extract_lane: Wasm SIMD extract instruction

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

Try it

(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

Specifications

• WebAssembly Core Specification

See also

• replace_lane