{"resolved":true,"match_type":"uuid","source_type":"original_book","book_id":"38270854-596f-4a26-8183-db8c968c6020","title":"编码 隐匿在计算机软硬件背后的语言","author":null,"edition":null,"publisher":null,"year":null,"isbn":"9787121181184","requested_by":"printed_page","book":{"source_type":"original_book","book_id":"38270854-596f-4a26-8183-db8c968c6020","id":"38270854-596f-4a26-8183-db8c968c6020","uuid":"38270854-596f-4a26-8183-db8c968c6020","title":"编码 隐匿在计算机软硬件背后的语言","normalized_title":"编码隐匿在计算机软硬件背后的语言","author":null,"edition":null,"publisher":null,"year":null,"isbn":"9787121181184","isbns":["9787121181184","0123456789","6044921875","3039331000","0000000000","0000000000000"],"parsed":true,"ai_readable":true,"document_type":"book","page_count":438,"navigation_url":"https://workshop.closeclaw.top/ai/book/38270854-596f-4a26-8183-db8c968c6020","title_url":"https://workshop.closeclaw.top/ai/title/%E7%BC%96%E7%A0%81%20%E9%9A%90%E5%8C%BF%E5%9C%A8%E8%AE%A1%E7%AE%97%E6%9C%BA%E8%BD%AF%E7%A1%AC%E4%BB%B6%E8%83%8C%E5%90%8E%E7%9A%84%E8%AF%AD%E8%A8%80","fixed_page_url_template":"https://workshop.closeclaw.top/ai/book/38270854-596f-4a26-8183-db8c968c6020/page/{printed_page}","path_api_url_template":"https://workshop.closeclaw.top/api/ai/book/38270854-596f-4a26-8183-db8c968c6020/page/{printed_page}","read_url":"https://workshop.closeclaw.top/api/ai/read/38270854-596f-4a26-8183-db8c968c6020","page_url":"https://workshop.closeclaw.top/api/ai/books/38270854-596f-4a26-8183-db8c968c6020/page","search_url":"https://workshop.closeclaw.top/api/ai/books/38270854-596f-4a26-8183-db8c968c6020/search"},"page":{"printed_page":173,"pdf_page":189,"physical_index":189,"physical_index_base":0,"printed_page_status":"recognized","page_sha256":"84d3bfbd2b3a02dfb219e7ccb7af4a38524c42f4d65acc2f4a5a69dbf9020f80"},"chapter":"编码隐匿在计算机软硬件背后的语言","content":"在锁存器中保存多位值通常是很有用的。假如你想用第12章的加法器把3个8位数相加，可以在开关的第1行中存入第1个加数，以同样的方式把第2个加数存入第2行，但是必须记下第一次相加的结果。然后你需要把这个结果输入到开关的一行中，再把第3个加数输入到开关的另一行中。而你实际上不必输入中间结果，你应该能够在第一次计算之后直接使用它。\n\n可以使用锁存器来解决这个问题。我们在一个小盒子里布置8个锁存器，如前所述，每个锁存器包括两个或非门、两个与门以及一个反相器。所有的时钟输入端都互相连在一起。结果如下图所示。\n\n这个锁存器可以一次保存8位数。上面的8个输入端依次标记为 ${ \\bf D } _ { 0 } \\sim { \\bf D } _ { 7 }$ ，下面的8个输出端被标记为 $\\mathrm { Q } _ { 0 } \\sim \\mathrm { Q } _ { 7 }$ 。左边的输入是时钟（Clk)，时钟信号通常为 $\\mathbf { 0 } _ { \\circ }$ 当时钟信号为1时，D端输入的8位值被送到Q端输出。当时钟信号为0时，这8位值将保持不变，直到时钟信号再次被置1。\n\n也可以将8位锁存器的8个数据输入端和8个Q输出端画为两组线，如下图所示。\n\n下面是8位加法器的图示。\n\n14 反馈与触发器\n\n173","previous_page":172,"next_page":174}