Builtin Types

Builtin types are types which cannot be modeled as a UDT but are required as the most primitive form of representing a value. That’s why builtin types are also called primitive types in a lot of languages.

The table below is a complete list of all available builtin types.

Builtin Types

Name	Category	Size (in bits)	Min Value/Exponent Bits	Max Value/Significant Bits
void	Void Type	0	none	none
char	Unsigned Integer	32	\(0\)	\(4,294,967,295\)
bool	Truth Type	8	\(0\)	\(1\)
i<n>	Signed Integer	n	\(-(2^{n-1})\)	\(2^{n-1}-1\)
isize	Signed Size Type	GPR Width (w)	\(-(2^{w-1})\)	\(2^{w-1}-1\)
u<n>	Unsigned Integer	n	\(0\)	\(2^n\)
usize	Unsigned Size Type	GPR Width (w)	\(0\)	\(2^w\)
f16	IEEE-754	16	5 Bits	10 Bits
f32	IEEE-754	32	8 Bits	23 Bits
f64	IEEE-754	64	11 Bits	52 Bits
f128	IEEE-754	128	15 Bits	112 Bits

Void Type

A sizeless type that indicates a function which does not return any value. Using void as a function return type makes that function a subroutine.

Truth Type

A boolean value which can either be true (on, 1, etc.) or false (off, 0, etc.).

This type may also be used as a type for bitfields.

Signed Integer

A signed integer is an integer which may be negative or positive, but has half the numeric range of its unsigned counterpart.

If an unsigned value is assigned to a signed integer, the literal value will be converted to the numeric range of the given signed type and may under-/overflow. This means a value of -1 assigned to a u32 will result in an underflow, setting all binary digits in the value to 1.

This type may also be used as a type for bitfields.

Signed Size Type

A signed size type is guaranteed to be the size of a general-purpose register on the target architecture, and has half the numeric range of its unsigned counterpart since it can be negative.

If an unsigned value is assigned to a signed size value, the literal value will be converted to the numeric range of the given signed size type and may under-/overflow. This means a value of -1 assigned to a usize will result in an underflow, setting all binary digits in the value to 1.

This type may also be used as a type for bitfields.

Unsigned Integer

An unsigned integer is an integer which may only be positive, but has double the numeric range of its signed counterpart.

This type may also be used as a type for bitfields.

Unsigned Size Type

An unsigned size type is guaranteed to be the size of a general-purpose register on the target architecture, and has double the numeric range of its signed counterpart since it cannot be negative.

This type may also be used as a type for bitfields.

IEEE-754

A half-, single-, double- or quadruple-precision floating point number. For more information see the IEEE 754 Wikipedia page.