{"id":178,"date":"2017-08-11T14:24:25","date_gmt":"2017-08-11T06:24:25","guid":{"rendered":"http:\/\/www.sinkland.cn\/?p=178"},"modified":"2019-08-17T15:05:21","modified_gmt":"2019-08-17T07:05:21","slug":"smlos%e5%8d%81%e4%b8%80-%e5%a4%9a%e4%bb%bb%e5%8a%a1%e6%94%af%e6%8c%81","status":"publish","type":"post","link":"http:\/\/www.sinkland.cn\/?p=178","title":{"rendered":"SmlOS\u5341\u4e00-\u591a\u4efb\u52a1\u652f\u6301"},"content":{"rendered":"

\u64cd\u4f5c\u7cfb\u7edf\u662f\u5982\u4f55\u5b9e\u73b0\u4efb\u52a1\u5e76\u884c\u7684<\/h3>\n

\n \u8fd9\u91cc\u7684\u4efb\u52a1\u53ef\u4ee5\u7406\u89e3\u6210\u8fdb\u7a0b\u6216\u8005\u7ebf\u7a0b\u64cd\u4f5c\n<\/p><\/blockquote>\n

\u4e0d\u77e5\u9053\u6709\u6ca1\u6709\u540c\u5b66\u5bf9\u6b64\u8868\u793a\u8fc7\u597d\u5947\uff0c\u591a\u4e2a\u8fdb\u7a0b\u5982\u4f55\u505a\u5230\u540c\u65f6\u8fd0\u884c\u4e14\u4e0d\u76f8\u4e92\u5f71\u54cd\u7684\u3002<\/p>\n

\u4e5f\u8bb8\u64cd\u4f5c\u7cfb\u7edf\u8bfe\u4e0a\u6709\u8fd9\u6837\u89e3\u91ca\u8fc7\uff0c\u4e24\u4e2a\u4efb\u52a1\u7ebf\u7a0b\u4e0d\u505c\u7684\u5feb\u901f\u5207\u6362\uff0c\u770b\u8d77\u6765\u5c31\u50cf\u662f\u540c\u65f6\u8fd0\u884c\u4e86\u4e00\u6837\u3002<\/p>\n

\u8bf4\u7684\u6ca1\u9519\uff0c\u4e0d\u8fc7\u53ea\u6709\u4eb2\u81ea\u5b9e\u73b0\u4e00\u904d\uff0c\u624d\u80fd\u5bf9\u6b64\u6709\u6df1\u523b\u7684\u7406\u89e3\u3002<\/p>\n

\n

\u65f6\u95f4\u7247\u8f6e\u8f6c<\/h3>\n

\u5148\u6765\u8bf4\u4e0b\u4efb\u52a1\u5207\u6362\u7684\u539f\u7406\uff0c\u5176\u5b9e\u5f88\u7b80\u5355\u3002<\/p>\n

\u5047\u5982\u6211\u4eec\u6709\u53ea\u6709\u4e24\u4e2a\u4efb\u52a1A\u548cB\uff0c\u6bcf\u4e2a\u4efb\u52a1\u7684\u65f6\u95f4\u7247\u662f100ms\u3002<\/p>\n

\u521a\u5f00\u59cb\u662fA\u5728\u8fd0\u884c\uff0c\u8fc7\u4e86100ms\uff0c\u7531\u65f6\u949f\u4e2d\u65ad\u6253\u65ad\u4e86\uff0c\u5728\u4e2d\u65ad\u4e2d\uff0c\u628aA\u6240\u6709\u7684\u5bc4\u5b58\u5668\u7684\u503c\u4fdd\u5b58\u5728\u4e00\u4e2a\u5730\u65b9\uff0c\u8fd9\u4e2a\u64cd\u4f5c\u6211\u4eec\u79f0\u4e4b\u4e3a\u4fdd\u5b58\u73b0\u573a\u3002<\/p>\n

\u7136\u540e\u628aB\u4efb\u52a1\u7684\u6240\u6709\u5bc4\u5b58\u5668\u4ece\u5185\u5b58\u6062\u590d\u5230\u5bc4\u5b58\u5668\uff0c\u8fd9\u65f6\u5019\u5c31\u5df2\u7ecf\u5b8c\u6210\u4e00\u6b21\u4efb\u52a1\u5207\u6362\u4e86\u3002<\/p>\n

