int8

PropertyValue
Size1 byte (8 bits)
Minimum value−27 = −128
Maximum value27−1 = 127
Literal suffixi8
RepresentationTwo's complement
Hardware supportNative on all supported targets

int8 is the narrowest signed integer in Rux — a fixed-width type whose size is identical on every target platform. Like all signed types it uses two's complement: the most significant bit is the sign bit. The range is asymmetric — the minimum (−128) has no positive counterpart, since the maximum is only 127.

Literals

let a: int8 = -100;  // explicit annotation
let b = 42i8;        // type suffix

If a literal value does not fit in int8, the compiler emits an error at compile time. See Literals for decimal, hexadecimal, octal, and binary forms.

Typical Use Cases

  • Small enumeration values and byte-ranged quantities
  • Compact storage in large arrays and packed structures
  • Delta values in compressed data formats

Arithmetic

OperatorDescriptionCompound
+Addition+=
-Subtraction-=
*Multiplication*=
/Division/=
%Remainder%=
**Exponentiationn/a
let a: int8 = 10;
let b: int8 = 3;

let sum  = a + b;   // 13
let quot = a / b;   // 3   truncates toward zero
let rem  = a % b;   // 1   carries the sign of the dividend

Division and remainder truncate toward zero, so the remainder takes the sign of the dividend: -7 % 2 is -1.

Overflow. In debug builds, signed overflow raises a fatal error. In release builds it wraps modulo 28 in two's-complement fashion. Wraparound is well-defined in Rux (unlike C/C++), but relying on it is almost always a logic error.

Comparison

OperatorDescriptionResult
==Equalbool
!=Not equalbool
<Less thanbool
<=Less than or equalbool
>Greater thanbool
>=Greater than or equalbool

Both operands must have the same type. Comparing int8 with another integer type — or with an unsigned type such as uint8 — is a compile-time error; cast one operand explicitly first.

Shift and Bitwise

Right shift with >> on a signed value is arithmetic: vacated bits are filled with the sign bit, preserving the sign. To fill with zeros instead, use the logical right shift >>>, which keeps the same signed type and width.

let s: int8 = -8;  // 0b11111000
let r = s >> 2;    // 0b11111110 = -2

The bitwise operators &, |, ^, and ~ are also defined (~x equals −(x + 1)), but bitmask work usually reads more clearly on unsigned types.

Conversion

Rux performs no implicit numeric conversions — every conversion uses the as operator. Widening to a wider signed type preserves the value through sign extension; a same-width signed↔unsigned cast reinterprets the bit pattern.

let x: int8 = -1;
let wide = x as int32;   // -1    sign-extended, value preserved
let u    = x as uint8;   // 255   same width, bits reinterpreted

See Also