splat: Wasm SIMD conversion instruction

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

Instruction	Binary format	Example text => binary
`i8x16.splat`	`0xfd 15:u32`	`i8x16.splat` => `0xfd 0x0f`
`i16x8.splat`	`0xfd 16:u32`	`i16x8.splat` => `0xfd 0x10`
`i32x4.splat`	`0xfd 17:u32`	`i32x4.splat` => `0xfd 0x11`
`i64x2.splat`	`0xfd 18:u32`	`i64x2.splat` => `0xfd 0x12`
`f32x4.splat`	`0xfd 19:u32`	`f32x4.splat` => `0xfd 0x13`
`f64x2.splat`	`0xfd 20:u32`	`f64x2.splat` => `0xfd 0x14`