Compute the double word product of two signed 32-bit integers.
var imuldw = require( '@stdlib/number/int32/base/muldw' );Multiplies two signed 32-bit integers and returns an array of two signed 32-bit integers which represents the signed 64-bit integer product.
var v = imuldw( 1, 10 );
// returns [ 0, 10 ]
v = imuldw( 0x80000000|0, 0x40000000|0 ); // -(2^31) * 2^30 = -2305843009213694000 => 32-bit integer overflow
// returns [ -536870912, 0 ]Multiplies two signed 32-bit integers and assigns results representing the signed 64-bit integer product to a provided output array.
var out = [ 0, 0 ];
var v = imuldw.assign( 1, 10, out, 1, 0 );
// returns [ 0, 10 ]
var bool = ( v === out );
// returns true- When computing the product of 32-bit integer values in double-precision floating-point format (the default JavaScript numeric data type), computing the double word product is necessary in order to avoid exceeding the maximum safe double-precision floating-point integer value.
var lpad = require( '@stdlib/string/left-pad' );
var imuldw = require( '@stdlib/number/int32/base/muldw' );
var i;
var j;
var y;
for ( i = 0x7FFFFFF0; i < 0x7FFFFFFF; i++ ) {
for ( j = i; j < 0x7FFFFFFF; j++) {
y = imuldw( i|0, j|0 );
console.log( '%d x %d = 0x%s%s', i|0, j|0, lpad( ( y[0] >>> 0 ).toString( 16 ), 8, '0'), lpad( ( y[1] >>> 0 ).toString( 16 ), 8, '0' ) );
}
}@stdlib/number/int32/base/mul: perform C-like multiplication of two signed 32-bit integers.