add_sat_u: Wasm SIMD arithmetic instruction
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.
Try it
(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:0to255(the full range of an unsigned 8-bit integer)i16x8.add_sat_u:0to65,535(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:i8x16i16x8
add_sat_u-
The
add_sat_uinstruction. Must always be included after thevalue_typeand a period (.).
Type
[input1, input2] -> [output]
Binary encoding
| Instruction | Binary format | Example text => binary |
|---|---|---|
i8x16.add_sat_u |
0xfd 112:u32 |
i8x16.add_sat_u => 0xfd 0x70 |
i16x8.add_sat_u |
0xfd 144:u32 |
i16x8.add_sat_u => 0xfd 0x90 0x01 |