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Bryan Ischo
MAME Fan
Reged: 03/28/10
Posts: 358
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Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits?
03/23/12 12:08 AM


Something I've always been curious about. MAME defines the range of input values for axes such as analog joystick axes, or deltas such as mouse motion, as -65536 to +65536.

This is 17 bits in each direction. Why not a more logical -65535 to +65535? That is 16 bits in each direction.

From my reading of the code, the entire acceptable range of input values is inclusive of these 17 bit ranges. It would make more sense if the ranges are -65536 to +65536 *non-inclusive*, but the code and the comments don't read that way.

Why are these ranges 17 bits?







Entire thread
Subject Posted by Posted on
* Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? Bryan Ischo 03/23/12 12:08 AM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? LazyCat  04/26/12 01:41 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? Derrick Renaud  04/26/12 04:06 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? LazyCat  04/26/12 07:13 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? Derrick Renaud  04/26/12 11:55 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? LazyCat  04/27/12 06:02 AM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? Derrick Renaud  04/27/12 04:34 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? LazyCat  04/29/12 12:51 AM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? LazyCat  04/28/12 06:18 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? Bryan Ischo  05/08/12 06:24 AM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? LazyCat  05/08/12 03:34 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? B2K24  04/06/12 10:11 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? mogli  04/01/12 04:55 AM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? R. Belmont  04/06/12 04:29 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? LazyCat  04/26/12 03:21 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? krick  04/27/12 05:23 AM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? Derrick Renaud  04/24/12 08:06 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? Ramirez  04/24/12 11:22 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? Sune  04/08/12 07:07 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? R. Belmont  04/09/12 04:38 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? Sune  05/08/12 11:11 PM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? R. Belmont  05/10/12 12:21 AM
. * Re: Why are MAME INPUT_ABSOLUTE_{MIN/MAX} 17 bits? mesk  04/06/12 09:58 PM

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