<< Previous | Next >>

LDD
LDI     Byte Copy     Rabbit 2000/3000/4000/5000 Instruction

Opcode	Instruction	Operation
ED A8	LDD	(DE) = (HL) BC = BC - 1 DE = DE - 1 HL = HL - 1
ED A0	LDI	(DE) = (HL) BC = BC - 1 DE = DE + 1 HL = HL + 1

Clocks	8-Bit Access	16-Bit Unaligned	16-Bit Aligned
Rabbit 2000/3000/4000	10	n/a	n/a
Rabbit 5000	10	10	8

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

Description

• LDD: Loads the memory location whose address is DE with the data at the address in HL. Then it decrements the value in BC, DE, and HL.

• LDI: Loads the memory location whose address is DE with the data at the address in HL. Then the value in BC is decremented and the value in DE and HL is incremented.

If either instruction is prefixed by IOI or IOE, the destination will be in the specified I/O space. Add 1 clock for each iteration if the prefix is IOI (internal I/O). If the prefix is IOE, add 2 clocks plus the number of I/O wait states enabled. The V flag is cleared when BC transitions from 1 to 0.