Comments on: I’m not dead, really

by: zoku88

Sun, 11 Jan 2009 19:46:13 +0000

The instruction set was made for us. And we actually made the ALU in a previous lab near the beginning of the semester.

It probably looks harder than it actually was.

by: SS

Thu, 08 Jan 2009 04:25:49 +0000

Oh, wow. How long did you have to work on this project? It dwarfs the kind of work we did in my microprocessor class by far. Did you make a minimal ISA or anything?

by: zoku88

Wed, 07 Jan 2009 22:52:43 +0000

We had to make the reg file and the ALU and everything in there except for the memory stuff.

The control logic was mainly just a ROM although there is some combinational logic stuff I put in there to make it a bit faster.

JT is jump taken. It’s the address of the line that is next when you jump.

The address to jump comes from the line that says PC + 4 + 4*C when you’re doing a (relative) branch.

For the address for a jump, it actually comes from the reg file (right under RD1. RD1 is JT in this case.)

by: SS

Wed, 07 Jan 2009 21:10:44 +0000

(I know this post is old)
That’s cool, IMO! I assume you got to take the register file, ALU etc. for granted and just had to piece them together? Still pretty impressive…looks like you’ve even got some interrupt action going on there. Did you have to implement anything for the control logic? Is JT “Jump Taken”? I’m not quite sure where the address from the ALU gets to the PC, though…