Final answer:
To determine the bit pattern in register 1 when the machine halts, one would need to simulate the program's execution step by step. However, additional context on the machine's instruction set is required to accurately complete this simulation.
Step-by-step explanation:
The question pertains to the execution of a program in the hypothetical machine's memory with specific instructions at memory addresses. The goal is to determine the bit pattern in register 1 when the machine halts. To provide an answer, one would need to simulate the execution step by step based on the specific machine code instructions provided.
However, sufficient information about the machine's instruction set (e.g., what operations are represented by the codes 20, 21, 40, etc.) is necessary to interpret these instructions and carry out this simulation. Without this context, we cannot determine what the machine will do with these instructions or what the bit pattern in register 1 will be when the machine halts.