\u7136\u540e\u53c8\u8fc7\u4e86100ms\uff0c\u628aB\u4efb\u52a1\u4fdd\u5b58\u73b0\u573a\uff0c\u8f7d\u5165A\u4efb\u52a1\u7684\u5f53\u65f6\u6240\u6709\u5bc4\u5b58\u5668\u7684\u503c\uff0c\u4ece\u6b64\u5faa\u73af\u5f80\u590d\u3002<\/p>\n

\u7b80\u5355\u6765\u8bf4\uff0c\u4efb\u52a1\u5207\u6362\u5c31\u662f\u5207\u6362\u4e86\u4e00\u5806\u4efb\u52a1\u5bc4\u5b58\u5668\u3002<\/strong><\/p>\n

\u6709\u4eba\u53ef\u80fd\u89c9\u5f97\u597d\u5947\uff0c\u8fd9\u662f\u4e3a\u4ec0\u4e48\u5462\uff1f<\/p>\n

\u8fd9\u91cc\u6211\u4eec\u4e3e\u4e2a\u4f8b\u5b50:<\/p>\n

\u5047\u5982A\u4efb\u52a1\u7684\u6307\u4ee4\u5e8f\u5217\u662f:<\/p>\n

\u5730\u5740    \u6c47\u7f16\u6307\u4ee4\n0x100   mov eax, 1\n0x102   add eax, 2\n0x104   add eax, 3\n\neip = 0x100, eax = 0\n<\/code><\/pre>\n
B\u4efb\u52a1\u7684\u6307\u4ee4\u5e8f\u5217\u662f:<\/p>\n
\u5730\u5740    \u6c47\u7f16\u6307\u4ee4\n0x200   mov eax, 2\n0x202   add eax, 4\n0x204   add eax, 8\n\neip = 0x200, eax = 0\n<\/code><\/pre>\n
\n  eip = 0x100 \u4ee3\u8868\u4e0b\u4e00\u6761\u8fd0\u884c\u7684\u6307\u4ee4\u5c31\u662f0x100\u5730\u5740\u5904\u7684\u6307\u4ee4\n<\/p><\/blockquote>\n
\u4ee5\u4e0a\u9762\u7684\u60c5\u666f\u4e3a\u4f8b\uff0cA\u4efb\u52a1\u7684\u8d77\u59cbeip\u662f0x100<\/p>\n
\u7136\u540e\u6267\u884c\u4e86\u4e00\u6761\u6307\u4ee4,\u8fd9\u65f6A\u73b0\u573a:<\/p>\n
    eip = 0x102\n    eax = 1\n<\/code><\/pre>\n
\u6211\u4eec\u5047\u5982\u8fd9\u4e00\u6761\u6307\u4ee4\u6267\u884c\u4e86100ms\uff0c\u53d1\u751f\u4e86\u65f6\u949f\u4e2d\u65ad\uff0c\u8fd9\u4e2a\u65f6\u5019\u8fdb\u884c\u4e86\u4efb\u52a1\u5207\u6362\uff0c\u90a3\u4e48\u4f1a\u505a\u4ec0\u4e48\u5462\uff1f<\/p>\n
\u8fd9\u4e2a\u65f6\u5019\u5148\u628aA\u73b0\u573a\u4fdd\u5b58\uff0c\u7136\u540e\u628aB\u4efb\u52a1\u73b0\u573a\u7684\u5bc4\u5b58\u5668\uff0c\u5168\u90e8\u6062\u590d,\u8fd9\u65f6cpu\u5bc4\u5b58\u5668:<\/p>\n
    eip = 0x200\n    eax = 0\n<\/code><\/pre>\n
\u8fd9\u65f6\u5c31\u5207\u6362\u5230B\u7684\u4efb\u52a1\u4e2d\u4e86\u3002<\/p>\n
\u800ccpu\u6267\u884c\u6307\u4ee4\u53ea\u4f1a\u770beip\u5bc4\u5b58\u5668\u6307\u5411\u3002<\/p>\n
B\u4e5f\u6267\u884c\u4e86\u4e00\u6761\u6307\u4ee4\uff0c\u8fd9\u65f6:<\/p>\n
    eip = 0x202\n    eax = 2\n<\/code><\/pre>\n
\u5047\u5982\u8fd9\u6761\u6307\u4ee4\u82b1\u8d39\u4e86100ms\uff0c\u53c8\u8981\u5207\u6362\u56deA\u4efb\u52a1\u4e86,\u8fd9\u65f6\u5019\u4f1a\u628a\u521a\u521a\u4fdd\u5b58\u7684A\u73b0\u573a\u6062\u590d:<\/p>\n
    eip = 0x102\n    eax = 1\n<\/code><\/pre>\n
