1 unstable release
0.1.0 | Apr 6, 2023 |
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#1587 in Procedural macros
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3KB
minus-one
let max_byte: u8 = minus_one!(256);
assert_eq!(max_byte, 255);
let min_byte: u8 = minus_one!(1);
assert_eq!(min_byte, 0);
Often in firmware-land, you are using a register where a register value of 0 corresponds to a value of 1. This is a common pattern in hardware. However, this can be a headache when you are trying to write a value to the register, and you have to remember to subtract 1 from the value you want to write. In addition, sometimes it is not even possible to subtract 1 because the value you want to write is the maximum value.
Suppose you have a u8
and you want to write something which represents scalar 256. You cannot subtract 1 from 256
because 255 is the maximum value of an u8
.
The minus_one!
macro allows you to write minus_one!(256)
and get 255
back, and likewise minus_one!(1)
will
return 0
.
Dependencies
~225–670KB
~16K SLoC