"use strict"; const {Fragment: _Fragment, jsx: _jsx, jsxs: _jsxs} = arguments[0]; const {useMDXComponents: _provideComponents} = arguments[0]; function _createMdxContent(props) { const _components = { a: "a", code: "code", div: "div", h1: "h1", h2: "h2", h3: "h3", h4: "h4", img: "img", li: "li", ol: "ol", p: "p", path: "path", pre: "pre", span: "span", strong: "strong", svg: "svg", table: "table", tbody: "tbody", td: "td", th: "th", thead: "thead", tr: "tr", ul: "ul", ..._provideComponents(), ...props.components }; return _jsxs(_Fragment, { children: [_jsxs(_components.h1, { id: "段页式存储管理", children: [_jsx(_components.a, { className: "heading-link", href: "#段页式存储管理", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "段页式存储管理"] }), "\n", _jsxs(_components.h2, { id: "内存分页存储", children: [_jsx(_components.a, { className: "heading-link", href: "#内存分页存储", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "内存分页存储"] }), "\n", _jsxs(_components.h3, { id: "一级页表", children: [_jsx(_components.a, { className: "heading-link", href: "#一级页表", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "一级页表"] }), "\n", _jsx(_components.img, { src: "https://obsidian-contest-wesleyel.flowershow.me/attachment/3a49cf5eacb541d81f36b53365a882c5_MD5.png", alt: "attachment/3a49cf5eacb541d81f36b53365a882c5_MD5", className: "internal", "data-fs-resolved-file-path": "/attachment/3a49cf5eacb541d81f36b53365a882c5_MD5.png" }), "\n", _jsxs(_components.p, { children: ["本质上是将虚拟地址页号 ( ", _jsx(_components.code, { className: "language-auto", children: "vpn" }), ") 通过页表映射为物理页号 (", _jsx(_components.code, { className: "language-auto", children: "ppn" }), ") 的过程"] }), "\n", _jsx(_components.p, { children: "中间涉及" }), "\n", _jsxs(_components.ul, { children: ["\n", _jsxs(_components.li, { children: ["根据页面大小 (", _jsx(_components.code, { className: "language-auto", children: "PAGE_SIZE" }), ")，将虚拟地址 (", _jsx(_components.code, { className: "language-auto", children: "va" }), ") 拆分为虚拟地址页号 ( ", _jsx(_components.code, { className: "language-auto", children: "vpn" }), ") 和页内偏移 (", _jsx(_components.code, { className: "language-auto", children: "offset" }), ")，做法是算数位移"] }), "\n", _jsxs(_components.li, { children: ["根据页表起始地址（", _jsx(_components.code, { className: "language-auto", children: "page_table*" }), "）、数组元素长度 (", _jsx(_components.code, { className: "language-auto", children: "sizeof(uint32_t)" }), ") 和偏移量 (即虚拟地址页号 ( ", _jsx(_components.code, { className: "language-auto", children: "vpn" }), ") ) 得到物理页表的值 (", _jsx(_components.code, { className: "language-auto", children: "ppn" }), ")，做法是计算数组偏移量"] }), "\n", _jsxs(_components.li, { children: ["组装物理页表 (", _jsx(_components.code, { className: "language-auto", children: "ppn" }), ") 和页内偏移 (", _jsx(_components.code, { className: "language-auto", children: "offset" }), ")，获得物理地址 (", _jsx(_components.code, { className: "language-auto", children: "pa" }), ")"] }), "\n"] }), "\n", _jsx(_components.p, { children: "C 语言程序示例（加入了缺页和越界错误判断，以及预留 1 bit 用于判断页表是否有效）" }), "\n", _jsx(_components.pre, { className: "language-c", children: _jsxs(_components.code, { className: "language-c code-highlight", children: [_jsxs(_components.span, { className: "code-line", children: [_jsxs(_components.span, { className: "token macro property", children: [_jsx(_components.span, { className: "token directive-hash", children: "#" }), _jsx(_components.span, { className: "token directive keyword", children: "include" }), " ", _jsx(_components.span, { className: "token string", children: "" })] }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsxs(_components.span, { className: "token macro property", children: [_jsx(_components.span, { className: "token directive-hash", children: "#" }), _jsx(_components.span, { className: "token directive keyword", children: "include" }), " ", _jsx(_components.span, { className: "token string", children: "" })] }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsxs(_components.span, { className: "token macro property", children: [_jsx(_components.span, { className: "token directive-hash", children: "#" }), _jsx(_components.span, { className: "token directive keyword", children: "include" }), " ", _jsx(_components.span, { className: "token string", children: "" })] }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [_jsxs(_components.span, { className: "token macro property", children: [_jsx(_components.span, { className: "token directive-hash", children: "#" }), _jsx(_components.span, { className: "token directive keyword", children: "define" }), " ", _jsx(_components.span, { className: "token macro-name", children: "PAGE_SIZE" }), " ", _jsxs(_components.span, { className: "token expression", children: [_jsx(_components.span, { className: "token number", children: "4096U" }), " "] }), _jsx(_components.span, { className: "token comment", children: "// 4KB" })] }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsxs(_components.span, { className: "token macro property", children: [_jsx(_components.span, { className: "token directive-hash", children: "#" }), _jsx(_components.span, { className: "token directive keyword", children: "define" }), " ", _jsx(_components.span, { className: "token macro-name", children: "PAGE_OFFSET_BITS" }), " ", _jsxs(_components.span, { className: "token expression", children: [_jsx(_components.span, { className: "token number", children: "12U" }), " "] }), _jsx(_components.span, { className: "token comment", children: "// log2(PAGE_SIZE)" })] }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsxs(_components.span, { className: "token macro property", children: [_jsx(_components.span, { className: "token directive-hash", children: "#" }), _jsx(_components.span, { className: "token directive keyword", children: "define" }), " ", _jsx(_components.span, { className: "token macro-name", children: "PAGE_TABLE_ENTRIES" }), " ", _jsxs(_components.span, { className: "token expression", children: [_jsx(_components.span, { className: "token number", children: "1024U" }), " "] }), _jsx(_components.span, { className: "token comment", children: "// 示例：支持 1024 个虚拟页" })] }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsxs(_components.span, { className: "token macro property", children: [_jsx(_components.span, { className: "token directive-hash", children: "#" }), _jsx(_components.span, { className: "token directive keyword", children: "define" }), " ", _jsx(_components.span, { className: "token macro-name", children: "INVALID_PTE" }), " ", _jsxs(_components.span, { className: "token expression", children: [_jsx(_components.span, { className: "token number", children: "0U" }), " "] }), _jsx(_components.span, { className: "token comment", children: "// 表示无效的页表项" })] }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token comment", children: "// 页表：每个条目为一个 32 位无符号数" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token comment", children: "// bit0: valid (1 = 映射有效；0 = 无效/未映射)" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token comment", children: "// bit31..1: 物理页号 (PPN)" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token keyword", children: "static" }), " ", _jsx(_components.span, { className: "token class-name", children: "uint32_t" }), " page_table", _jsx(_components.span, { className: "token punctuation", children: "[" }), "PAGE_TABLE_ENTRIES", _jsx(_components.span, { className: "token punctuation", children: "]" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsx(_components.span, { className: "code-line", children: _jsx(_components.span, { className: "token comment", children: "/**\n" }) }), _jsx(_components.span, { className: "code-line", children: _jsx(_components.span, { className: "token comment", children: " * 初始化指定虚拟页号 vpn 到物理页号 ppn 的映射，\n" }) }), _jsx(_components.span, { className: "code-line", children: _jsx(_components.span, { className: "token comment", children: " * 并将其标记为有效。\n" }) }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token comment", children: " */" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token keyword", children: "void" }), " ", _jsx(_components.span, { className: "token function", children: "map_page" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token class-name", children: "uint32_t" }), " vpn", _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token class-name", children: "uint32_t" }), " ppn", _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "if" }), " ", _jsx(_components.span, { className: "token punctuation", children: "(" }), "vpn ", _jsx(_components.span, { className: "token operator", children: ">=" }), " PAGE_TABLE_ENTRIES", _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token function", children: "fprintf" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token constant", children: "stderr" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token string", children: "\"Error: vpn out of range\\n\"" }), _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token function", children: "exit" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token number", children: "1" }), _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "}" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token comment", children: "// 物理页号左移 1 位，高 31 位存 PPN；最低位设为 1（valid）" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" page_table", _jsx(_components.span, { className: "token punctuation", children: "[" }), "vpn", _jsx(_components.span, { className: "token punctuation", children: "]" }), " ", _jsx(_components.span, { className: "token operator", children: "=" }), " ", _jsx(_components.span, { className: "token punctuation", children: "(" }), "ppn ", _jsx(_components.span, { className: "token operator", children: "<<" }), " ", _jsx(_components.span, { className: "token number", children: "1" }), _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token operator", children: "|" }), " ", _jsx(_components.span, { className: "token number", children: "1U" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token punctuation", children: "}" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsx(_components.span, { className: "code-line", children: _jsx(_components.span, { className: "token comment", children: "/**\n" }) }), _jsx(_components.span, { className: "code-line", children: _jsx(_components.span, { className: "token comment", children: " * 将虚拟地址 va 翻译为物理地址，若发生缺页则返回 INVALID_PTE。