\u7136\u540eA\u6267\u884c\u4e86\u4e00\u6761\u6307\u4ee4\uff0c<\/p>\n
0x102   add eax, 2\n<\/code><\/pre>\n
\u7136\u540eeax\u4f1a\u53d8\u62103\uff0c\u5f53\u7136: \u5982\u679c\u6ca1\u6709\u4efb\u52a1\u5207\u6362\u7684\u8bdd\uff0ceip\u6267\u884c\u5230\u8fd9\u91cc\uff0ceax\u4e5f\u662f3<\/p>\n
\u4f60\u5c31\u4f1a\u60ca\u5947\u7684\u53d1\u73b0:<\/p>\n
\u6211\u4eec\u7684\u4efb\u52a1\u5207\u6362\u5e76\u6ca1\u6709\u5f71\u54cd\u5230\u5404\u81ea\u4efb\u52a1\u7684\u6267\u884c\u7ed3\u679c\uff0c\u5b83\u548c\u53ea\u8fd0\u884c\u5355\u4e2a\u4efb\u52a1\u8fd0\u884c\u662f\u4e00\u6837\u7684<\/strong><\/p>\n
\u5f53\u7136\uff0c\u6211\u4eec\u8fd9\u91cc\u53ea\u662f\u62ff\u4e24\u4e2a\u5bc4\u5b58\u5668\u6765\u8bf4\u660e\u539f\u7406\uff0c\u5176\u4ed6\u5bc4\u5b58\u5668\u4e5f\u662f\u5f88\u91cd\u8981\u7684\u3002<\/p>\n
\n
TSS\u786c\u4ef6\u8df3\u8f6c<\/h3>\n
\u4ec0\u4e48\u662fTSS\u5462:<\/p>\n
\n  TSS (Task State Segment) \u4efb\u52a1\u72b6\u6001\u6bb5\n<\/p><\/blockquote>\n
\u6682\u4e14\u628a\u5b83\u7406\u89e3\u6210\u4e00\u4e2a\u5305\u542b\u4e86\u5404\u79cd\u5bc4\u5b58\u5668\u7684\u7ed3\u6784\u4f53:<\/p>\n
struct TSS32\n{\n int backlink, esp0, ss0, esp1, ss1, esp2, ss2, cr3;\n int eip, eflags, eax, ecx, edx, ebx, esp, ebp, esi, edi;\n int es, cs, ss, ds, fs, gs;\n int ldtr, iomap;\n};\n<\/code><\/pre>\n
\u6bd4\u5982\u8bf4\u6211\u4eec\u8981\u81ea\u5df1\u5b9e\u73b0\u4efb\u52a1A\u73b0\u573a\u4fdd\u5b58\uff0c\u5e76\u4e14\u5207\u6362\u5230B\u4efb\u52a1\u3002<\/p>\n
\u6211\u4eec\u8981\u600e\u4e48\u505a\u5462\uff0c\u6211\u4eec\u9700\u8981\u628aA\u4efb\u52a1\u5404\u79cd\u5bc4\u5b58\u5668\u90fd\u624b\u52a8\u4fdd\u5b58\u5230\u5185\u5b58\uff0c\u7136\u540e\u628aB\u4efb\u52a1\u5bc4\u5b58\u5668\u90fd\u4ece\u5185\u5b58\u52a0\u8f7d\u5230\u5bc4\u5b58\u5668\u3002<\/p>\n
\u8fd9\u9700\u8981\u5199\u5f88\u591a\u6c47\u7f16\u6307\u4ee4\u3002<\/p>\n
\u7136\u540eintel\u63d0\u4f9b\u4e86\u4e00\u79cd\u57fa\u5740\uff0c\u8ba9\u4f60\u53ef\u4ee5\u201c\u4e00\u952e\u8df3\u8f6c\u201d\uff0c\u8fd9\u5c31\u662fTSS\u3002<\/p>\n
\n  \u4f7f\u7528TSS\u8df3\u8f6c\u662f\u5f88\u53e4\u8001\u7684\u4efb\u52a1\u5207\u6362\u673a\u5236\uff0c\u6bd4\u5982\u5728linux 0.11\u5185\u6838\u7248\u672c\u4e0a\u5c31\u662f\u4f7f\u7528TSS\uff0c\u73b0\u4ee3\u64cd\u4f5c\u7cfb\u7edf\u5df2\u7ecf\u4e0d\u518d\u4f7f\u7528\n<\/p><\/blockquote>\n
TSS\u8df3\u8f6c\u7684\u7ec6\u8282<\/h4>\n
\u5728\u4efb\u52a1\u5207\u6362\u7684\u8fc7\u7a0b\u4e2d\uff0c\u6bcf\u4e2a\u5904\u7406\u5668\u5bc4\u5b58\u5668\u7684\u503c\u4fdd\u5b58\u5230\u7531TR\u4efb\u52a1\u5bc4\u5b58\u5668\u6307\u5b9a\u7684TSS\u3002<\/p>\n
