The MIPS Architecture

• Take a look at the green sheet.
• Also, the information on page 64 is really useful too.
  • MIPS has 32 registers
    • How are these used in instructions?
      • Look at add
      • Look at addi
      • Look at lw/sw
    • There is a box in the bottom right that describes register use
      • Don't worry too much right now but note
        • $zero
        • $at
        • $gp, $sp, $fp, $ra
    • How are they accounted for in the instruction format?
• What happens to the values in the registers?
  • Where does the selection of a register come from?
  • Where does the value of a register go?
  • Look at the picture on page 263
• We need a new piece of hardware, a decoder
  • In TK-Gate
  • A decoder has n bits of input
  • and 2ⁿ output lines.
  • The value on the input is used to select the appropriate output.
  • Oh, it also has an enable line
  • 
  • The example file.
• Can we build the register file?
  • What are the inputs?
  • What are the outputs? (Page 263 if nothing else)
  • Let us reduce this to a 4 register system.
  • Let us reduce it to an 8 bit register as well.
  • How many bits on the input/output lines.
  • 
  • The implementation file.