larc in logisim Flashcards
how can complicated logic gates store & execute computer programs
computers can chain logic gates together by connecting the output of one into the input of another. this allows for more complex operations than a single gate
(overall structure) how many general-purpose registers?
16
(overall structure) each register holds?
16-bit binary number
(overall structure) general-purpose registers are numbers
0-15 or 0b0000 to 0b1111 in binary
(overall structure) register 0 is always
0
(overall structure) fetch-and-execute cycle
16-bit number in PC gives address of memory location that contains next ML instruction –> computer fetches instruction from address –> adds one to PC for next instruction –> executes instruction –> repeats until halted
(overall structure) what goes inside larc computer
- PC
- ROM
- Register file
- ALU
- RAM
- Clock
role of the clock
signal that keeps control unit moving
at each clock ‘tick’
control unit moves to next machine cycle (next instruction / next phase of current instruction)
clock generator cycle
based on crystal oscillator, generates regular sequence of 0 & 1 logic
one clock cycle
tick –> rising edge –> tock –>falling edge
program counter (PC)
register that holds counter / current # of steps of program; when program is executed, +1 is added, proceeds to next instruction
(structure of register file) registers are memory used to
accept, store, & transfer data/instructions being used immediately by CPU
(structure of register file) important functions of registers
fetching, decoding, & execution
(structure of register file) data register do what?
hold numbers, characters, & arrays
