static int b_extract(LuaState L)
{
int w = 0;
b_uint r = luaL_checkunsigned(L, 1);
int f = fieldargs(L, 2, ref w);
r = (r >> f) & mask(w);
lua_pushunsigned(L, r);
return(1);
}
static int b_rot(LuaState L, int i)
{
b_uint r = luaL_checkunsigned(L, 1);
i &= (LUA_NBITS - 1); /* i = i % NBITS */
r = trim(r);
r = (r << i) | (r >> (LUA_NBITS - i));
lua_pushunsigned(L, trim(r));
return(1);
}
static b_uint andaux(LuaState L)
{
int i, n = lua_gettop(L);
b_uint r = ~(b_uint)0;
for (i = 1; i <= n; i++)
{
r &= luaL_checkunsigned(L, i);
}
return(trim(r));
}
static int b_xor(LuaState L)
{
int i, n = lua_gettop(L);
b_uint r = 0;
for (i = 1; i <= n; i++)
{
r ^= luaL_checkunsigned(L, i);
}
lua_pushunsigned(L, trim(r));
return(1);
}
static int b_or(LuaState L)
{
int i, n = lua_gettop(L);
b_uint r = 0;
for (i = 1; i <= n; i++)
{
r |= luaL_checkinteger(L, i);
}
lua_pushnumber(L, trim(r));
return(1);
}
static int b_replace(LuaState L)
{
int w = 0;
b_uint r = luaL_checkunsigned(L, 1);
b_uint v = luaL_checkunsigned(L, 2);
int f = fieldargs(L, 3, ref w);
lua_Unsigned m = mask(w);
v &= m; /* erase bits outside given width */
r = (r & ~(m << f)) | (v << f);
lua_pushunsigned(L, r);
return(1);
}
static int b_arshift(LuaState L)
{
b_uint r = luaL_checkunsigned(L, 1);
int i = luaL_checkint(L, 2);
if (i < 0 || (r & ((b_uint)1 << (LUA_NBITS - 1))) == 0)
{
return(b_shift(L, r, -i));
}
else
{ /* arithmetic shift for 'negative' number */
if (i >= LUA_NBITS)
{
r = ALLONES;
}
else
{
r = trim((r >> i) | ~(~(b_uint)0 >> i)); /* add signal bit */
}
lua_pushunsigned(L, r);
return(1);
}
}
static int b_shift(LuaState L, b_uint r, int i)
{
if (i < 0)
{ /* shift right? */
i = -i;
r = trim(r);
if (i >= LUA_NBITS) r = 0;
else r >>= i;
}
else
{ /* shift left */
if (i >= LUA_NBITS) r = 0;
else r <<= i;
r = trim(r);
}
lua_pushnumber(L, r);
return 1;
}
