Arithmetic // RLD (Rotate Left bcd Digit)
The contents of the low-order four bits (bits 3, 2, 1, and 0) of the memory location (HL) are copied to the high-order four bits (7, 6, 5, and 4) of that same memory location; the previous contents of those high-order four bits are copied to the low-order four bits of the Accumulator (Register A); and the previous contents of the low-order four bits of the Accumulator are copied to the low-order four bits of memory location (HL). The contents of the high-order bits of the Accumulator are unaffected. Note:(HL) refers to the memory location specified by the contents of the HL register pair.
The HL register pair contains 5000h and the Accumulator and memory location 5000h contain the following data. 76534 2 10 01111 0 10Accumulator 76534 2 10 00101 0 01(5000h) Upon the execution of an RLD instruction, the Accumulator and memory location 5000h now contain: 76534 2 10 01101 0 11Accumulator 76534 2 10 00011 0 10(5000h)