{"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":287,"pdf_page":303,"physical_index":303,"physical_index_base":0,"printed_page_status":"recognized","page_sha256":"2423586956b47e81fc711c356e4ae1a4531c8e793e8530fcc35763f547735969"},"chapter":"编码隐匿在计算机软硬件背后的语言","content":"如果运算结果的最高位是1，那么符号标志位SF标志位置1，表示该计算结果是负数。\n\n如果运算结果为0，则零标志位ZF置0。\n\n如果运算结果中“1”的位数是偶数，即具有偶数性（evenparity)，则奇偶标志位PF置1；反之，如果“1”的位数是奇数，即运算结果具有奇数性（odd parity)，则PF置0。由于PF的这个特点，有时会被用来进行简单的错误检查。PF在8080程序中并不常用。\n\n进位标志位 CF的情况和第17章描述的稍有不同，当 ADD和ADC运算产生进位或者SUB和SBB 运算不发生借位时，CF 都置1。\n\n辅助进位标志位AF只有在运算结果的低4位向高4位有进位时才置1。它只用于DAA（Decimal Adjust Accumulator，十进制调整累加器）指令中。\n\n下面的两条指令会直接影响进位标志位 $\\mathbf { C F } _ { \\circ }$\n\n第17章设计的计算机可以执行 ADD、ADC、SUB和 SBB指令（虽然缺乏灵活性），而8080功能更为强大，它还可以执行AND（与）、OR（或）、XOR（异或）等逻辑运算。不论是算术运算还是逻辑运算，都是由8080处理器的算术逻辑单元（ALU）来完成的。\n\n以下是8080的算术运算和逻辑运算指令。\n\n19 两种典型的微处理器\n\n287","previous_page":286,"next_page":288}