Wednesday, March 23, 2016

8051 Exchange Digit

XCHD exchanges the low-order nibble of the Accumulator (bits 3 through 0), generally representing a hexadecimal or BCD digit, with that of the internal RAM location indirectly addressed by the specified register. The high-order nibbles (bits 7-4) of each register are not affected. No flags are affected.

Encoding: 1 1 0 1 0 1 1 i

R0 contains the address 20H. The Accumulator holds the value 36H (00110110B). Internal RAM location 20H holds the value 75H (01110101B). The following instruction,

XCHD A,@R0

leaves RAM location 20H holding the value 76H (01110110B) and 35H (00110101B) in the Accumulator



Related topics:
8051 Complement Accumulator and Bit   |   8051 Set Bit   |   8051 Clear Accumulator and Bit   |   8051 Rotate Accumulator   |   8051 Swap Nibble   |   8051 Exchange Accumulator   |   8051 Push and Pop   |   8051 No Operation

List of topics: 8051

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