The store SIMD load/store instruction stores all lanes of a v128 value interpretation at a given memory address.

(module
  (import "console" "log" (func $log (param i32)))
  (memory $memory 1)
  (func $main
    i32.const 0
    v128.const i16x8 20 30 40 50 60 70 80 90
    v128.store

    i32.const 0
    v128.load
    i16x8.extract_lane_s 7
    call $log
  )
  (start $main)
)

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

Syntax

;; Common usage
v128.store

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

• v128.store

  • : The v128.store 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 value 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 16. An align value has to be a power of 2.

Type

[memory_address, input] -> []

• memory_address

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

  input

  • : The v128 type to store.

Binary encoding

InstructionBinary formatExample text => binaryv128.store0xfd 11:u32 mem_idx:u8 offset:u32 align:u32v128.store 0 offset=0 align=16 => 0xfd 0x0b 0x04 0x00While 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=16 is equivalent to 0x04 (2^4).

Specifications

Browser compatibility