extract_lane: Wasm SIMD extract instruction

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

Instruction	Binary format	Example text => binary
`i32x4.extract_lane`	`0xfd 27:u32 l:laneidx`	`i32x4.extract_lane 3` => `0xfd 0x1b 0x03`
`i64x2.extract_lane`	`0xfd 29:u32 l:laneidx`	`i64x2.extract_lane 1` => `0xfd 0x1d 0x01`
`f32x4.extract_lane`	`0xfd 31:u32 l:laneidx`	`f32x4.extract_lane 3` => `0xfd 0x1f 0x03`
`f64x2.extract_lane`	`0xfd 33:u32 l:laneidx`	`f64x2.extract_lane 1` => `0xfd 0x21 0x01`