The add_sat_u SIMD arithmetic instruction performs a saturating addition of two unsigned v128 value interpretations — clamping the output to the range allowed by the value type. Each lane of the output value is the result of adding the corresponding lanes of the input value.

(module
  (import "console" "log" (func $log (param i32)))
  (func $main
    v128.const i16x8 4 6 16 8 23 65 82 9
    v128.const i16x8 0 25 2 30 2 34 45 80

    i16x8.add_sat_u
    i16x8.extract_lane_s 7
    call $log ;; log the result
  )
  (start $main)
)

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

Saturation means that the output values are clamped to the upper and lower values allowed by the value interpretation instead of wrapping. Allowed output values are:

• i8x16.add_sat_u: 0 to 255 (the full range of an unsigned 8-bit integer)

• i16x8.add_sat_u: 0 to 65,535 (the full range of an unsigned 16-bit integer)

Syntax

value_type.add_sat_u

• value_type

  • : The type of value the instruction is being run on. The following types support add_sat_u:

    • i8x16

    • i16x8

  add_sat_u

  • : The add_sat_u instruction. Must always be included after the value_type and a period (.).

Type

[input1, input2] -> [output]

• input1

  • : The first input value.

  input2

  • : The second input value.

  output

  • : The output value.

Binary encoding

InstructionBinary formatExample text => binaryi8x16.add_sat_u0xfd 112:u32i8x16.add_sat_u => 0xfd 0x70i16x8.add_sat_u0xfd 144:u32i16x8.add_sat_u => 0xfd 0x90 0x01

Specifications

Browser compatibility

See also

• add