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JRE cx,label     Jump Relative     Rabbit 4000/5000 Instruction

Opcode	Instruction	Operation
----	JRE cx,label JRE cx,mn1	if {cx} PC = PC2 + ee
ED A3 ee low eehigh	JRE GT,mn	if {GT} PC = PC + ee
ED B3 ee low eehigh	JRE LT,mn	if {LT} PC = PC + ee
ED AB ee low eehigh	JRE GTU,mn	if {GTU} PC = PC + ee
ED BB ee low eehigh	JRE V,mn	if {V} PC = PC + ee

1 The 16-bit constant mn is the destination logical address of the jump 2 The value of PC after the instruction fetch.

Clocks	8-Bit Access	16-Bit Unaligned	16-Bit Aligned
Rabbit 4000	9	n/a	n/a
Rabbit 5000	10	10	10

Flags				ALTD			IOI/IOE
S	Z	L/V	C	F	R	SP	S	D
-	-	-	-

Description

If condition "cx" is true, this instruction transfers control to the specifed address. The address is specified by a label or logical address. The assembler translates the label or logical address "mn" to a 16-bit signed displacement value, "ee".

The displacement value "ee" is relative to the address of the first byte of the instruction following JRE. This fact is because the processor calculates the new PC value after it increments the PC for the instruction fetch of JRE. If condition "cx" is not true, PC is incremented normally.

Condition Code	Flag Bit Value	Description
GT	(Z or (S xor V))=0	True when Z is 0 and L/V and S are either both 1 or both 0.
LT	(S xor V)=1	True when either S is 1 or L/V is 1.
GTU	((C=0) and (Z=0))=1	True when C and Z are both 0.
V	L/V=1	True when L/V flag is set: there is overflow.

Note that the relative jump has a range of [-32768, 32767] from the address of the first byte of the instruction following the JRE instruction.