COA Presentation 4 ADDRESSING MODES.pptx

COA

1. UITC003 – COMPUTER ORGANIZATION AND ARCHITECTURE COA PPT4 ADDRESSING MODES 1 ADDRESSING AND ADDRESSING MODES

2. MIPS Addressing Mode Multiple forms of addressing are generically called addressing modes Varied based on the operands we use Immediate addressing Register addressing Base or displacement addressing PC-relative addressing Pseudodirect addressing COA PPT4 ADDRESSING MODES 2

3. MIPS Addressing Mode 1 Immediate addressing: where the operand is a constant within the instruction itself In mode 1, the operand is 16 bits of the instruction itself The operands are shaded in color. COA PPT4 ADDRESSING MODES 3

4. MIPS Addressing Mode 2 Register addressing: Where the operand is a register COA PPT4 ADDRESSING MODES 4

5. MIPS Addressing Mode 3 Base or displacement addressing: W here the operand is at the memory location whose address is the sum of a register and a constant in the instruction COA PPT4 ADDRESSING MODES 5

6. MIPS Addressing Mode 4 PC-relative addressing: W here the branch address is the sum of the PC and a constant in the instruction Address instructions in memory, with mode 4 adding a 16-bit address shifted left 2 bits to the PC COA PPT4 ADDRESSING MODES 6

7. MIPS Addressing Mode 5 Pseudodirect addressing Where the jump address is the 26 bits of the instruction concatenated with the upper bits of the PC mode 5 concatenating a 26-bit address shifted left 2 bits with the 4 upper bits of the PC COA PPT4 ADDRESSING MODES 7

8. Note: Single operation can use more than one addressing mode. Add, for example, uses both immediate ( addi ) and register (add) addressing. COA PPT4 ADDRESSING MODES 8