Basic Data Types

void

The void type has no associated value and is currently used only as a function return value type.

match_kind

• The match_kind type is used to declare available key matching modes. Currently, exact matching (exact) and fuzzy matching (ternary) are supported.
• match_kind is declared in the architecture file hydra_core.hdr. You cannot declare a new match_kind.

bool

Boolean value.

• true
• false

Integer (signed/unsigned)

• Fixed-width unsigned integer: bit<size>
• Fixed-width signed integer: int<size>

An integer literal can consist of the bit width and value. For example, 8w10 indicates an 8-bit unsigned integer whose value is 10.

• w: Unsigned integer
• s: Signed integer

The following are some examples of integer literals.

32w255 // 32-bit unsigned integer whose value is 255.
32w0d255 // Same as above. 0d indicates decimal (default).
32w0xFF // Same as above. 0x indicates hexadecimal.
32s0xFF // 32-bit signed integer whose value is 255.
8w0b10101010 // 8-bit unsigned integer whose value is 170. 0b indicates binary.
8w0b_1010_1010 // Same as above. The underscores are used to facilitate reading.