CS 352 Lecture 17 – Catchup
Dear students,
Last week lots of good misunderstandings of memory came up. When misunderstandings appear, the right things are happening. Conflict surfaces in your brain, which is step 1 of learning. Step 2 is resolving that conflict. Today, then, I want to start by revisiting some ideas of how memory and pointers work in C and really in the entire computer.
I will unveil the following programming one line at a time. Your job is to determine what’s happening.
0: int a[] = {65535, 991, 992, 993}; 1: printf("%d\n", a); 2: printf("%d\n", *a); 3: printf("%d\n", &a[1]); 4: printf("%d\n", a + 3); 5: printf("%d\n", 2[a]); 6: int *p = a; 7: printf("%d\n", p); 8: printf("%d\n", &p); 9: printf("%d\n", *p); 10: unsigned char *b = (unsigned char *) a; 11: printf("%d\n", *b); 12: printf("%d\n", *(b + 1)); 13: printf("%d\n", *(b + 2)); 14: printf("%d\n", *(b + 3));
Some folks have expressed confusion about HDL and n-way components. Also, the next homework requires doing some HDL tricks that I don’t think are necessarily intuitive. Rather than continuing to build on a wobbly foundation, let’s sketch out schematics for some of these components and translate them to HDL. We’ll visit these: Mux4Way, DMux4Way, Inc16, LeastByte (which is not part of any homework), ALU, Bit, Register, RAM8, RAM64, and PC.
See you next class!
