{"id":145,"date":"2017-11-10T00:36:53","date_gmt":"2017-11-09T16:36:53","guid":{"rendered":"http:\/\/www.hyh0.com\/?p=145"},"modified":"2017-11-10T00:37:18","modified_gmt":"2017-11-09T16:37:18","slug":"4-%e7%94%a8call%e4%b8%8eret%e5%ae%9e%e7%8e%b0%e6%b1%87%e7%bc%96%e7%9a%84%e6%a8%a1%e5%9d%97%e5%8c%96%e7%bc%96%e7%a8%8b","status":"publish","type":"post","link":"https:\/\/www.hyh0.com\/?p=145","title":{"rendered":"4. \u7528call\u4e0eret\u5b9e\u73b0\u6c47\u7f16\u7684\u6a21\u5757\u5316\u7f16\u7a0b"},"content":{"rendered":"<p>call \u548c ret \u90fd\u662f\u8f6c\u79fb\u6307\u4ee4\uff0c\u4ed6\u4eec\u53ef\u4ee5\u5171\u540c\u4f7f\u7528\u5b9e\u73b0\u6c47\u7f16\u4e2d\u7684\u4e2d\u7684\u5b50\u7a0b\u5e8f\u8bbe\u8ba1<\/p>\n<p><!--more--><\/p>\n<h4 style=\"text-align: center;\">call \u6307\u4ee4<\/h4>\n<h5>call \u8fd1\u8f6c\u79fb<\/h5>\n<p>\u4f7f\u7528\u683c\u5f0f\uff1acall label<\/p>\n<p>\u5f53\u6267\u884ccall\u6307\u4ee4\u65f6\uff0cCPU\u53ef\u4ee5\u8ba4\u4e3a\u6267\u884c2\u4e2a\u64cd\u4f5c\uff1a<\/p>\n<ol>\n<li>push ip + 3 (\u5c06call\u540e\u7684\u4e0b\u4e00\u6761\u6307\u4ee4\u7684ip\u538b\u5165\u6808\u4e2d)<\/li>\n<li>jmp near ptr label (\u8df3\u8f6c\u5230label\u6240\u5728\u7684ip)<\/li>\n<\/ol>\n<h5>call \u8fdc\u8f6c\u79fb<\/h5>\n<p>\u5f53\u8981\u8fdb\u884c\u6bb5\u95f4\u8f6c\u79fb\u65f6\uff0c\u4f7f\u7528 call far ptr \u6307\u4ee4(\u5728emu8086\u4e2d\u65e0\u6548\uff0c\u53ef\u4ee5\u7528&#8217;\u8f6c\u79fb\u5730\u5740\u5728\u5185\u5b58\u4e2d\u7684call&#8217;\u4ee3\u66ff)\uff0c\u8be5\u6307\u4ee4\u4f1a\u5c06\u5f53\u524d\u7684cs\u4e0eip\u5148\u540e\u538b\u5165\u6808\u4e2d\uff0c\u5e76\u8fdb\u884c\u7b49\u6548\u4e8e jmp far ptr \u7684\u8df3\u8f6c<\/p>\n<h5>\u8f6c\u79fb\u5730\u5740\u5728\u5bc4\u5b58\u5668\u4e2d\u7684call\u6307\u4ee4<\/h5>\n<p>\u683c\u5f0f\uff1acall reg\uff0c\u5728\u628a\u5f53\u524dIP\u538b\u5165\u6808\u4e2d\u540e\u8df3\u8f6c\u523016reg\u4e2d\u7684\u5730\u5740<\/p>\n<h5>\u8f6c\u79fb\u5730\u5740\u5728\u5185\u5b58\u4e2d\u7684call\u6307\u4ee4<\/h5>\n<p>\u5206\u4e3a\u4e24\u7c7b\uff0c\u8fd1\u8f6c\u79fb\u4e0e\u8fdc\u8f6c\u79fb<\/p>\n<p>call