Tuesday, February 16, 2010

Addressing Techniques

VI. Addressing Techniques


Addressing Modes

Z – 80 Addressing


Implied - the data value/data address is implicitly associated with the instruction.

Register - references the data in a register or in a register pair.

Register indirect - instruction specifies a register containing an address, where data is located.

Immediate - 8-bit data is provided in the instruction.

Immediate extended - 16-bit data is provided in the instruction.

Modified page zero - the destination address in zero page is calculated as N * 8, where N is a three-bit number supplied by the instruction.

Relative - one byte offset is added to the address of the next instruction. The offset is a signed number in the range -127 - +128.

Extended - the instruction operand specifies the memory address where data is located and where the program control should be transferred.

Indexed - 8-bit offset is added to the contents of an index register (IX or IY), the resulting value is a pointer to location where data resides.


VII. Basic Programming Techniques

Arithmetic programs

BCD Arithmetic Multiplication

Subroutines

Logic Operation etc.

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