The load8_lane SIMD load/store instruction loads a single value from a given memory address into the specified lane of a v128 type i8x16 value interpretation.

(module
  (import "console" "log" (func $log (param i32)))
  (memory $memory 1)
  (data (i32.const 0) "\01\02\03\04\05\06\07\08\09\0a\0b\0c\0d\0e\0f\00\01\02\03")
  (func $main
    i32.const 0
    v128.const i8x16 10 4 6 5 8 7 11 3 8 12 9 7 2 31 9 1
    v128.load8_lane 9
    i8x16.extract_lane_s 9
    call $log
  )
  (start $main)
)

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

Syntax

;; Common usage
v128.load8_lane lane_value

;; With optional immediate operands
v128.load8_lane mem_idx offset=int align=int lane_value

• v128.load8_lane

  • : The v128.load8_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 memory address before loading. 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, default, and maximum value is 1.

  lane_value

  • : The lane to load a value into.

Type

[memory_address, input] -> [output]

• memory_address

  • : An integer representing the memory address to load from.

  input

  • : The input v128 type i8x16 value interpretation.

  output

  • : The output v128 type i8x16 value interpretation.

Binary encoding

InstructionBinary formatExample text => binaryv128.load8_lane0xFD 84:u32 mem_idx:u8 offset:u32 align:u32 lane_idx:u8v128.load8_lane 0 offset=0 align=1 9 => 0xfd 0x54 0x00 0x00 0x09While 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 align=1 is equivalent to 0x00 (2^0).

Specifications

Browser compatibility