The extract_lane SIMD extract instruction extracts the value contained within the specified lane of a v128 value interpretation.

(module
  (import "console" "log" (func $log (param f32)))
  (func $main
    ;; load two SIMD values onto the stack
    (v128.const f32x4 0x9 0xa 0xb 0xc)
    (v128.const f32x4 0x10 0x11 0x12 0x13)

    f32x4.add ;; add the two values
    f32x4.extract_lane 0 ;; Extract a float value from the result
    call $log ;; log the result
  )
  (start $main)
)

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

Syntax

value_type.extract_lane

• value_type

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

    • i32x4

    • i64x2

    • f32x4

    • f64x2

  extract_lane

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

Type

[input, lane] -> [output]

• input

  • : The v128 value interpretation you want to extract a lane from.

  lane

  • : The index of the lane whose value you wish to extract, for example 0.

  output

  • : The value extracted from the lane.

Binary encoding

InstructionBinary formatExample text => binaryi32x4.extract_lane0xfd 27:u32 l:lane_idxi32x4.extract_lane 3 => 0xfd 0x1b 0x03i64x2.extract_lane0xfd 29:u32 l:lane_idxi64x2.extract_lane 1 => 0xfd 0x1d 0x01f32x4.extract_lane0xfd 31:u32 l:lane_idxf32x4.extract_lane 3 => 0xfd 0x1f 0x03f64x2.extract_lane0xfd 33:u32 l:lane_idxf64x2.extract_lane 1 => 0xfd 0x21 0x01

Specifications

Browser compatibility

See also

• replace_lane