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> ## Chapter 2. Rabbit Processor Registers

> The registers of the Rabbit family of microprocessors can be divided into two categories: processor registers and I/O registers. That last category can be divided further: parallel port registers, serial port registers, memory control registers, timer registers, etc. Information on I/O registers can be found in the Rabbit chip manuals and in the Dynamic C help file, accessible by selecting "I/O Registers" from the help menu.

> The registers discussed in this chapter are the processor registers. These are the registers that are used in the Rabbit instruction set.

> ## 2.1 Rabbit 2000/3000 Processor Registers

> The Rabbit 2000 and 3000 microprocessors have identical processor register sets. The following table provides details.

> Table 1. Rabbit 2000/3000 Register Set

> Registers | 8-Bit | 16-Bit | Alternate Register
> Accumulators | A | HL | A´, HL´
> Flags1 | F |  | F'
> General Purpose | B, C, D, E, H, L | BC, DE | B´, C´, D´, E´, H´, L´ BC´, DE´
> Index |  | IX, IY | None
> Stack Pointer |  | SP | None
> Program Counter |  | PC | None
> Xmem Program Counter | XPC |  | None
> Interrupt Priority | IP |  | None
> Internal Interrupt | IIR |  | None
> External Interrupt | EIR |  | None

> 1 S=Sign, Z=Zero, LV=Logical/Overflow, C=Carry. Bits marked "x" are reserved for future use.

> Flag Bits

> ## 2.2 Rabbit 4000 Processor Registers

> The Rabbit 4000 has a expanded register set over the previous two versions of the Rabbit chip.

> .

> Table 2. Rabbit 4000 Register Set

> Registers | 8-Bit | 16-Bit | 32-Bit | Alternate Registers
> Accumulators | A | HL |  | A´, HL´
> Flags1 | F |  |  | F´
> General Purpose | B, C, D, E, H, L | BC, DE, JK | BCDE, JKHL | B´, C´, D´, E´, H´, L´ BC´, DE´, JK´ BCDE´, JKHL´
> Index |  | IX, IY | PW, PX, PY, PZ | PW´, PX´, PY´, PZ´
> Stack Pointer |  | SP |  | None
> Program Counter |  | PC |  | None
> Xmem Program Counter | XPC | XPC (low 12 bits valid) |  | None
> Interrupt Priority | IP |  |  | None
> Internal Interrupt | IIR | SP |  | None
> External Interrupt | EIR | PC |  | None
> System/User Mode | SU |  |  | None
> Handle Table Register | HTR |  |  | None

> 1 S=Sign, Z=Zero, LV=Logical/Overflow, C=Carry. Bits marked "x" are reserved for future use.

> Flag Bits

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