\u800c\u4efb\u52a1\u7684\u8df3\u8f6c\u5219\u7531\u4e00\u6761\u6c47\u7f16\u6307\u4ee4jmp far<\/strong>\u5b9e\u73b0<\/p>\n
\u4e0d\u8fc7\u5728\u6267\u884cfarjmp<\/strong>\u4e4b\u524d\u9700\u8981\u5728GDT\u91cc\u9996\u5148\u6ce8\u518c\u597dTSS\u7684\u5730\u5740\u3002<\/p>\n
\u8fd9\u6837\u5728farjmp<\/strong>\u4e4b\u540e\uff0cCPU\u4f1a\u81ea\u52a8\u4fdd\u5b58\u76f8\u5e94\u503c\u5230TSS\u91cc\u9762\uff0c\u7136\u540e\u8fd9\u4e2aTSS\u6240\u4fdd\u5b58\u7684\u5bc4\u5b58\u5668\u7684\u503c\u4f1a\u88ab\u53d6\u51fa\u8fd8\u539f\u5230\u5404\u4e2a\u5bc4\u5b58\u4e2d\u53bb\uff0c\u4ece\u800c\u5b9e\u73b0\u4e86\u4efb\u52a1\u73b0\u573a\u7684\u6062\u590d\uff0c\u5b9e\u73b0\u4e86\u4efb\u52a1\u7684\u8df3\u8f6c<\/p>\n
\u79d1\u666e\uff1a\u4ec0\u4e48\u662f\u8fdc\u8df3\u8f6c<\/h4>\n
\n  \u5f53\u7136\u7a0b\u5e8f\u7684\u8df3\u8f6c\u5206\u4e3a\u4e24\u79cd\u8df3\u8f6c<\/p>\n
  \u4e00\u79cd\u662fnear\u6a21\u5f0f\u8df3\u8f6c\u548cfar\u6a21\u5f0f\u8df3\u8f6c\u3002<\/p>\n
  \u4e00\u822c\u8df3\u8f6c\u7684\u5b9e\u73b0\u662f\u66f4\u6539EIP\u5bc4\u5b58\u5668\u7684\u503c\u6765\u5b9e\u73b0\uff0c<\/p>\n
  \u5728near\u6a21\u5f0f\u8df3\u8f6c\u4e2d\uff0c\u53ea\u662f\u6539\u5199EIP\u5bc4\u5b58\u5668\u7684\u503c<\/p>\n
  \u5728far\u6a21\u5f0f\u4e2d\u4e0d\u4ec5\u6539\u53d8EIP,\u800c\u4e14\u8fd8\u8981\u6539\u53d8CS\u5bc4\u5b58\u5668\u503c\u3002\n<\/p><\/blockquote>\n
\n
\u4efb\u52a1\u4f18\u5148\u7ea7\u8bbe\u5b9a<\/h3>\n
\u90a3\u4e48\u4e3a\u4ec0\u4e48\u9700\u8981\u4efb\u52a1\u4f18\u5148\u7ea7\u5462\uff1f<\/p>\n
\u4ee5\u4e0a\u9762\u7684\u4f8b\u5b50\u4e3a\u4f8b\uff0c\u6bcf\u4e2a\u4efb\u52a1\u90fd\u662f\u6267\u884c100ms\u7136\u540e\u5c31\u5f00\u59cb\u5207\u6362\u4efb\u52a1\u3002<\/p>\n
\u4f46\u662f\u6211\u8ba4\u4e3aA\u4efb\u52a1\u6bd4\u8f83\u91cd\u8981\uff0c\u9700\u8981\u7ed9200ms\u7684\u6267\u884c\u65f6\u95f4\uff0c\u7ed9B\u4efb\u52a1100ms\u65f6\u95f4\uff0c\u6211\u4eec\u8981\u600e\u4e48\u505a\u5462\uff1f<\/p>\n
\u5728\u73b0\u4ee3\u7684\u8ba1\u7b97\u673a\u64cd\u4f5c\u7cfb\u7edf\u4e2d\uff0c\u4efb\u52a1\u7684\u5207\u6362\u52a8\u4f5c\u57280.01-0.03\u79d2\u5de6\u53f3\u3002<\/p>\n
\u73b0\u4ee3\u7684\u64cd\u4f5c\u7cfb\u7edf\uff0c\u5bf9\u4efb\u52a1\u7684\u90fd\u53ef\u4ee5\u6709\u81ea\u5b9a\u4e49\u65f6\u95f4\u7247\u7684\u5206\u914d\u3002<\/p>\n
\u5373\u5728\u6267\u884c\u4e0d\u540c\u4efb\u52a1\u7684\u65f6\u5019\uff0c\u5206\u7ed9\u4efb\u52a1\u6267\u884c\u7684\u65f6\u95f4\u662f\u4e0d\u540c\u7684\u3002<\/p>\n
