SIMD.%type%.bool()

Syntax

SIMD.Int8x16.bool(s0,s1,s2,s3,s4,s5,s6,s7,s8,s9,s10,s11,s12,s13,s14,s15)
SIMD.Int16x8.bool(s0,s1,s2,s3,s4,s5,s6,s7,s8)
SIMD.Int32x4.bool(s0,s1,s2,s3,s4)

Parameters

s[0-15] Optional

Boolean flag for each lane. Defaults to false.

Description

The SIMD.%type%.bool() constructor is used to create a custom selection mask. Masking (or "branching") the lanes is useful as you can't operate on a fraction of data in SIMD data types. However, with masks and the select function, you can branch and merge vectors to assemble the result vector you need.

Examples

Custom selection mask

This example uses the Int32x4.bool() function to create a custom selection mask. With this particular mask, you are able to select the first and the last lane from the first Float32x4 data type. Thus, the select function selects the first and last lane from vector a and the second and third lane from vector b (or the sum vector in the second example).

var a = SIMD.Float32x4(1, 2, 3, 4);
var b = SIMD.Float32x4(5, 6, 7, 8);

var mask = SIMD.Int32x4.bool(true, false, false, true);

SIMD.Float32x4.select(mask, a, b);
// Float32x4[1, 6, 7, 4]

var sum = SIMD.Float32x4.add(a,b);
SIMD.Float32x4.select(mask, a, sum);
// Float32x4[1, 8, 10, 4]

You can imagine the selection visually like this:

Specifications

SIMD is not yet part of an official standards document or draft. In the latest specification draft, the bool() method is replaced by SIMD Boolean type. Current implementations (e.g. Firefox Nightly) will be updated soon and this method will be removed.

Browser compatibility

See also

• SIMD
• SIMD.%type%.select()