word ptr [Address]<br \/>\ncall dword ptr [Address]<\/p>\n<pre class=\"brush: plain; title: ; notranslate\" title=\"\">\r\nmov word ptr [0], func ;\u504f\u79fb\u5730\u5740\r\nmov word ptr [2], code ;\u6bb5\u5730\u5740\r\ncall dword ptr [0]\r\n<\/pre>\n<h4 style=\"text-align: center;\">ret \u4e0e retf \u6307\u4ee4<\/h4>\n<p>\u4e0ecall\u6307\u4ee4\u5bf9\u5e94\u7684\uff0cret\u4e0eretf\u6307\u4ee4\u4ece\u6808\u4e2d\u83b7\u5f97\u8df3\u8f6c\u5730\u5740\u8fdb\u884c\u8df3\u8f6c\u3002ret\u6307\u4ee4\u5bf9\u5e94call\u7684\u8fd1\u8f6c\u79fb\uff0c\u4ece\u6808\u4e2d\u5f39\u51fa\u4e00\u4e2a\u5730\u5740\u7ed9ip\u3002retf\u5bf9\u5e94\u8fdc\u8f6c\u79fb\uff0c\u4ece\u6808\u4e2d\u5f39\u51fa\u4e24\u4e2a\u5143\u7d20\u5206\u522b\u4fee\u6539ip\u4e0ecs<\/p>\n<p>ret \u6307\u4ee4\u8fd8\u53ef\u4ee5\u4e0e\u7acb\u5373\u6570\u4e00\u8d77\u4f7f\u7528\uff0c\u5982 ret N \u53ef\u4ee5\u8ba4\u4e3a\u662f\uff1a<\/p>\n<ol>\n<li>pop ip<\/li>\n<li>add sp, N<\/li>\n<\/ol>\n<p>\u8fd9\u6837\u53ef\u4ee5\u5b9e\u73b0\u7528\u6808\u6765\u8f6c\u9012\u53c2\u6570<\/p>\n<h4 style=\"text-align: center;\">\u6c47\u7f16\u7684\u6a21\u5757\u5316\u7f16\u7a0b<\/h4>\n<p>\u4f7f\u7528call\u4e0eret\u53ef\u4ee5\u5b9e\u73b0\u5bf9\u5b50\u7a0b\u5e8f\u7684\u8c03\u7528\u4e0e\u8fd4\u56de<\/p>\n<p>\u5982\u4ee5\u4e0b\u5b50\u7a0b\u5e8f\u5b9e\u73b0\u4e86\u8ba1\u7b97ax\u7684\u7acb\u65b9\uff1a<\/p>\n<pre class=\"brush: plain; title: ; notranslate\" title=\"\">\r\n; \u63cf\u8ff0\uff1a\u8ba1\u7b97N\u7684\u7acb\u65b9\u6839\r\n; \u53c2\u6570\uff1a(ax) = N\r\n; \u7ed3\u679c\uff1a(bx ax) = N^3\r\ncube:\r\n    push cx    ; \u4fdd\u5b58cx\u4e2d\u539f\u6765\u7684\u5143\u7d20\r\n    mov cx, ax ; \u7528cx\u4fdd\u5b58ax\r\n    mul cx     ; \u8ba1\u7b97N^2\r\n    mul cx     ; \u8ba1\u7b97N^3\r\n    pop cx     ; \u6062\u590dcx\r\n    ret        ; \u8fd4\u56de\r\n<\/pre>\n<p>\u8fd9\u91cc\u4f7f\u7528\u4e86\u5bc4\u5b58\u5668\u6765\u8f6c\u9012\u53c2\u6570\uff0c\u66f4\u5e38\u7528\u7684\u4f5c\u6cd5\u662f\u4f7f\u7528\u6808\u6765\u4f20\u9012\u53c2\u6570\uff0c\u5982\u540c\u6837\u7684\u7a0b\u5e8f\u53ef\u4ee5\u6539\u5199\u4e3a\uff1a<\/p>\n<pre