The CPU contains a set of configuration registers that control some aspects of the CPU, such as the stack. There is room for up to 256 8 bit registers, but only a few are currently defined.
| Index | Content |
|---|---|
| $00 | AF stack pointer |
| $01 | BC stack pointer |
| $02 | DE stack pointer |
| $03 | HL stack pointer |
| $04 | Stack lower bound |
| $05 | Stack upper bound |