store16_lane: Wasm SIMD load/store instruction

The store16_lane SIMD load/store instruction stores a specified lane of a v128 i16x8 value interpretation at a given memory address.

Try it

(module
  (import "console" "log" (func $log (param i32)))
  (memory $memory 1)
  (func $main
    i32.const 0
    v128.const i16x8 120 140 160 180 200 220 240 260
    v128.store16_lane 7

    i32.const 0
    v128.load
    i16x8.extract_lane_u 0
    call $log
  )
  (start $main)
)
WebAssembly.instantiateStreaming(fetch("{%wasm-url%}"), { console });

Syntax

;; Common usage
v128.store16_lane lane_idx

;; With optional immediate operands
v128.store16_lane mem_idx offset=int align=int lane_idx
v128.store16_lane

The v128.store16_lane instruction.

mem_idx Optional

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

offset=int Optional

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

align=int Optional

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 2. 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

Instruction Binary format Example text => binary
v128.store16_lane 0xfd 89:u32 mem_idx:u8 offset:u32 align:u32 l:laneidx v128.store16_lane 0 offset=0 align=2 7 => 0xfd 0x59 0x01 0x00 0x07

Note: While 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=2 is equivalent to 0x01 (2^1).

Specifications

This feature does not appear to be defined in any specification.

Browser compatibility

See also