The type bit has two values, on (true, high) and off (false, low). In certain contexts (if and while statements) an expression of type bit is required.
var bit a = high
var byte x
a = x > 5
A byte is an 8-bit integer with modulo 256 semantics. Negative values are interpreted modulo 256 so (for expressions of the type byte) -1 and 255 are two notations of the same value.
var byte n = 1, m = 257
if n == m then
-- will be executed!
end if
Another type, universal, is available at compile time only. An expression which is not forced to be of a certain type is of the type universal. Such expressions can involve only constants, literals and build-in oprators and are evaluated by the compiler as signed integers of at least 32 bits.
const xtal = 10_000_000
const mips = xtal / 4