>>72 The contents of register C are placed on the bottom half (A0 through A7) of the address bus to select the I/O device at one of 256 possible ports. The contents of Register B are placed on the top half (A8 through A15) of the address bus at this time.
>>77 > The contents of Register B are placed on the top half (A8 through A15) of the > address bus at this time. > レジスターBの内容は、アドレスバスのトップの半分(A15によるA8)にこの時期に置かれます。
OUT (n), A Description: The operand n is placed on the bottom half (A0 through A7) of the address bus to select the I/O device at one of 256 possible ports. The contents of the Accumulator (register A) also appear on the top half (A8 through A15) of the address bus at this time. Then the byte contained in the Accumulator is placed on the data bus and written to the selected peripheral device.
OUT (C), r Description: The contents of register C are placed on the bottom half (A0 through A7) of the address bus to select the I/O device at one of 256 possible ports. The contents of Register B are placed on the top half (A8 through A15) of the address bus at this time. Then the byte contained in register r is placed on the data bus and written to the selected peripheral device. Register r identifies any of the CPU registers shown in the following table, which also shows the corresponding three-bit r field for each that appears in the assembled object code: