sulima->msg("%-20s %s", mod->name(),
				dynamic_cast<CPU *>(mod) ? "(CPU)" : "");
		}
	    }
	    return "";
	}
    }
    throw Error(args.length() ? "Invalid arguments to \"sim::list\"." :
	"Missing argument to \"sim::list\".");
}


// An extractor for SerialType objects.

Checkpoint &
operator>>(Checkpoint &cp, BasicSerialType *&type)
{
    const char *name = extract_word(cp);
    try {
	type = &find_type(name);
    }
    catch (...) {
	delete name;
	throw;
    }
    delete name;
    return cp;
}


// Find an object with the given ID, 0 if none.
Serializable *
find_object(SerialID id)
{
    for (ObjectIterator i; i; ++i)
	if (i->id == id)
	    return &*i;
    return 0;
}