Re:The Byte Order Fiasco
by dahart on Saturday May 08, 2021 @02:16PM
(#27089486)
I always think about values in big endian, largest digit first. Scientific notation, for example, since often we only care about the first few digits.
I sometimes think about arithmetic in little endian, since addition always starts with the least significant digit, due to the right-to-left dependency of carrying.
Except lately I’ve been doing large additions big-endian style left-to-right, allowing intermediate “digits” with a value greater than 9, and doing the carry pass separately after the digit addition pass. It feels easier to me to think about addition this way, even though it’s a less efficient notation.
Long division and modulus are also big-endian operations. My favorite CS trick was learning how you can compute any arbitrarily sized number mod 7 in your head as fast as people are reading the digits of the number, from left to right. If you did it little-endian you’d have to remember the entire number, but in big endian you can forget each digit as soon as you use it.
I sometimes think about arithmetic in little endian, since addition always starts with the least significant digit, due to the right-to-left dependency of carrying.
Except lately I’ve been doing large additions big-endian style left-to-right, allowing intermediate “digits” with a value greater than 9, and doing the carry pass separately after the digit addition pass. It feels easier to me to think about addition this way, even though it’s a less efficient notation.
Long division and modulus are also big-endian operations. My favorite CS trick was learning how you can compute any arbitrarily sized number mod 7 in your head as fast as people are reading the digits of the number, from left to right. If you did it little-endian you’d have to remember the entire number, but in big endian you can forget each digit as soon as you use it.