abs: Wasm text instruction - Content

The abs instructions, short for absolute, are used to get the absolute value of a number. That is, it returns x if x is positive, and the negation of x if x is negative.

wat

(module
  (import "console" "log" (func $log (param f32)))
  (func $main

    f32.const -10 ;; load a number onto the stack
    f32.abs ;; calculate the absolute value
    call $log ;; log the result

  )
  (start $main)
)

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

Syntax

wat

;; load a number onto the stack
f32.const -2

;; absolute
f32.abs

;; the top item on the stack will now be 2

Instruction	Binary opcode
`f32.abs`	`0x8b`
`f64.abs`	`0x99`