ZiLOG Z8 Technical Manual

JR
Jump Relative
JR cc,dst
Instruction Foraat:
Cycles
OPC
(Hex)
Address Mode
dot
~ __ cc ____ ~ __ O_p_C __ ~1 I~ ______ d_s_t ______ ~
12 If jump taken ccB
10 If jump not taken
RA
Operation:
Flags:
Example:
5-26
cc=O to F
If cc is true, PC <-- PC + dst
If the condition specified by "cc" is true, the relative address is added to the
PC and control passes to the statement whose address in now in the PC; otherwise, the
instruction following the JR instruction is executed. (See Section 5.3 for a list of
condition codes). The range of the relative address is +127, -128, and the original
value of the PC is taken to be the address of the first instruction byte following
the JR statement.
No flags affected
If the result of the last arithmetic operation executed is negative, the following
four statements (which occupy a total of seven bytes) are skipped with the statement
JR MI,$+9
If the result is not negative, execution continues with the statement following the
JR. A short form of a jump to label LO is
JR LO
where LO must be within the allowed range. The condition code is "blank" in this
case, and is assumed to be "always true."

ZiLOG Z8 Specifications

General

Brand	ZiLOG
Model	Z8
Category	Desktop
Language	English