SAM47 INSTRUCTION SET KS57C2308/P2308/C2316/P2316
5-92
XCHI — Exchange and Increment
XCHI dst,src
Operation: Operand Operation Summary Bytes Cycles
A,@HL Exchange A and data memory contents; increment
contents of register L and skip on overflow 12 + S
Description: The instruction XCHI exchanges the contents of the accumulator with the RAM location
addressed by register pair HL and then increments the contents of register L. If the content of
register L is 0H, a skip is executed. The value of the carry flag is not affected.
Operand Binary Code Operation Notation
A,@HL 01111010A ↔ (HL), then L ← L+1;
skip if L = 0H
Example: Register pair HL contains the address 2FH and internal RAM location 2FH contains 0FH:
LD HL,#2FH
LD A,#0H
XCHI A,@HL ;A ← 0FH and L ← L + 1 = 0, (HL) ← "0"
JPS XXX ;Skipped since an overflow occurred
JPS YYY ;H ← 2H, L ← 0H
YYY XCHI A,@HL ;(20H) ← 0FH, A ← (20H), L ← L + 1 = 1H
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The “JPS YYY” instruction is executed since a skip occurs after the XCHI instruction.