On several occasions I'm mentioned using "invert, and multiply" to speed up the MC-10 interpreter.
Instead of dividing by a constant, the updated ROM now multiplies by 1/constant.
When combined with the fast hardware multiply function, it results in significantly faster functions, including SIN, and COS.
For example, if a formula calls for dividing a number by the constant PI (3.14...), you recalculate the constant as 1/PI, and then multiply by it. This also works in your BASIC code, if you have to do a lot of division by a constant, you can speed up the program by multiplying with 1/constant, and that can be calculated at the top of your program.
Anyway, the reason for bringing it up again, is because I ran across this article that explains the concept, and why it works.
https://www.quickanddirtytips.com/education/math/how-to-divide-fractions-using-invert-and-multiply
Instead of dividing by a constant, the updated ROM now multiplies by 1/constant.
When combined with the fast hardware multiply function, it results in significantly faster functions, including SIN, and COS.
For example, if a formula calls for dividing a number by the constant PI (3.14...), you recalculate the constant as 1/PI, and then multiply by it. This also works in your BASIC code, if you have to do a lot of division by a constant, you can speed up the program by multiplying with 1/constant, and that can be calculated at the top of your program.
Anyway, the reason for bringing it up again, is because I ran across this article that explains the concept, and why it works.
https://www.quickanddirtytips.com/education/math/how-to-divide-fractions-using-invert-and-multiply
I forget to mention that 1/number is called the reciprocal
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