Assume the PC has the address 0x021A when FETCH INSTRUCTION phase begins. After that first instruction executes, which one describes the second instruction to execute? a) LDR R4 with a value from memory b) LDR R5 with a value from memory c) ADD R4 to R5 and save result in R7 d)

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Assume the PC has the address 0x021A when FETCH INSTRUCTION phase begins. After that first instruction executes, which one describes the second instruction to execute?

a) LDR R4 with a value from memory

b) LDR R5 with a value from memory

c) ADD R4 to R5 and save result in R7

d) 

The following assumes the LC-3 architecture.

Consider the following table that represents several of the 16-bit registers in the register file:

| Register | CONTENTS (binary)     |
|----------|-----------------------|
| R0       | 0000 0011 0001 1110   |
| R1       | 0000 0011 0010 0000   |
| R2       | 0000 0011 0010 0001   |
| ...      | ...                   |

Also consider the following table that represents part of the memory of a 16-bit address space that has an addressability of 2 bytes:

| ADDRESS (hex) | CONTENTS (binary)        |
|---------------|--------------------------|
| ...           | ...                      |
| 0x0321        | 0001 1111 0000 0101      |
| 0x0320        | 0001 1111 0100 0110      |
| 0x031F        | 0110 1010 1100 0100      |
| 0x031E        | 0110 1000 1101 0101      |
| ...           | ...                      |
| 0x021C        | 1100 0000 0000 0000      |
| 0x021B        | 1100 0000 1000 0000      |
| 0x021A        | 1100 0000 0100 0000      |
| ...           | ...                      |

Assume the PC has the address 0x021A when the FETCH INSTRUCTION phase begins. After that first instruction executes, which one describes the second instruction to execute?
Transcribed Image Text:The following assumes the LC-3 architecture. Consider the following table that represents several of the 16-bit registers in the register file: | Register | CONTENTS (binary) | |----------|-----------------------| | R0 | 0000 0011 0001 1110 | | R1 | 0000 0011 0010 0000 | | R2 | 0000 0011 0010 0001 | | ... | ... | Also consider the following table that represents part of the memory of a 16-bit address space that has an addressability of 2 bytes: | ADDRESS (hex) | CONTENTS (binary) | |---------------|--------------------------| | ... | ... | | 0x0321 | 0001 1111 0000 0101 | | 0x0320 | 0001 1111 0100 0110 | | 0x031F | 0110 1010 1100 0100 | | 0x031E | 0110 1000 1101 0101 | | ... | ... | | 0x021C | 1100 0000 0000 0000 | | 0x021B | 1100 0000 1000 0000 | | 0x021A | 1100 0000 0100 0000 | | ... | ... | Assume the PC has the address 0x021A when the FETCH INSTRUCTION phase begins. After that first instruction executes, which one describes the second instruction to execute?
**Task Overview:**

Assume the PC has the address 0x021A when the FETCH INSTRUCTION phase begins. After that first instruction executes, which one describes the second instruction to execute?

**REFERENCE:**

**Table of LC-3 Instructions:**

| Opcode | 15 | 14 | 13 | 12 | 11 | 10 | 9  | 8  | 7  | 6  | 5 | 4  | 3  | 2  | 1  | 0  |
|--------|----|----|----|----|----|----|----|----|----|----|---|----|----|----|----|----|
| ADD    | 0  | 0  | 0  | 1  | DST| SRC1 | 0  | 0  | 0 | SRC2 |
| JMP    | 1  | 1  | 0  | 0  | 0  | Base | 0  | 0  | 0 | 0  | 0  | 0  |
| LDR    | 0  | 1  | 1  | 0  | DST| Base | Offset |

**Answer Choices:**

- ○ LDR R4 with a value from memory
- ○ LDR R5 with a value from memory
- ○ ADD R4 to R5 and save result in R7
- ○ ADD R5 to R6 and save result in R7

**Diagram Explanation:**

The table outlines the instruction set for a hypothetical LC-3 processor, showing how the bits in an instruction word determine the operation to perform. The instruction consists of an opcode field defined by bits 15 to 12, followed by operand fields.

1. **ADD Instruction:**
   - Bits 15-12 are `0001`
   - The instruction formats an addition operation with destination (`DST`), and source registers (`SRC1` and `SRC2`).

2. **JMP Instruction:**
   - Bits 15-12 are `1100`
   - Used for jumping to a location specified by a base register (`Base`).

3. **LDR Instruction:**
   - Bits 15-12 are `0110`
   - Loads a value from memory into a destination register (`DST`) using the base register (`Base`)
Transcribed Image Text:**Task Overview:** Assume the PC has the address 0x021A when the FETCH INSTRUCTION phase begins. After that first instruction executes, which one describes the second instruction to execute? **REFERENCE:** **Table of LC-3 Instructions:** | Opcode | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |--------|----|----|----|----|----|----|----|----|----|----|---|----|----|----|----|----| | ADD | 0 | 0 | 0 | 1 | DST| SRC1 | 0 | 0 | 0 | SRC2 | | JMP | 1 | 1 | 0 | 0 | 0 | Base | 0 | 0 | 0 | 0 | 0 | 0 | | LDR | 0 | 1 | 1 | 0 | DST| Base | Offset | **Answer Choices:** - ○ LDR R4 with a value from memory - ○ LDR R5 with a value from memory - ○ ADD R4 to R5 and save result in R7 - ○ ADD R5 to R6 and save result in R7 **Diagram Explanation:** The table outlines the instruction set for a hypothetical LC-3 processor, showing how the bits in an instruction word determine the operation to perform. The instruction consists of an opcode field defined by bits 15 to 12, followed by operand fields. 1. **ADD Instruction:** - Bits 15-12 are `0001` - The instruction formats an addition operation with destination (`DST`), and source registers (`SRC1` and `SRC2`). 2. **JMP Instruction:** - Bits 15-12 are `1100` - Used for jumping to a location specified by a base register (`Base`). 3. **LDR Instruction:** - Bits 15-12 are `0110` - Loads a value from memory into a destination register (`DST`) using the base register (`Base`)
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