Error on slide 37 from lecture 5.pdf?

[piglin]

There seems to be an error on slide 37 (lecture 5.pdf).

The inputs od Mux16 that routes the instruction's MSB are in reversed order compared to a quote from the book:

"This 16-bit value represents either an A-instruction (when the leftmost bit is 0) or a C-instruction (when the leftmost bit is 1)."

The screenshot from the lecture shows that A-instruction is when c=1, and C-instruction is when c=0.

[dolomiti7]

How do you come to that conclusion? The Mux on the left side clearly shows that in case of c=0 the instruction itself is selected as input for the A-Register. So the value of the A-instruction is routed to the A-Register as intended. Due to the c-bit=0, the representation of the A-Instruction is equivalent to its value.

In case of c=1, the output of the ALU is instead selected as input to the A-Register. The only thing that might be confusing is that in the chart in this case the upper input signal is linked to c=1 which is the opposite of the usual order. However, it is clearly marked in the chart.

[piglin]

> How do you come to that conclusion?

By misunderstanding the diagram. For some reason I thought the A-instruction comes from ALU output and C-instruction comes from, well, instruction... :)

Thanks for taking the time to point to my false logic.