load64_zero: Wasm SIMD load instruction

The load64_zero SIMD load instruction loads a single value from a given heap address into the first lane of a v128 i64x2 value interpretation, and initializes the other lane to 0.

Try it

(module
  (import "console" "log" (func $log (param i64)))
  (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 1
    v128.load64_zero
    i64x2.extract_lane 0
    call $log
  )
  (start $main)
)
WebAssembly.instantiateStreaming(fetch("{%wasm-url%}"), { console });

Syntax

v128.load64_zero
load64_zero

The load64_zero instruction. Must always be included after v128..

Type

[memory_address] -> [output]
memory_address

An integer representing the memory address to load from.

output

The output v128 i64x2 value interpretation.

Binary encoding

Instruction Binary equivalent Example text => binary
v128.load64_zero 0xFD 93:u32 align:u32 offset:u32 v128.load64_zero 0 => 0xfd 0x5d 0x00 0x00

Specifications

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

Browser compatibility

See also