Negate

The neg instructions, short for negate, are used to negate a number. That is, turn a positive number into a negative number and a negative number into a positive number.

Try it

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

    f32.const 10 ;; load a number onto the stack
    f32.neg ;; negate the values
    call $log ;; log the result

  )
  (start $main)
)

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

Syntax

wasm

;; load a number onto the stack
f32.const 2.7

;; negate
f32.neg

;; the top item on the stack will now be -2.7

Instruction	Binary opcode
`f32.neg`	`0x8c`
`f64.neg`	`0x9a`