Zilog Z80380 Bedienungsanleitung PDF herunterladen (Seite 184)

5-150

Z380

™

USER'S MANUAL

DC-8297-03

ZILOG

RLD

ROTATE LEFT DIGIT

RLD

Operation: tmp(3-0) ← A(3-0)

A(3-0) ← dst(7-4)

dst(7-4) ← dst(3-0)

dst(3-0) ← tmp(3-0)

The low digit of the accumulator is logically concatenated to the destination byte whose

memory address is in the HL register. The resulting three-digit quantity is rotated to the left

by one BCD digit (four bits). The lower digit of the source is moved to the upper digit of the

source; the upper digit of the source is moved to the lower digit of the accumulator, and the

lower digit of the accumulator is moved to the lower digit of the source. The upper digit of

the accumulator is unaffected. In multiple-digit BCD arithmetic, this instruction can be used

to shift to the left a string of BCD digits, thus multiplying it by a power of ten. The accumulator

serves to transfer digits between successive bytes of the string. This is analogous to the use

of the Carry flag in multiple-precision shifting using the RL instruction.

Flags: S: Set if the accumulator is negative after the operation; cleared otherwise

Z: Set if the accumulator is zero after the operation; cleared otherwise

H: Cleared

P: Set if the parity of the accumulator is even after the operation; cleared otherwise

N: Cleared

C: Unaffected

Addressing Execute

Mode Syntax Instruction Format Time Note

RLD 11101101 01101111 3+r

1 2 ... 179 180 181 182 183 184 185 186 187 188 189 ... 267 268

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Zilog Z80380 Bedienungsanleitung Seite 184