The promote_low_f32x4 SIMD conversion instruction converts the first two lanes of a v128 f32x4 value interpretation into an f64x2 value interpretation.

(module
  (import "console" "log" (func $log (param f64)))
  (func $main
    v128.const f32x4 0x3 0x3a 0x4b 0x5a

    f64x2.promote_low_f32x4
    f64x2.extract_lane 1
    call $log ;; log the result
  )
  (start $main)
)

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

Syntax

value_type.promote_low_f32x4

• value_type

  • : The type of value the instruction is being run on. The following v128 value interpretations support promote_low_f32x4:

    • f64x2

  promote_low_f32x4

  • : The promote_low_f32x4 instruction. Must always be included after the value_type and a period (.).

Type

[input] -> [output]

• input

  • : The input v128 f32x4 value interpretation.

  output

  • : The output v128 f64x2 value interpretation.

Binary encoding

InstructionBinary formatExample text => binaryf64x2.promote_low_f32x40xfd 95:u32f64x2.promote_low_f32x4 => 0xfd 0x5f

Specifications

Browser compatibility