Semiconductor & Computer Engineering
From WikiChip
Difference between revisions of "boolean algebra/choose function"
(Created page with "{| class="wikitable" style="float: right;" ! colspan="3" | Inputs !! Outputs |- ! X !! Y !! Z !! Q |- | 0 || X || 0 || 0 |- | 0 || X || 1 || 1 |-...") |
m |
||
| (3 intermediate revisions by one other user not shown) | |||
| Line 1: | Line 1: | ||
| − | {| class="wikitable" style="float: right;" | + | {{ba title|Choose Function (Ch)}}{| class="wikitable" style="float: right;" |
! colspan="3" | Inputs !! Outputs | ! colspan="3" | Inputs !! Outputs | ||
|- | |- | ||
| Line 12: | Line 12: | ||
| 1 || 1 || [[don't care|X]] || 1 | | 1 || 1 || [[don't care|X]] || 1 | ||
|} | |} | ||
| − | '''Choose function''' (or '''Ch Function''') is a [[Boolean function]] that represents a [[multiplexer|2:1 MUX]]. The choose function is frequently found in various [[cryptographic hash function]]s. | + | '''Choose function''' (or '''Ch Function''') (sometimes '''if-then-else''' or '''ITE''') is a [[Boolean function]] that represents a [[multiplexer|2:1 MUX]]. The choose function is frequently found in various [[cryptographic hash function]]s. |
:<math> | :<math> | ||
| − | + | \text{Ch}(x,y,z) = | |
\begin{cases} | \begin{cases} | ||
| − | y, & \text{if | + | y, & \text{ if } x = 1 \\ |
| − | z, & \text{if | + | z, & \text{ if } x = 0 |
\end{cases} | \end{cases} | ||
</math> | </math> | ||
| Line 24: | Line 24: | ||
Which can be implemented as: | Which can be implemented as: | ||
| − | <math> | + | ::<math> |
| − | + | \text{Ch}(x,y,z) = (x \land y) \lor (\bar x \land z) | |
| + | </math> | ||
| + | The xor version is sometimes more commonly in field such as [[cryptography]]. | ||
| + | ::<math> | ||
| + | \text{Ch}(x,y,z) = (x \land y) \oplus (\bar x \land z) | ||
</math> | </math> | ||
Latest revision as of 21:07, 15 December 2015
| Inputs | Outputs | ||
|---|---|---|---|
| X | Y | Z | Q |
| 0 | X | 0 | 0 |
| 0 | X | 1 | 1 |
| 1 | 0 | X | 0 |
| 1 | 1 | X | 1 |
Choose function (or Ch Function) (sometimes if-then-else or ITE) is a Boolean function that represents a 2:1 MUX. The choose function is frequently found in various cryptographic hash functions.
Which can be implemented as:
The xor version is sometimes more commonly in field such as cryptography.
See also[edit]
- rotate left (ROL)
- rotate right (ROR)
- parity function (PAR)
- majority function (MAJ)