The store64_lane SIMD load/store instruction stores a specified lane of a v128 i64x2 value interpretation at a given memory address.

(module
  (import "console" "log" (func $log (param i64)))
  (memory $memory 1)
  (func $main
    i32.const 0
    v128.const i64x2 8000001 16000001
    v128.store64_lane 1

    i32.const 0
    v128.load
    i64x2.extract_lane 0
    call $log
  )
  (start $main)
)

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

Syntax

;; Common usage
v128.store64_lane lane_idx

;; With optional immediate operands
v128.store64_lane mem_idx offset=int align=int lane_idx

• v128.store64_lane

  • : The v128.store64_lane instruction.

  mem_idx

  • : An integer representing the memory index, in cases where the module uses multiple memories. The default is 0.

  offset=int

  • : An integer representing a constant number of bytes to add to the address before storing. The default is 0.

  align=int

  • : An integer representing a hint to the Wasm engine about what alignment to expect for the final address. The minimum value is 1 and the default and maximum value is 8. An align value has to be a power of 2.

  lane_idx

  • : The index of the lane whose value you want to store.

Type

[memory_address, input] -> []

• memory_address

  • : An integer representing the memory address to store the input at.

  input

  • : The v128 type from which to extract a lane value to store.

Binary encoding

InstructionBinary formatExample text => binaryv128.store64_lane0xfd 91:u32 mem_idx:u8 offset:u32 align:u32 l:laneidxv128.store64_lane 0 offset=0 align=8 1 => 0xfd 0x5b 0x03 0x00 0x01While Wasm text format specifies the literal align value, the binary equivalent represents the exponent of the formula 2^x used to calculate the alignment. So for example, align=1 is equivalent to 0x00 (2^0), while align=8 is equivalent to 0x03 (2^3).

Specifications

Browser compatibility