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Javascript XOR Odditites

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Feb 04.2007

I have run into a snag with the JavaScript ^ operator for a calculation that I need to do in parallel in Delphi and in JS. Here is an example. Take two numbers

0xD9 11011001

0x9E3779B9 10011110001101110111100110111001

Delphi gives 9E377960

10011110001101110111100101100000 – the result I expect.

Javascript gives

-1640531616 = 1111111111111111111111111111111110011110001101110111100101100000

Could anyone shed some light on this mystery and suggest a way to get both Delphi and JS to behave in the same way? I would be most obliged for any help.

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JavaScript

2 Comments(s) ↴

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@Orc_ScorcherFeb 04.2007 — JavaScript's bitwise operators use signed 32 bit arithmetic. If you need an unsigned 32 bit XOR you could use the >>> operator:function U32BitXOR(a, b) {
return ((a >>> 1) ^ (b >>> 1)) * 2 + (a % 2 ^ b % 2)
}
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@FredAtauthorFeb 05.2007 — JavaScript's bitwise operators use signed 32 bit arithmetic. If you need an unsigned 32 bit XOR you could use the >>> operator:function U32BitXOR(a, b) {
return ((a >>> 1) ^ (b >>> 1)) * 2 + (a % 2 ^ b % 2)
}
[/QUOTE]

Thanks. In the mean time I had figured out this

JS_XOR(a,b){return (a|b) & ~(a&b)}
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