\u8bf4\u4e0b\u6211\u4eec\u7684\u5b9e\u73b0\uff0c\u4ecb\u7ecd\u4e0b\u4fdd\u5b58\u5355\u4e2a\u4efb\u52a1\u4fe1\u606f\u7684\u7ed3\u6784\u4f53:<\/p>\n
struct TASK\n{\n int sel, flags;\n int level;\n int priority;\n struct TSS32 tss;\n struct FIFO32 *fifo;\n};\n<\/code><\/pre>\n
\n  sel \u8be5\u4efb\u52a1\u7684\u6bb5\u9009\u62e9\u5b50(GDT\u4e2d\u7684\u9009\u62e9\u5b50)<\/p>\n
  flag \u6807\u8bc6\u8be5\u4efb\u52a1\u7684\u72b6\u6001<\/p>\n
  level \u4efb\u52a1\u8fd0\u884c\u8fd0\u884c\u5c42\u4e0a(\u8d8a\u4f4e\u5c42\u4f18\u5148\u8fd0\u884c)<\/p>\n
  priority: \u4f18\u5148\u7ea7(\u65f6\u95f4\u7247\u957f\u5ea6\uff0c\u8fd9\u91cc\u547d\u540d\u4e0d\u662f\u5f88\u597d\u3002\u3002)<\/p>\n
  tss: TSS\u6570\u636e\u7ed3\u6784<\/p>\n
  fifo \u8be5\u4efb\u52a1\u7f13\u51b2\u533a\n<\/p><\/blockquote>\n
\u5207\u6362\u5230\u6307\u5b9a\u4efb\u52a1\u4e4b\u524d\uff0c\u9996\u5148\u8bbe\u7f6eprioriy\u6307\u5b9a\u7684\u8d85\u65f6\u65f6\u95f4\u6bd4\u5982\u8bbe\u5b9a200ms\uff0c\u90a3\u5c31200ms\u540e\u624d\u53d1\u751f\u5207\u6362\u3002<\/p>\n
\u8d85\u65f6\u529f\u80fd\uff0c\u4e4b\u524d\u7684\u7ae0\u8282\u6709\u8bb2\u8ff0\u3002<\/p>\n
\u8fd9\u6837\u80fd\u505a\u5230\u4ec0\u4e48\u6548\u679c\u5462\uff1f<\/p>\n
\u6211\u4eec\u5c31\u5b9e\u73b0\u4e86\u4e24\u4e2a\u4efb\u52a1:
\nA\u548cB:<\/p>\n
void task_a()\n{\n    ...\n\n    int count = 0;\n    for (;;) \n    {\n        count++;    \n\n        \/\/ \u663e\u793a\u5230\u7a97\u4f53\n        print_count(count);\n    }\n}\n\nvoid task_b()\n{\n    ...\n\n    int count = 0;\n    for (;;) \n    {\n        count++;    \n\n        \/\/ \u663e\u793a\u5230\u7a97\u4f53\n        print_count(count);\n    }\n}\n<\/code><\/pre>\n
\u6211\u4eec\u8bbe\u5b9a\u4e86\u8fd9\u6837\u4e24\u4e2a\u4efb\u52a1\uff0c\u4efb\u52a1\u64cd\u4f5c\u662f\u4e00\u6837\u7684:\u90fd\u662f\u6267\u884c\u7d2f\u52a0\u64cd\u4f5c\u3002<\/p>\n
\u4f46\u662f\u6211\u4eec\u4efb\u52a1\u8bbe\u7f6e\u4e86\u4e0d\u540c\u7684\u65f6\u95f4\u7247\uff0cA\u4efb\u52a1\u8fd0\u884c10ms\u5c31\u5207\u6362\uff0c\u800cB\u4efb\u52a1\u8fd0\u884c20ms\u624d\u5207\u6362\u3002<\/p>\n
\u8fd0\u884c\u7ed3\u679c:<\/p>\n
\"image\"<\/p>\n
\u53ef\u4ee5\u770b\u5230B\u4efb\u52a1\u7684\u7d2f\u52a0\u6b21\u6570\u5927\u81f4\u662fA\u4efb\u52a1\u7684\u4e24\u500d\u3002<\/p>\n
\n
\u4efb\u52a1\u5206\u5c42<\/h3>\n
\u5f53\u7136\uff0c\u4ec5\u4ec5\u6709\u8bbe\u7f6e\u4efb\u52a1\u7684\u65f6\u95f4\u7247\u662f\u4e0d\u591f\u7684\u3002<\/p>\n
