Test and jump instructions

The IBM 51x0 processor doesn't have a status register like most other microprocessors that stores different flags reflecting the status of a previous operation. So there are no conditional jumps that could test e.g. the zero flag or the overflow flag. And there can't be any instruction that explicitly modifies the flags.
Instead this processor implements a combination of test and skip instructions that compare one or two registers and then decides whether to skip the following instruction or not.

The different skip instructions

Note: All compares are done with the low order byte of the registers except where stated otherwise.