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Document masking of shift values #26

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Oct 20, 2020
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Document masking of shift values #26

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bed5c5b
Document masking of shift values
dcodeIO Oct 20, 2020
d9a4340
fix indentation
dcodeIO Oct 20, 2020
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9 changes: 9 additions & 0 deletions src/types.md
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Expand Up @@ -84,6 +84,15 @@ The result of a bit shift \(`<<`, `>>`\) is the left type, with the right type i

The result of an unsigned right shift \(`>>>`\) is the left type \(signedness is retained\), with the right type implicitly converted to the left type, but always performing a logical shift.

Note that only the `log2(sizeof<T>())` least signficant bits of the shift affect the result:

| Type | Significant bits | Example
| :-------- | :--------------: | :------------------------
| i8 / u8 | 3 | `x & y` ≡ `x & (y & 7)`
| i16 / u16 | 4 | `x & y` ≡ `x & (y & 15)`
| i32 / u32 | 5 | `x & y` ≡ `x & (y & 31)`
| i64 / u64 | 6 | `x & y` ≡ `x & (y & 63)`

If the left type is a float, an error is emitted.

## Macro types
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