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10E500?
12-12-2014, 08:58 AM
Post: #9
RE: 10E500?
BCD floats are much better than binary floats at avoiding rounding errors, the likes of e.g. 24 being printed as 23.999999999999 or so. The major FPU-less CPUs from the 80s, maybe from even earlier, have support for BCD arithmetic. Binary floats are faster, however.

Advanced Mathematics Software in the TI-68k series uses a custom 10-byte format for floating-point values:
* 1 bit for sign;
* 1 bit for exponent sign;
* 14 bits (binary) for exponent;
* 64 bits (BCD) for mantissa.
In principe, this allows usage of 16 digits and exponents up to -16384/+16383. However, only some low-level BCD arithmetics functions support that extended range; many higher-level functions use overflow to infinity for exponents outside the -999/+999 range, and round to 14 or 12 digits.
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Messages In This Thread
10E500? - mpowell@rogershsa.com - 12-08-2014, 12:30 AM
RE: 10E500? - Snorre - 12-08-2014, 08:28 AM
RE: 10E500? - mpowell@rogershsa.com - 12-09-2014, 02:39 AM
RE: 10E500? - Gerald H - 12-09-2014, 12:52 PM
RE: 10E500? - mpowell@rogershsa.com - 12-09-2014, 08:21 PM
RE: 10E500? - Snorre - 12-10-2014, 05:35 PM
RE: 10E500? - mpowell@rogershsa.com - 12-11-2014, 06:55 AM
RE: 10E500? - cyrille de brébisson - 12-12-2014, 07:07 AM
RE: 10E500? - lenborje - 01-27-2015, 04:00 PM
RE: 10E500? - debrouxl - 12-12-2014 08:58 AM
RE: 10E500? - cyrille de brébisson - 01-28-2015, 10:06 AM
RE: 10E500? - Paul Dale - 01-28-2015, 10:38 AM



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