Zilog EZ80F916 - Manual (Page 333)

eZ80
®
CPU
User Manual
UM007715-0415 CPU Instruction Set
324
RRD
Rotate Right Decimal
Operation
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
Attributes
S
Set if the accumulator is negative; reset otherwise.
Z
Set if the accumulator is 0; reset otherwise.
H
Reset.
P/V
Set if parity of the accumulator is even; reset otherwise.
N
Reset.
C
Not affected.
Mnemonic Operand ADL Mode Cycle Opcode (hex)
RRD
— X 5
ED, 67
3 7 4 0 3 7 4 0 (HL) A