gettotalbytes
res = cast_int(gettotalbytes(g) >> 10);
res = cast_int(gettotalbytes(g) & 0x3ff);
g->GCestimate = gettotalbytes(g); /* update control */
if (gettotalbytes(g) > (estimate / 100) * g->gcmajorinc)
setpause(g, gettotalbytes(g));
setpause(g, gettotalbytes(g));
debt = -cast(l_mem, threshold - gettotalbytes(g));
g->GCestimate = gettotalbytes(g);
lua_assert(gettotalbytes(g) == sizeof(LG));