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.

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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