![]() But given that that to-do list is getting shorter, some day I will get around to it. The only reason that I haven't done this yet is that it would be a lot of work, and given how minor an issue this is, it has never made it to the top of my to-do list yet. The DM42 runs Free42, based on a decimal floating-point maths library and IEEE 754-2008 quadruple precision decimal floating-point, encoding numbers in 16 bytes and giving 34 decimal places of precision with exponents ranging from -6143 to +6144. Given that the limitations that existed back then are no longer an issue, I could fix this, and I would like to, since the current behavior can be confusing, and it would be better to have byte counts that ALWAYS match those in program listings, even when they contain numbers that aren't minimal-length, like 1000 instead of 1E3. Storing numbers in floating-point format AND as a series of digits would have taken up more memory, which was also at a premium in PalmOS. Storing numbers as a sequence of digits would have meant performing a decimal-to-binary conversion each time a number line was executed, and those conversions are computationally expensive. The DM42 runs Free42, based on a decimal floating-point maths library and IEEE 754-2008 quadruple precision decimal floating-point, encoding numbers in 16 bytes and giving 34 decimal places of precision with exponents ranging from -6143 to +6144. Speed may not seem like an issue with Free42 today, but one of the platforms I targeted originally was PalmOS 3, which ran on 0 CPUs, and on that platform, I was barely able to match the speed of the original calculator, so I optimized for speed wherever I could. Some background: Free42 stores numbers in programs in floating-point format, because storing them as a sequence of digits, like the real HP-42S does, would have been too slow. I am mentioning this here because even though it may appear that Free42 does something differently than the HP-42S, this is a difference you should ignore. (When scientific and fixed-point representations are the same length, it chooses the latter, so 100 is displayed as 100, not as 1E2.)Īgain, none of this has any effect on how Free42 performs calculations. ![]() Free42s is an excellent free software tool for any hobbyist, whether it is creating a. ![]() When it displays a program line containing a number, it formats the number in whichever way would be the most compact on the HP-42S, so, if you enter 1000, it is displayed as 1E3, but if you enter 10, it is displayed as 10. Download Free42 HP-42S Calculator Simulator 3.0.13 for Windows free. If you want to enter the number 1000 in a program, you can enter 1000, or 1E3 the latter saves one byte, but apart from that, there is no difference.įree42, on the other hand, stores numbers in programs in floating-point format, which means that the distinction between 1000 and 1E3 is not preserved. In programs, the HP-42S stores numbers basically as you enter them. This is not actually a difference between Free42 and the HP-42S that causes HP-42S programs to fail in Free42, but it is something that can cause confusion. Quote: In programs, numbers are normalized
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