\u5728\u73b0\u5b9e\u4e2d\uff0c\u5f80\u5f80\u6709\u66f4\u7d27\u6025\u7684\u4efb\u52a1\u9700\u8981\u53bb\u6267\u884c\u3002<\/p>\n
\u6bd4\u5982\u540c\u65f6\u6709\u97f3\u4e50\u64ad\u653e\u4efb\u52a1<\/strong>\u548c\u7f51\u7edc\u63a5\u6536\u4efb\u52a1<\/strong>\u3002<\/p>\n
\u90a3\u4e48\u5728\u6709\u7f51\u7edc\u63a5\u6536\u4efb\u52a1\u7684\u65f6\u5019\uff0c\u5e94\u8be5\u4f18\u5148\u5904\u7406\u5b8c\u7f51\u7edc\u4efb\u52a1\uff0c\u518d\u5904\u7406\u97f3\u4e50\u64ad\u653e\u4efb\u52a1\u3002<\/p>\n
\u8fd9\u79cd\u4f18\u5148\u4e0d\u662f\u8bf4\u7ed9\u7f51\u7edc\u4efb\u52a1\u66f4\u591a\u7684\u65f6\u95f4\u7247\uff0c\u800c\u662f\u8bf4\u5728\u6709\u7f51\u7edc\u4efb\u52a1\u90fd\u4f1a\u4f18\u5148\u533a\u6267\u884c\u7f51\u7edc\u4efb\u52a1\uff0c\u7b49\u6267\u884c\u5230\u6ca1\u6709\u4e86\u7f51\u7edc\u8fd9\u79cd\u7d27\u6025\u7ea7\u522b\u7684\u4efb\u52a1\uff0c\u624d\u4f1a\u8003\u8651\u6267\u884c\u97f3\u4e50\u64ad\u653e\u7b49\u4e0d\u91cd\u8981\u4efb\u52a1\u3002<\/p>\n
\u56e0\u4e3a\u7f51\u7edc\u4efb\u52a1\u662f\u6bd4\u8f83\u91cd\u8981\u7684\uff0c\u5ef6\u65f6\u63a5\u6536\u662f\u53ef\u80fd\u5f15\u53d1\u534f\u8bae\u8d85\u65f6\u91cd\u4f20\u7684\u3002<\/p>\n
\u90a3\u4e48\u8fd9\u6837\u7684\u9700\u6c42\u4e0b\uff0c\u591a\u4efb\u52a1\u7684\u5206\u5c42\u7ba1\u7406\u7ed3\u6784\u5e94\u7528\u800c\u751f\u3002<\/p>\n
\u5728\u8fd9\u79cd\u67b6\u6784\u4e0b\uff0c\u5373\u4f7f\u4efb\u52a1\u7684\u65f6\u95f4\u7247\u76f8\u540c\uff0c\u4e5f\u4f1a\u6267\u884c\u5c42\u7ea7\u6700\u9ad8\u7684\u4efb\u52a1\uff0c\u7b49\u9ad8\u5c42\u4efb\u52a1\u6267\u884c\u5b8c\u6bd5\uff0c\u624d\u4f1a\u6267\u884c\u5e95\u5c42\u4efb\u52a1\u3002<\/p>\n
\u8fd9\u91cc\u6211\u4eec\u5f15\u5165\u4e86\u5c42\u7ea7\u7684\u6982\u5ff5\uff0c\u6bd4\u5982\u8bf4\u7f51\u7edc\u4efb\u52a1\u5c31\u662f\u9ad8\u5c42\u7684\u4efb\u52a1\uff0c\u97f3\u4e50\u64ad\u653e\u5c31\u662f\u5e95\u5c42\u4efb\u52a1\u3002<\/p>\n
\u6240\u4ee5\u8fd9\u91cc\u770b\u4e0b\u4efb\u52a1\u7ba1\u7406\u8868\u7684\u7ed3\u6784\u4f53:<\/p>\n
struct TASKLEVEL\n{\n int running;\n int now;\n struct TASK *tasks[MAX_TASKS_LV];\n};\n<\/code><\/pre>\n
\n  running: \u8be5\u5c42\u4e2d\u6709\u591a\u5c11\u4e2a\u4efb\u52a1\u5728\u8fd0\u884c<\/p>\n
  now: \u8be5\u5c42\u4e2d\u6b63\u5728\u8fd0\u884c\u7684\u662f\u54ea\u4e2a\u4efb\u52a1<\/p>\n
  tasks: TASK\u7684\u6307\u9488\u6570\u7ec4\n<\/p><\/blockquote>\n
struct TASKCTL\n{\n int now_lv;\n char lv_change;\n struct TASKLEVEL level[MAX_TASKLEVELS];\n struct TASK tasks0[MAX_TASKS];\n};\n<\/code><\/pre>\n
