ZiLOG eZ80 User Manual page 333

RRD
Rotate Right Decimal
Operation
A
7
A[3:0] ← HL[3:0]
HL[7:4] ← A[3:0]
HL[3:0] ← HL[7:4]
Description
The CPU copies the contents of the low-order four bits of the memory location (HL) into
the low-order four bits of the accumulator, A. The CPU next copies the previous contents
of the low-order four bits of the accumulator into the high-order four bits of (HL). The
CPU next copies the previous contents of the high-order four bits of (HL) into the low-
order four bits of (HL).
Condition Bits Affected
S
Z
H
P/V
N
C
Attributes
Mnemonic Operand
RRD
UM007714-0908
4 3 0
Set if the accumulator is negative; reset otherwise.
Set if the accumulator is 0; reset otherwise.
Reset.
Set if parity of the accumulator is even; reset otherwise.
Reset.
Not affected.
ADL Mode Cycle Opcode (hex)
— X
4 3 0 (HL)
7
5
ED, 67
®
eZ80 CPU
User Manual
324
CPU Instruction Set