Update Zanshin_BME680.cpp #32
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readout sensor registers : use bit shift instead of * / temp sensor compensation changed shift's so that 32-bit variables can be used --> less use off 64-bit
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The c++ compiler automatically optimized these integer divisions to shift operations, so changing "x / 16" to "x >> 4" produces the same runtime code. I haven't checked to see if all values remain in range for the variables you changed from 64 to 32 bit; but they are temporary variables inside of functions so the space lost/gained is only temporary during the execution of the routines so I am not certain that the gains are worth it. |
Those changes where for clarity, when bitshifting it's clearer to use the bit shift operators.
There won't be a space advantage, but 64-bit operations are normaly a lot more time consuming that 32-bit operations. |
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I see your point about bit-shifting rather than multiplying and dividing. I'll change the corresponding locations directly in version 10 under development. But I still see some multiplying that might exceed the 32-bit values, so I'll take a look at that separately. |
I've checked with either the Bosch library, that only uses 64-bit for some measurements and 32-bit for others. The changes are to the temp calculation, that could have needed 64-bit at the start with 1 or 2 bits. I moved a >>4 to the first calculation, which would be enough. |
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I've added issue #34 with 2 additions that cover what changes you made, plus integrated the changes in computation to the source code; there would have been too many many changes to this pull request |
* Updated to new version * Updated to new version * Issue #31 addressed for incorrect humidity computation * Issue #32 Changed multiplication and division by powers of 2 to bit-shift operations for clarity * Issue #33 Also corrected travis-ci links * Issue #33 Corrected "const" definition * Issues #33 and #34 * Issue #34 Corrections to formatting * Issue #34 changes Co-authored-by: Arnd <Arnd_Github@SV-Zanshin.Com>
readout sensor registers : use bit shift instead of * /
temp sensor compensation changed shift's so that 32-bit variables can be used --> less use off 64-bit
results are the same