\n  now_lv: \u5f53\u524d\u4efb\u52a1\u8fd0\u884c\u5728\u54ea\u5c42\u4e0a\uff08lv==level\uff09<\/p>\n
  lv_change: \u4e0b\u6b21\u4efb\u52a1\u5207\u6362\u65f6,\u662f\u5426\u9700\u8981\u4fee\u6539level\n<\/p><\/blockquote>\n
\u4efb\u52a1\u5207\u6362\u6838\u5fc3\u64cd\u4f5c:<\/p>\n
\/\/\u4efb\u52a1\u5207\u6362\u51fd\u6570 \nvoid task_switch(void)\n{\n    \/\/\u5f53\u524d\u5c42\n    struct TASKLEVEL *tl = &taskctl->level[taskctl->now_lv];\n    struct TASK *new_task, *now_task = tl->tasks[tl->now];\n    tl->now++;\n\n    if (tl->now == tl->running)\n    {\n       tl->now = 0;\n    }\n    if (taskctl->lv_change != 0)\n    {  \n        \/\/\u5bfb\u627e\u6700\u4e0a\u5c42\u7684level\n        task_switchsub();      \n        \/\/\u66f4\u65b0tl\u8ba9\u5b83\u6307\u5411\u6700\u4e0a\u5c42\u7684level\n        tl = &taskctl->level[taskctl->now_lv];      \n    }\n\n    new_task = tl->tasks[tl->now];\n    timer_settime(task_timer, new_task->priority);\n\n    \/\/\u53ea\u6709\u4e00\u4e2a\u4efb\u52a1\u4e0d\u8df3\u8f6c\n    if (new_task != now_task)\n    {\n       farjmp(0, new_task->sel);\n    }\n    return;\n}\n<\/code><\/pre>\n
\n
\u4efb\u52a1\u7684\u4f11\u7720<\/h3>\n
\u5bf9\u5355\u4e2a\u4efb\u52a1\u7684\u4f11\u7720\u6682\u505c\u64cd\u4f5c\u5c31\u662f\uff0c\u4ece\u4efb\u52a1\u8868\u4e2d\u5220\u9664\uff0c\u4e0d\u53c2\u4e0e\u5185\u6838\u4efb\u52a1\u5207\u6362\u3002<\/p>\n
\/\/\u5220\u9664\u4efb\u52a1\nvoid task_remove(struct TASK *task)\n{\n    int i;\n    struct TASKLEVEL *tl = &taskctl->level[task->level];\n\n    \/\/\u5bfb\u5740task\u6240\u5728\u4f4d\u7f6e \n    for (i = 0; i < tl->running; i++)\n    {\n       if (tl->tasks[i] == task)\n       {\n           break;\n       }\n    }\n\n    tl->running--;\n    if (i < tl->now)\n    {\n       tl->now--; \n    }\n\n    if (tl->now >= tl->running)\n    {  \n       tl->now = 0;\n    }\n    \/\/\u4f11\u7720\u4e2d\n    task->flags = 1; \n\n    \/\/\u6574\u7406tasks\u6570\u7ec4 \n    for (; i < tl->running; i++)\n    {\n       tl->tasks[i] = tl->tasks[i + 1];\n    }\n\n    return;\n}\n<\/code><\/pre>\n
\n
\u5185\u6838\u4f11\u7720\u4efb\u52a1<\/h3>\n
\u5f88\u591a\u65f6\u5019\u8ba1\u7b97\u673a\u662f\u6ca1\u6709\u4efb\u4f55\u4efb\u52a1\u7684\uff0c\u4f46\u8ba1\u7b97\u673a\u603b\u8981\u6709\u4e2a\u4efb\u52a1\u5728\u6267\u884c,\u4e0d\u80fd\u8dd1\u98de\u4e86\u3002<\/p>\n
\u800c\u4e14\u8fd9\u4e2a\u4efb\u52a1\u4e0d\u80fd\u662f\u6b7b\u5faa\u73af\uff0c\u592a\u8d39\u7535\u3002<\/p>\n
