splat: Wasm SIMD conversion instruction

The splat SIMD conversion instruction copies the same value to all lanes of a v128 value interpretation.

Try it

(module
  (import "console" "log" (func $log (param f32)))
  (func $main
    (local $s v128)
    f32.const 16.2
    f32x4.splat
    local.set $s

    local.get $s
    f32x4.extract_lane 0
    call $log ;; log the result

    local.get $s
    f32x4.extract_lane 1
    call $log ;; log the result

    local.get $s
    f32x4.extract_lane 2
    call $log ;; log the result

    local.get $s
    f32x4.extract_lane 3
    call $log ;; log the result
  )
  (start $main)
)

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

Syntax

value_type.splat

value_type

The type of value the instruction is being run on. The following v128 value interpretations support splat:

• i8x16
• i16x8
• i32x4
• i64x2
• f32x4
• f64x2

splat

The splat instruction. Must always be included after the value_type and a period (.).

Type

[input, value] -> [output]

input

The input v128 value interpretation.

value

The value you want to copy to all lanes of the v128.

output

The resulting v128 value interpretation after all lanes of the input value have been set to the value.

Binary encoding

Specifications

• WebAssembly Core Specification