\n" }) }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token comment", children: " */" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token class-name", children: "uint32_t" }), " ", _jsx(_components.span, { className: "token function", children: "translate_va_to_pa" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token class-name", children: "uint32_t" }), " va", _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token comment", children: "// 1) 拆分：页号和页内偏移" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token class-name", children: "uint32_t" }), " vpn ", _jsx(_components.span, { className: "token operator", children: "=" }), " va ", _jsx(_components.span, { className: "token operator", children: ">>" }), " PAGE_OFFSET_BITS", _jsx(_components.span, { className: "token punctuation", children: ";" }), " ", _jsx(_components.span, { className: "token comment", children: "// 虚拟页号" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token class-name", children: "uint32_t" }), " offset ", _jsx(_components.span, { className: "token operator", children: "=" }), " va ", _jsx(_components.span, { className: "token operator", children: "&" }), " ", _jsx(_components.span, { className: "token punctuation", children: "(" }), "PAGE_SIZE ", _jsx(_components.span, { className: "token operator", children: "-" }), " ", _jsx(_components.span, { className: "token number", children: "1U" }), _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), " ", _jsx(_components.span, { className: "token comment", children: "// 页内偏移" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "if" }), " ", _jsx(_components.span, { className: "token punctuation", children: "(" }), "vpn ", _jsx(_components.span, { className: "token operator", children: ">=" }), " PAGE_TABLE_ENTRIES", _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token comment", children: "// 虚拟地址超出支持范围" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "return" }), " INVALID_PTE", _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "}" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token comment", children: "// 2) 取出页表项" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token class-name", children: "uint32_t" }), " pte ", _jsx(_components.span, { className: "token operator", children: "=" }), " page_table", _jsx(_components.span, { className: "token punctuation", children: "[" }), "vpn", _jsx(_components.span, { className: "token punctuation", children: "]" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "if" }), " ", _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), "pte ", _jsx(_components.span, { className: "token operator", children: "&" }), " ", _jsx(_components.span, { className: "token number", children: "1U" }), _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token operator", children: "==" }), " ", _jsx(_components.span, { className: "token number", children: "0" }), _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token comment", children: "// valid 位为 0，视为缺页（Page Fault）" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "return" }), " INVALID_PTE", _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "}" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token comment", children: "// 3) 提取物理页号" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token class-name", children: "uint32_t" }), " ppn ", _jsx(_components.span, { className: "token operator", children: "=" }), " pte ", _jsx(_components.span, { className: "token operator", children: ">>" }), " ", _jsx(_components.span, { className: "token number", children: "1" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token comment", children: "// 4) 合成物理地址" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "return" }), " ", _jsx(_components.span, { className: "token punctuation", children: "(" }), "ppn ", _jsx(_components.span, { className: "token operator", children: "<<" }), " PAGE_OFFSET_BITS", _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token operator", children: "|" }), " offset", _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token punctuation", children: "}" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token keyword", children: "int" }), " ", _jsx(_components.span, { className: "token function", children: "main" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token keyword", children: "void" }), _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token comment", children: "// 示例：将虚拟页 1 映射到物理页 0x10" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token function", children: "map_page" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token number", children: "1" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token number", children: "0x10" }), _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token comment", children: "// 测试几组虚拟地址" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token class-name", children: "uint32_t" }), " test_vas", _jsx(_components.span, { className: "token punctuation", children: "[" }), _jsx(_components.span, { className: "token punctuation", children: "]" }), " ", _jsx(_components.span, { className: "token operator", children: "=" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token number", children: "0x00000000" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token comment", children: "// VPN=0, offset=0" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token number", children: "0x00001000" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token comment", children: "// VPN=1, offset=0" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token number", children: "0x00001ABC" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token comment", children: "// VPN=1, offset=0xABC" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token number", children: "0x00400000" }), " ", _jsx(_components.span, { className: "token comment", children: "// VPN=1024, 越界" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "}" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "for" }), " ", _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token class-name", children: "size_t" }), " i ", _jsx(_components.span, { className: "token operator", children: "=" }), " ", _jsx(_components.span, { className: "token number", children: "0" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), " i ", _jsx(_components.span, { className: "token operator", children: "<" }), " ", _jsx(_components.span, { className: "token keyword", children: "sizeof" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), "test_vas", _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token operator", children: "/" }), _jsx(_components.span, { className: "token keyword", children: "sizeof" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), "test_vas", _jsx(_components.span, { className: "token punctuation", children: "[" }), _jsx(_components.span, { className: "token number", children: "0" }), _jsx(_components.span, { className: "token punctuation", children: "]" }), _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), " i", _jsx(_components.span, { className: "token operator", children: "++" }), _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token class-name", children: "uint32_t" }), " va ", _jsx(_components.span, { className: "token operator", children: "=" }), " test_vas", _jsx(_components.span, { className: "token punctuation", children: "[" }), "i", _jsx(_components.span, { className: "token punctuation", children: "]" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token class-name", children: "uint32_t" }), " pa ", _jsx(_components.span, { className: "token operator", children: "=" }), " ", _jsx(_components.span, { className: "token function", children: "translate_va_to_pa" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), "va", _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "if" }), " ", _jsx(_components.span, { className: "token punctuation", children: "(" }), "pa ", _jsx(_components.span, { className: "token operator", children: "==" }), " INVALID_PTE", _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token function", children: "printf" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token string", children: "\"VA 0x%08X → Page Fault / Invalid mapping\\n\"" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " va", _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "}" }), " ", _jsx(_components.span, { className: "token keyword", children: "else" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token function", children: "printf" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token string", children: "\"VA 0x%08X → PA 0x%08X\\n\"" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " va", _jsx(_components.span, { className: "token punctuation", children: "," }), " pa", _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "}" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "}" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "return" }), " ", _jsx(_components.span, { className: "token number", children: "0" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token punctuation", children: "}" }), "\n"] })] }) }), "\n", _jsxs(_components.h2, { id: "二级页表", children: [_jsx(_components.a, { className: "heading-link", href: "#二级页表", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "二级页表"] }), "\n", _jsx(_components.img, { src: "https://obsidian-contest-wesleyel.flowershow.me/attachment/10fe3c71680edef0b88059298e508725_MD5.png", alt: "attachment/10fe3c71680edef0b88059298e508725_MD5", className: "internal", "data-fs-resolved-file-path": "/attachment/10fe3c71680edef0b88059298e508725_MD5.png" }), "\n", _jsxs(_components.h3, { id: "二级页表地址变换流程", children: [_jsx(_components.a, { className: "heading-link", href: "#二级页表地址变换流程", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "二级页表地址变换流程"] }), "\n", _jsxs(_components.ol, { children: ["\n", _jsxs(_components.li, { children: ["\n", _jsx(_components.p, { children: _jsx(_components.strong, { children: "虚拟地址拆分" }) }), "\n", _jsx(_components.pre, { className: "language-plaintext", children: _jsx(_components.code, { className: "language-plaintext code-highlight", children: _jsx(_components.span, { className: "code-line", children: "| 一级页号 (P1) | 二级页号 (P2) | 页内偏移 (Offset) |\n" }) }) }), "\n", _jsxs(_components.ul, { children: ["\n", _jsx(_components.li, { children: "通过虚拟地址位数和页大小自动划分（如 32 位系统 +4KB 页时：P1=10bit, P2=10bit, Offset=12bit）" }), "\n"] }), "\n"] }), "\n", _jsxs(_components.li, { children: ["\n", _jsx(_components.p, { children: _jsx(_components.strong, { children: "一级页表查询" }) }), "\n", _jsxs(_components.ul, { children: ["\n", _jsxs(_components.li, { children: ["通过 ", _jsx(_components.code, { className: "language-auto", children: "页目录基址寄存器" }), "（CR3）找到页目录表"] }), "\n", _jsxs(_components.li, { children: ["用 ", _jsx(_components.code, { className: "language-auto", children: "P1" }), " 作为索引定位页目录项（PDE）"] }), "\n", _jsx(_components.li, { children: "检查 PDE 的有效位（若无效触发缺页异常）" }), "\n"] }), "\n"] }), "\n", _jsxs(_components.li, { children: ["\n", _jsx(_components.p, { children: _jsx(_components.strong, { children: "二级页表查询" }) }), "\n", _jsxs(_components.ul, { children: ["\n", _jsx(_components.li, { children: "从 PDE 中获取二级页表物理基址" }), "\n", _jsxs(_components.li, { children: ["用 ", _jsx(_components.code, { className: "language-auto", children: "P2" }), " 作为索引定位页表项（PTE）"] }), "\n", _jsx(_components.li, { children: "检查 PTE 的有效位（若无效触发缺页异常）" }), "\n"] }), "\n"] }), "\n", _jsxs(_components.li, { children: ["\n", _jsx(_components.p, { children: _jsx(_components.strong, { children: "物理地址合成" }) }), "\n", _jsx(_components.pre, { className: "language-plaintext", children: _jsx(_components.code, { className: "language-plaintext code-highlight", children: _jsx(_components.span, { className: "code-line", children: "物理地址 = (PTE中的物理页框号 << Offset位数) | Offset\n" }) }) }), "\n"] }), "\n"] }), "\n", _jsxs(_components.h3, { id: "硬件辅助机制", children: [_jsx(_components.a, { className: "heading-link", href: "#硬件辅助机制", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "硬件辅助机制"] }), "\n", _jsxs(_components.ul, { children: ["\n", _jsxs(_components.li, { children: [_jsx(_components.strong, { children: "TLB 加速" }), "：缓存最近使用的页表项"] }), "\n", _jsxs(_components.li, { children: [_jsx(_components.strong, { children: "缺页处理" }), "：当 PTE 无效时触发异常，由 OS 加载缺失页"] }), "\n", _jsxs(_components.li, { children: [_jsx(_components.strong, { children: "权限检查" }), "：同时验证 PTE 中的 RWX 权限位"] }), "\n"] }), "\n", _jsxs(_components.h3, { id: "对比单级页表", children: [_jsx(_components.a, { className: "heading-link", href: "#对比单级页表", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "对比单级页表"] }), "\n", _jsx(_components.div, { className: "overflow-x-auto", children: _jsxs(_components.table, { children: [_jsx(_components.thead, { children: _jsxs(_components.tr, { children: [_jsx(_components.th, { children: "特性" }), _jsx(_components.th, { children: "单级页表" }), _jsx(_components.th, { children: "二级页表" })] }) }), _jsxs(_components.tbody, { children: [_jsxs(_components.tr, { children: [_jsx(_components.td, { children: "空间占用" }), _jsx(_components.td, { children: "连续大空间（4MB）" }), _jsx(_components.td, { children: "离散小空间（按需分配）" })] }), _jsxs(_components.tr, { children: [_jsx(_components.td, { children: "查询速度" }), _jsx(_components.td, { children: "一次访存" }), _jsx(_components.td, { children: "两次访存（可被 TLB 优化）" })] }), _jsxs(_components.tr, { children: [_jsx(_components.td, { children: "适用场景" }), _jsx(_components.td, { children: "小地址空间系统" }), _jsx(_components.td, { children: "32/64 位现代系统" })] })] })] }) }), "\n", _jsxs(_components.h2, { id: "分段式存储管理", children: [_jsx(_components.a, { className: "heading-link", href: "#分段式存储管理", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "分段式存储管理"] }), "\n", _jsx(_components.img, { src: "https://obsidian-contest-wesleyel.flowershow.me/attachment/52081a3529aaabcb50feb05c94916650_MD5.png", alt: "attachment/52081a3529aaabcb50feb05c94916650_MD5", className: "internal", "data-fs-resolved-file-path": "/attachment/52081a3529aaabcb50feb05c94916650_MD5.png" }), "\n", _jsxs(_components.ul, { children: ["\n", _jsxs(_components.li, { children: ["给定一个逻辑地址 ", _jsx(_components.code, { className: "language-auto", children: "A" }), "，其由段号 ", _jsx(_components.code, { className: "language-auto", children: "S" }), " 和段内偏移 ", _jsx(_components.code, { className: "language-auto", children: "W" }), " 组成。"] }), "\n", _jsxs(_components.li, { children: ["段表中包含每个段的 ", _jsx(_components.strong, { children: "基址（Base）" }), " 和 ", _jsx(_components.strong, { children: "段长（Limit）" }), "。"] }), "\n", _jsxs(_components.li, { children: ["转换过程：", "\n", _jsxs(_components.ol, { children: ["\n", _jsxs(_components.li, { children: ["取出段号 ", _jsx(_components.code, { className: "language-auto", children: "S" }), " 对应的段表项。"] }), "\n", _jsxs(_components.li, { children: ["检查 ", _jsx(_components.code, { className: "language-auto", children: "W" }), " 是否小于该段的段长 ", _jsx(_components.code, { className: "language-auto", children: "M" }), "（越界检查）。"] }), "\n", _jsx(_components.li, { children: "检查段表项中的段长 C 是否大于偏移量 W。" }), "\n", _jsxs(_components.li, { children: ["如果不越界，则物理地址 ", _jsx(_components.code, { className: "language-auto", children: "E = 基址 + 偏移量" }), "。"] }), "\n"] }), "\n"] }), "\n"] }), "\n", _jsx(_components.pre, { className: "language-c", children: _jsxs(_components.code, { className: "language-c code-highlight", children: [_jsxs(_components.span, { className: "code-line", children: [_jsxs(_components.span, { className: "token macro property", children: [_jsx(_components.span, { className: "token directive-hash", children: "#" }), _jsx(_components.span, { className: "token directive