Symbols are evaluated to yield {section NNN} where section is one of text, data, bss, absolute, or undefined. NNN is a signed, 2’s complement 32 bit integer.
Numbers are usually integers.
A number can be a flonum or bignum. In this case, you are warned that only the low order 32 bits are used, and as pretends these 32 bits are an integer. You may write integer-manipulating instructions that act on exotic constants, compatible with other assemblers.
Sub-expressions are a left parenthesis ‘(’ followed by an integer expression, followed by a right parenthesis ‘)’; or a prefix operator followed by an argument.