The reinterpret numeric instructions are used to reinterpret the bits of a number as a different type.

(module
  (import "console" "log" (func $log (param i32)))
  (func $main
    ;; the value `10000000_00000000_00000000_00000000` in binary
    ;; maps to `-0` as a floating point and to `-2147483648` as an integer.

    f32.const -0 ;; push an f32 onto the stack

    i32.reinterpret_f32 ;; reinterpret the bytes of the f32 as i32

    call $log ;; log the result
  )
  (start $main)
)

const url = "{%wasm-url%}";
await WebAssembly.instantiateStreaming(fetch(url), { console });

Syntax

;; the value `10000000_00000000_00000000_00000000` in binary
;; maps to `-0` as a floating point and to `-2147483648` as an integer

;; push an f32 onto the stack
f32.const -0

;; reinterpret the bytes of the f32 as i32
i32.reinterpret_f32

;; the top item on the stack will now be the value -2147483648 of type i32

InstructionBinary opcodei32.reinterpret_f320xbci64.reinterpret_f640xbdf32.reinterpret_i320xbef64.reinterpret_i640xbf

Specifications

Browser compatibility