keyword", children: "include" }), " ", _jsx(_components.span, { className: "token string", children: "" })] }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [_jsxs(_components.span, { className: "token macro property", children: [_jsx(_components.span, { className: "token directive-hash", children: "#" }), _jsx(_components.span, { className: "token directive keyword", children: "define" }), " ", _jsx(_components.span, { className: "token macro-name", children: "NUM_SEGMENTS" }), " ", _jsx(_components.span, { className: "token expression", children: _jsx(_components.span, { className: "token number", children: "4" }) })] }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token keyword", children: "typedef" }), " ", _jsx(_components.span, { className: "token keyword", children: "struct" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "int" }), " limit", _jsx(_components.span, { className: "token punctuation", children: ";" }), " ", _jsx(_components.span, { className: "token comment", children: "// 段长" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "int" }), " base", _jsx(_components.span, { className: "token punctuation", children: ";" }), " ", _jsx(_components.span, { className: "token comment", children: "// 段基址" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token punctuation", children: "}" }), " SegmentDescriptor", _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token comment", children: "// 模拟段表" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: ["SegmentDescriptor segment_table", _jsx(_components.span, { className: "token punctuation", children: "[" }), "NUM_SEGMENTS", _jsx(_components.span, { className: "token punctuation", children: "]" }), " ", _jsx(_components.span, { className: "token operator", children: "=" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "{" }), _jsx(_components.span, { className: "token number", children: "1024" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token number", children: "6144" }), _jsx(_components.span, { className: "token punctuation", children: "}" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token comment", children: "// 段0: 1KB, 基址6KB" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "{" }), _jsx(_components.span, { className: "token number", children: "600" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token number", children: "4096" }), _jsx(_components.span, { className: "token punctuation", children: "}" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token comment", children: "// 段1: 600B, 基址4KB" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "{" }), _jsx(_components.span, { className: "token number", children: "500" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token number", children: "8192" }), _jsx(_components.span, { className: "token punctuation", children: "}" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token comment", children: "// 段2: 500B, 基址8KB" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "{" }), _jsx(_components.span, { className: "token number", children: "200" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token number", children: "9200" }), _jsx(_components.span, { className: "token punctuation", children: "}" }), " ", _jsx(_components.span, { className: "token comment", children: "// 段3: 200B, 基址9200" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token punctuation", children: "}" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token comment", children: "// 逻辑地址结构：段号 + 段内偏移" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token keyword", children: "typedef" }), " ", _jsx(_components.span, { className: "token keyword", children: "struct" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "int" }), " segment", _jsx(_components.span, { className: "token punctuation", children: ";" }), " ", _jsx(_components.span, { className: "token comment", children: "// 段号S" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "int" }), " offset", _jsx(_components.span, { className: "token punctuation", children: ";" }), " ", _jsx(_components.span, { className: "token comment", children: "// 段内偏移W" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token punctuation", children: "}" }), " LogicalAddress", _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token comment", children: "// 地址转换函数" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token keyword", children: "int" }), " ", _jsx(_components.span, { className: "token function", children: "logical_to_physical" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), "LogicalAddress la", _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "if" }), " ", _jsx(_components.span, { className: "token punctuation", children: "(" }), "la", _jsx(_components.span, { className: "token punctuation", children: "." }), "segment ", _jsx(_components.span, { className: "token operator", children: "<" }), " ", _jsx(_components.span, { className: "token number", children: "0" }), " ", _jsx(_components.span, { className: "token operator", children: "||" }), " la", _jsx(_components.span, { className: "token punctuation", children: "." }), "segment ", _jsx(_components.span, { className: "token operator", children: ">=" }), " NUM_SEGMENTS", _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token function", children: "printf" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token string", children: "\"错误：无效的段号 %d\\n\"" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " la", _jsx(_components.span, { className: "token punctuation", children: "." }), "segment", _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "return" }), " ", _jsx(_components.span, { className: "token operator", children: "-" }), _jsx(_components.span, { className: "token number", children: "1" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "}" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [" SegmentDescriptor sd ", _jsx(_components.span, { className: "token operator", children: "=" }), " segment_table", _jsx(_components.span, { className: "token punctuation", children: "[" }), "la", _jsx(_components.span, { className: "token punctuation", children: "." }), "segment", _jsx(_components.span, { className: "token punctuation", children: "]" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "if" }), " ", _jsx(_components.span, { className: "token punctuation", children: "(" }), "la", _jsx(_components.span, { className: "token punctuation", children: "." }), "offset ", _jsx(_components.span, { className: "token operator", children: ">=" }), " sd", _jsx(_components.span, { className: "token punctuation", children: "." }), "limit", _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token function", children: "printf" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token string", children: "\"错误：段内偏移越界，offset = %d, limit = %d\\n\"" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " la", _jsx(_components.span, { className: "token punctuation", children: "." }), "offset", _jsx(_components.span, { className: "token punctuation", children: "," }), " sd", _jsx(_components.span, { className: "token punctuation", children: "." }), "limit", _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "return" }), " ", _jsx(_components.span, { className: "token operator", children: "-" }), _jsx(_components.span, { className: "token number", children: "1" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token punctuation", children: "}" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "int" }), " physical_address ", _jsx(_components.span, { className: "token operator", children: "=" }), " sd", _jsx(_components.span, { className: "token punctuation", children: "." }), "base ", _jsx(_components.span, { className: "token operator", children: "+" }), " la", _jsx(_components.span, { className: "token punctuation", children: "." }), "offset", _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token function", children: "printf" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token string", children: "\"逻辑地址 (段号: %d, 偏移: %d) => 物理地址: %d\\n\"" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " la", _jsx(_components.span, { className: "token punctuation", children: "." }), "segment", _jsx(_components.span, { className: "token punctuation", children: "," }), " la", _jsx(_components.span, { className: "token punctuation", children: "." }), "offset", _jsx(_components.span, { className: "token punctuation", children: "," }), " physical_address", _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "return" }), " physical_address", _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token punctuation", children: "}" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token keyword", children: "int" }), " ", _jsx(_components.span, { className: "token function", children: "main" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), _jsx(_components.span, { className: "token punctuation", children: ")" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" LogicalAddress la ", _jsx(_components.span, { className: "token operator", children: "=" }), " ", _jsx(_components.span, { className: "token punctuation", children: "{" }), _jsx(_components.span, { className: "token number", children: "2" }), _jsx(_components.span, { className: "token punctuation", children: "," }), " ", _jsx(_components.span, { className: "token number", children: "100" }), _jsx(_components.span, { className: "token punctuation", children: "}" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), " ", _jsx(_components.span, { className: "token comment", children: "// 图中的示例：段号2，偏移100" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token function", children: "logical_to_physical" }), _jsx(_components.span, { className: "token punctuation", children: "(" }), "la", _jsx(_components.span, { className: "token punctuation", children: ")" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [" ", _jsx(_components.span, { className: "token keyword", children: "return" }), " ", _jsx(_components.span, { className: "token number", children: "0" }), _jsx(_components.span, { className: "token punctuation", children: ";" }), "\n"] }), _jsxs(_components.span, { className: "code-line", children: [_jsx(_components.span, { className: "token punctuation", children: "}" }), "\n"] }), _jsx(_components.span, { className: "code-line", children: "\n" })] }) }), "\n", _jsxs(_components.h2, { id: "优缺点及对比", children: [_jsx(_components.a, { className: "heading-link", href: "#优缺点及对比", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "优缺点及对比"] }), "\n", _jsxs(_components.h3, { id: "一表项存储位置与进程对应关系", children: [_jsx(_components.a, { className: "heading-link", href: "#一表项存储位置与进程对应关系", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "一、表项存储位置与进程对应关系"] }), "\n", _jsx(_components.div, { className: "overflow-x-auto", children: _jsxs(_components.table, { children: [_jsx(_components.thead, { children: _jsxs(_components.tr, { children: [_jsx(_components.th, { children: "表项类型" }), _jsx(_components.th, { children: "存储位置" }), _jsx(_components.th, { children: "进程对应关系" })] }) }), _jsxs(_components.tbody, { children: [_jsxs(_components.tr, { children: [_jsx(_components.td, { children: _jsx(_components.strong, { children: "页表项 (PTE)" }) }), _jsx(_components.td, { children: "存放在内存的页表中（多级页表时分散存储）" }), _jsxs(_components.td, { children: ["每个进程有", _jsx(_components.strong, { children: "独立的页目录和页表" }), "，表项数量=虚拟地址空间大小/页大小"] })] }), _jsxs(_components.tr, { children: [_jsx(_components.td, { children: _jsx(_components.strong, { children: "段表项" }) }), _jsx(_components.td, { children: "存放在内核空间的段表中" }), _jsxs(_components.td, { children: ["每个进程有", _jsx(_components.strong, { children: "独立的段表" }), "，表项数量=进程拥有的段数量（通常 4-16 个）"] })] })] })] }) }), "\n", _jsxs(_components.h3, { id: "二分页与分段的核心对比", children: [_jsx(_components.a, { className: "heading-link", href: "#二分页与分段的核心对比", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "二、分页与分段的核心对比"] }), "\n", _jsxs(_components.h4, { id: "1-分页机制paging", children: [_jsx(_components.a, { className: "heading-link", href: "#1-分页机制paging", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "1. 分页机制（Paging）"] }), "\n", _jsx(_components.p, { children: _jsx(_components.strong, { children: "✅ 优点" }) }), "\n", _jsxs(_components.ul, { children: ["\n", _jsx(_components.li, { children: "内存利用率高：消除外部碎片，按固定大小分配" }), "\n", _jsx(_components.li, { children: "透明性：对程序员不可见，由 OS 和硬件管理" }), "\n", _jsx(_components.li, { children: "支持虚拟内存：缺页中断实现按需调页" }), "\n", _jsx(_components.li, { children: "适合大地址空间：多级页表节省内存" }), "\n"] }), "\n", _jsx(_components.p, { children: _jsx(_components.strong, { children: "❌ 缺点" }) }), "\n", _jsxs(_components.ul, { children: ["\n", _jsx(_components.li, { children: "存在内部碎片（平均半页浪费）" }), "\n", _jsx(_components.li, { children: "共享困难：需保持各进程页表同步" }), "\n", _jsx(_components.li, { children: "无逻辑保护：单页可能包含混合类型数据" }), "\n"] }), "\n", _jsxs(_components.h4, { id: "2-分段机制segmentation", children: [_jsx(_components.a, { className: "heading-link", href: "#2-分段机制segmentation", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "2. 分段机制（Segmentation）"] }), "\n", _jsx(_components.p, { children: _jsx(_components.strong, { children: "✅ 优点" }) }), "\n", _jsxs(_components.ul, { children: ["\n", _jsx(_components.li, { children: "逻辑性强：按程序自然结构（代码/数据/堆栈）划分" }), "\n", _jsx(_components.li, { children: "易于共享：以段为单位设置权限" }), "\n", _jsx(_components.li, { children: "动态扩展：段长度可动态增长" }), "\n", _jsx(_components.li, { children: "安全保护：段边界检查防止越界访问" }), "\n"] }), "\n", _jsx(_components.p, { children: _jsx(_components.strong, { children: "❌ 缺点" }) }), "\n", _jsxs(_components.ul, { children: ["\n", _jsx(_components.li, { children: "产生外部碎片：需配合紧凑技术" }), "\n", _jsx(_components.li, { children: "内存管理复杂：需维护可变大小的内存块" }), "\n", _jsx(_components.li, { children: "不适合大地址空间：段表会变得庞大" }), "\n"] }), "\n", _jsxs(_components.h3, { id: "三现代系统的典型实现", children: [_jsx(_components.a, { className: "heading-link", href: "#三现代系统的典型实现", children: _jsx(_components.svg, { xmlns: "http:www.w3.org/2000/svg", fill: "#ab2b65", viewBox: "0 0 20 20", className: "w-5 h-5", children: _jsx(_components.path, { fillRule: "evenodd", clipRule: "evenodd", d: "M9.493 2.853a.75.75 0 00-1.486-.205L7.545 6H4.198a.75.75 0 000 1.5h3.14l-.69 5H3.302a.75.75 0 000 1.5h3.14l-.435 3.148a.75.75 0 001.486.205L7.955 14h2.986l-.434 3.148a.75.75 0 001.486.205L12.456 14h3.346a.75.75 0 000-1.5h-3.14l.69-5h3.346a.75.75 0 000-1.5h-3.14l.435-3.147a.75.75 0 00-1.486-.205L12.045 6H9.059l.434-3.147zM8.852 7.5l-.69 5h2.986l.69-5H8.852z" }) }) }), "三、现代系统的典型实现"] }), "\n", _jsxs(_components.ol, { children: ["\n", _jsxs(_components.li, { children: ["\n", _jsxs(_components.p, { children: [_jsx(_components.strong, { children: "x86 架构" }), "：采用段页式混合管理"] }), "\n", _jsxs(_components.ul, { children: ["\n", _jsx(_components.li, { children: "先通过段机制进行逻辑地址转换（现代 OS 通常设为平坦模式）" }), "\n", _jsx(_components.li, { children: "再通过多级页表（如 4 级页表）转换线性地址到物理地址" }), "\n"] }), "\n"] }), "\n", _jsxs(_components.li, { children: ["\n", _jsxs(_components.p, { children: [_jsx(_components.strong, { children: "进程切换代价" }), "："] }), "\n", _jsxs(_components.ul, { children: ["\n", _jsx(_components.li, { children: "页表切换：需更新 CR3 寄存器（TLB 会失效）" }), "\n", _jsx(_components.li, { children: "段表切换：修改段寄存器（如 GDTR/LDTR）" }), "\n"] }), "\n"] }), "\n"] })] }); } function MDXContent(props = {}) { const {wrapper: MDXLayout} = { ..._provideComponents(), ...props.components }; return MDXLayout ? _jsx(MDXLayout, { ...props, children: _jsx(_createMdxContent, { ...props }) }) : _createMdxContent(props); } return { default: MDXContent };

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