load32_zero: Wasm SIMD load instruction
The load32_zero SIMD load instruction loads a single value from a given memory address into the first lane of a v128 type i32x4 value interpretation, and initializes the other lanes to 0.
Try it
(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 1
v128.load32_zero
i32x4.extract_lane 0
call $log
)
(start $main)
)
WebAssembly.instantiateStreaming(fetch("{%wasm-url%}"), { console });
Syntax
;; Common usage v128.load32_zero ;; With optional immediates v128.load32_zero memidx offset=int align=int
v128.load32_zero-
The
v128.load32_zeroinstruction. memidxOptional-
An integer representing the memory index, in cases where the module uses multiple memories. The default is
0. offset=intOptional-
An integer representing a constant number of bytes to add to the memory address before loading. The default is
0. align=intOptional-
An integer representing a hint to the Wasm engine about what alignment to expect for the final address. The minimum value is
1and the default and maximum value is4. Analignvalue has to be a power of2.
Type
[memory_address] -> [output]
memory_address-
An integer representing the memory address to load from.
output-
The output
v128typei32x4value interpretation.
Binary encoding
| Instruction | Binary format | Example text => binary |
|---|---|---|
v128.load32_zero |
0xFD 92:u32 memidx:u8 offset:u32 align:u32 |
v128.load32_zero 0 offset=0 align=4 => 0xfd 0x5c 0x02 0x00 |
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=1 is equivalent to 0x00 (2^0), while align=4 is equivalent to 0x02 (2^2).