1. Using XCHG operation
Instruction Comment
LXI H, D000 H ; HL pointing to D000 H
LXI D, D001 H ; DE pointing to D001 H
MOV B, M ; B (HL) (first byte)
LDAX D ; Load second byte in ACC.
XCHG ; Exchange DE and HL pair contents.
MOV M, B ; Store first byte in second location
STAX D ; Store second byte in first location.
HLT ; Stop
Foot note:
The XCHG memonic can only be used for exchanging contents of DE and HL pair. So for exchanging the contents of any two memory location its better to make DE and HL as memory pointer.
2. Without using XCHG operation.
Instruction Comment
LXI H,D000H ; HL pointing to D000H
LXI B,D001H ; BC pointing to D001H
MOV D,M ; Move the contents of M to D
LDAX B ; Move the contents of BC to Accumulator
MOV M,A ; Move the contents of BC to HL
STAX D ; Move the contents of HL to BC
HLT ; Stop
