extract_lane_u: Wasm SIMD extract instruction

Try it

(module
  (import "console" "log" (func $log (param i32)))
  (func $main
    ;; load a SIMD value onto the stack
    (v128.const i16x8 1 0 -2 -1 -4 -2 -2 3)

    i16x8.extract_lane_u 6 ;; Extract a scalar value from the result
    call $log ;; log the result
  )
  (start $main)
)

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

Syntax

value_type.extract_lane_u

value_type

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

i8x16
i16x8

extract_lane_u

The extract_lane_u 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

Instruction	Binary format	Example text => binary
`i8x16.extract_lane_u`	`0xfd 22:u32 l:laneidx`	`i8x16.extract_lane_u 11` => `0xfd 0x16 0x0b`
`i16x8.extract_lane_u`	`0xfd 25:u32 l:laneidx`	`i16x8.extract_lane_u 7` => `0xfd 0x19 0x07`