# builtin

ZK WorldVM implements built-in functionality to support range checking, hashing, etc. Built-in code needs to be encoded in the instruction set, which is defined in the built-in row of Table 3.

### Sand scab range check

The range checking builtin is used to check data of type u32. When performing range checking builtin, ZK WorldVM puts the checking data into the range checking tracking table

### Bitwise

Bit built-ins are used to implement sum x or triple-bit operations on u32 type data. ZK WorldVM runs the built-in logic and puts the result of the operation into a bitwise tracking table. At the same time, put the two source operands into the range check tracking table.

### Sand scab comparison

The compare builtin is used to implement gte (greater or equal) comparisons. ZK WorldVM runs built-in logic and operation results into a comparison tracking table. Tracking table reference: Table 13 At the same time, put the two source operands into the range checking tracking table.