\u6240\u4ee5intel\u51fa\u4e86\u4e86 HLT<\/strong> \u8fd9\u4e2a\u6c47\u7f16\u6307\u4ee4\u3002<\/p>\n
\n  \u6267\u884c\u8fd9\u6761\u6307\u4ee4\u540e\uff0c\u4f1a\u8ba9cpu\u8fdb\u5165\u4f11\u7720\u72b6\u6001\uff0c\u7b49\u5230\u6709\u4e2d\u65ad\u7684\u60c5\u51b5\u4e0b\u624d\u4f1a\u5524\u9192cpu\n<\/p><\/blockquote>\n
\u800c\u4e14\u57fa\u4e8e\u6211\u4eec\u7684\u4efb\u52a1\u5206\u5c42\u673a\u5236,\u6211\u4eec\u628a\u8fd9\u4e2a\u4efb\u52a1\u653e\u5230\u6700\u5e95\u5c42\u3002<\/p>\n
\u4e5f\u5c31\u662f\u6ca1\u6709\u5176\u4ed6\u4efb\u52a1\u7684\u65f6\u5019\uff0c\u624d\u4f1a\u6267\u884c\u8fd9\u4e2a\u4efb\u52a1\u3002<\/p>\n
\u5728\u73b0\u4ee3\u64cd\u4f5c\u7cfb\u7edf\u4e2d\u7684\uff0c\u6bd4\u5982windows \u4e2d\u7684System Idle Process(\u7cfb\u7edf\u7a7a\u95f2\u8fdb\u7a0b)\uff0c\u5927\u81f4\u5c31\u662f\u8fd9\u4e2a\u539f\u7406\u3002<\/p>\n
\u8fd8\u53ef\u4ee5\u57fa\u4e8e\u8fd9\u4e2a\uff0c\u7edf\u8ba1\u51fa\u8fd9\u4e2a\u4efb\u52a1\u7684\u5360\u7528\u65f6\u95f4\uff0c\u4ece\u800c\u8ba1\u7b97\u51fa\u73b0\u5728cpu\u7684\u5229\u7528\u7387\u3002<\/p>\n
\u6838\u5fc3\u4ee3\u7801\u5982\u4e0b:<\/p>\n
_io_hlt:            ;void io_hlt(void);\n    HLT\n    RET\n\n\/\/ \u95f2\u7f6e\u65f6\u4efb\u52a1\nvoid syshlt(void)\n{\n    for (;;) \n    {\n        io_hlt();\n    }\n}\n\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
\u64cd\u4f5c\u7cfb\u7edf\u662f\u5982\u4f55\u5b9e\u73b0\u4efb\u52a1\u5e76\u884c\u7684 \u8fd9\u91cc\u7684\u4efb\u52a1\u53ef\u4ee5\u7406\u89e3\u6210\u8fdb\u7a0b\u6216\u8005\u7ebf\u7a0b\u64cd\u4f5c \u4e0d\u77e5\u9053\u6709\u6ca1\u6709\u540c\u5b66\u5bf9\u6b64\u8868\u793a\u8fc7\u597d\u5947\uff0c\u591a\u4e2a\u8fdb\u7a0b\u5982 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"_links":{"self":[{"href":"http:\/\/www.sinkland.cn\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/www.sinkland.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.sinkland.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.sinkland.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.sinkland.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/www.sinkland.cn\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":195,"href":"http:\/\/www.sinkland.cn\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/195"}],"wp:attachment":[{"href":"http:\/\/www.sinkland.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.sinkland.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.sinkland.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}