LC-3架构C++实现调试求助：首条LD指令执行异常

架构老林

2026-8-1

LC-3模拟器LD指令执行异常调试求助

我正在用C++实现LC-3架构，参考了一份C语言的LC-3虚拟机教程。代码已经写完，编译运行时传入待执行的obj文件，但卡在了首条LD指令的执行环节。

首条指令（LD）的执行代码如下：

case Registry::OP_LD:
{
    uint16_t r0 = (instr >> 9) & 0x7;
    uint16_t pc_offset = m_registry->sign_extend(instr & 0x1FF, 9);

    printf("m_memory: %p\n", m_memory);
    printf("m_registry: %p\n", m_registry);
    printf("\n\n\n\n\n\n");
    printf("m_memory[0]: %d\n", m_memory->read(0));
    printf("m_registry[0]: %d\n", m_registry->get(0));
    printf("\n\n\n\n\n\n");
    printf("R0: %d\n", r0);
    printf("pc_offset: %d\n", pc_offset);
    printf("Reg 0: %d\n", m_registry->get(r0));
    printf("mem read: %d\n", m_memory->read(m_registry->get(static_cast<uint16_t>(Registry::R_PC)) + pc_offset));
    m_registry->set(r0, m_memory->read(m_registry->get(static_cast<uint16_t>(Registry::R_PC)) + pc_offset));
    printf("Reg 0 bis: %d\n", m_registry->get(r0));
    m_registry->update_flags(r0);
}

添加printf调试后，部分输出如下：