Feynman Lectures on Computation: Solutions

Wed, 11 Jun 2025 00:00:00 +0000

Before we start, please note that these are my solutions, not the solutions.

Chapter 1

For future reference:

Available on the pad:

Available Instructions:

Data Transfer: $A \leftarrow (M)$, $M \leftarrow (A)$, $B \leftarrow (M)$, $M \leftarrow (B)$, $X \leftarrow (B)$, $B \leftarrow (X)$, $PC \leftarrow (X)$, $X \leftarrow (PC)$
Arithmetic: $A \leftarrow 0$ (Clear A), $A \leftarrow (A) + (B)$ (Add), $A \leftarrow (A) + 1$ (Increment), $A \leftarrow (A) - 1$ (Decrement)
Bit Operations: Shift Left A, Shift Right A
Logical: $A \leftarrow (A) \land (B)$ (AND), $A \leftarrow (A) \lor (B)$ (OR), $A \leftarrow (A) \oplus (B)$ (XOR)
Direct Load: $B \leftarrow N$ (load constant N), $M \leftarrow 0$ (Clear memory location)
Control Flow: $PC \leftarrow (Z)$ (Jump), $PC \leftarrow (Z)$ if $C=1$ (Conditional Jump), $PC \leftarrow (PC) + (Z)$ (Relative Jump)
Special: Halt

NB: In what follows, I am a bit more liberal with the instructions. I sometimes shift $X$ instead of $A$, etc.