diff options
| -rw-r--r-- | library/core/src/primitive_docs.rs | 41 |
1 files changed, 21 insertions, 20 deletions
diff --git a/library/core/src/primitive_docs.rs b/library/core/src/primitive_docs.rs index 5d8f4366e15..a7037b2a119 100644 --- a/library/core/src/primitive_docs.rs +++ b/library/core/src/primitive_docs.rs @@ -1235,26 +1235,27 @@ mod prim_f16 {} /// operations are guaranteed to exactly preserve the bit pattern of their input except for possibly /// changing the sign bit. /// -/// The following rules apply when a NaN value is returned from an arithmetic operation: the result -/// has a non-deterministic sign. The quiet bit and payload are non-deterministically chosen from -/// the following set of options: -/// -/// - **Preferred NaN**: The quiet bit is set and the payload is all-zero. -/// - **Quieting NaN propagation**: The quiet bit is set and the payload is copied from any input -/// operand that is a NaN. If the inputs and outputs do not have the same payload size (i.e., for -/// `as` casts), then -/// - If the output is smaller than the input, low-order bits of the payload get dropped. -/// - If the output is larger than the input, the payload gets filled up with 0s in the low-order -/// bits. -/// - **Unchanged NaN propagation**: The quiet bit and payload are copied from any input operand -/// that is a NaN. If the inputs and outputs do not have the same size (i.e., for `as` casts), the -/// same rules as for "quieting NaN propagation" apply, with one caveat: if the output is smaller -/// than the input, droppig the low-order bits may result in a payload of 0; a payload of 0 is not -/// possible with a signaling NaN (the all-0 significand encodes an infinity) so unchanged NaN -/// propagation cannot occur with some inputs. -/// - **Target-specific NaN**: The quiet bit is set and the payload is picked from a target-specific -/// set of "extra" possible NaN payloads. The set can depend on the input operand values. -/// See the table below for the concrete NaNs this set contains on various targets. +/// The following rules apply when a NaN value is returned from an arithmetic operation: +/// - The result has a non-deterministic sign. +/// - The quiet bit and payload are non-deterministically chosen from +/// the following set of options: +/// +/// - **Preferred NaN**: The quiet bit is set and the payload is all-zero. +/// - **Quieting NaN propagation**: The quiet bit is set and the payload is copied from any input +/// operand that is a NaN. If the inputs and outputs do not have the same payload size (i.e., for +/// `as` casts), then +/// - If the output is smaller than the input, low-order bits of the payload get dropped. +/// - If the output is larger than the input, the payload gets filled up with 0s in the low-order +/// bits. +/// - **Unchanged NaN propagation**: The quiet bit and payload are copied from any input operand +/// that is a NaN. If the inputs and outputs do not have the same size (i.e., for `as` casts), the +/// same rules as for "quieting NaN propagation" apply, with one caveat: if the output is smaller +/// than the input, droppig the low-order bits may result in a payload of 0; a payload of 0 is not +/// possible with a signaling NaN (the all-0 significand encodes an infinity) so unchanged NaN +/// propagation cannot occur with some inputs. +/// - **Target-specific NaN**: The quiet bit is set and the payload is picked from a target-specific +/// set of "extra" possible NaN payloads. The set can depend on the input operand values. +/// See the table below for the concrete NaNs this set contains on various targets. /// /// In particular, if all input NaNs are quiet (or if there are no input NaNs), then the output NaN /// is definitely quiet. Signaling NaN outputs can only occur if they are provided as an input |