class=\"brush: plain; title: ; notranslate\" title=\"\">\r\n; \u63cf\u8ff0\uff1a\u8ba1\u7b97N\u7684\u7acb\u65b9\u6839\r\n; \u53c2\u6570: N = \u6808\u4e2d\u9664IP\u5916\u7684\u7b2c\u4e8c\u4e2a\u5143\u7d20\r\n; \u8fd4\u56de\uff1a(bax ax) = N^3 \r\ncube2:\r\n    push bp            ; \u4fdd\u5b58bp\r\n    mov bp, sp         ; \u5c06bp\u6307\u5411\u6808\u9876\r\n    mov ax, ss:[bp+4]  ; \u4ece\u6808\u4e2d\u83b7\u5f97\u53c2\u6570\r\n    mov bp, ax         ; \u8ba1\u7b97N^3\r\n    mul bp\r\n    mul bp\r\n    pop bp             ; \u6062\u590dbp\r\n    ret 2              ; \u5c06\u6808\u9876\u6307\u5411\u53c2\u6570\u524d,\u5e76\u8fd4\u56de\r\n<\/pre>\n<p>\u8c03\u7528\u65f6\u5219\uff1a<\/p>\n<pre class=\"brush: plain; title: ; notranslate\" title=\"\">\r\npush 2\r\ncall cube2\r\n<\/pre>\n<p>\u8fd8\u53ef\u4ee5\u7528\u5bc4\u5b58\u5668\/\u6808\u8f6c\u9012\u5730\u5740\uff0c\u5b50\u7a0b\u5e8f\u4ece\u5185\u5b58\u4e2d\u83b7\u5f97\u6570\u636e(\u5e38\u7528\u4e8e\u6279\u91cf\u6570\u636e\u7684\u4f20\u9012)\uff0c\u4ee5\u4e0b\u7a0b\u5e8f\u4f7f\u7528\u8fd9\u79cd\u65b9\u6cd5\u5728\u5c4f\u5e55\u7684\u6307\u5b9a\u4f4d\u7f6e\u6253\u5370\u5185\u5b58\u4e2d\u7684\u6570\u636e\uff1a<\/p>\n<pre class=\"brush: plain; title: ; notranslate\" title=\"\">\r\n; \u63cf\u8ff0\uff1a\u5728\u5c4f\u5e55\u7684\u6307\u5b9a\u4f4d\u7f6e\u6253\u5370\u5b57\u7b26\u4e32\r\n; \u53c2\u6570\uff1a\u8d77\u59cb\u4f4d\u7f6e &lt;- \u6808\u4e2d\u7b2c5\u4e2a\u5143\u7d20 \r\n;       \u957f\u5ea6     &lt;- \u6808\u4e2d\u7b2c4\u4e2a\u5143\u7d20\r\n;       Y\u4f4d\u7f6e    &lt;- \u6808\u4e2d\u7b2c3\u4e2a\u5143\u7d20\r\n;       X\u4f4d\u7f6e    &lt;- \u6808\u4e2d\u7b2c2\u4e2a\u5143\u7d20\r\n; \u7ed3\u679c\uff1a\u65e0\r\nprint:\r\n    push ax   ;\u4e2d\u8f6c\r\n    push bx   ;\u5b57\u7b26\u4e32\u5bfb\u5740\r\n    push cx   ;\u63a7\u5236\u5faa\u73af\r\n    push si   ;\u8f93\u51fa\u504f\u79fb\u5730\u5740\r\n    push es   ;\u8f93\u51fa\u6bb5\u5730\u5740\r\n    \r\n    mov bx, sp\r\n    mov ax, ss:[bx+14] ;\u83b7\u5f97\u8f93\u51fa\u7684\u504f\u79fb\u4f4d\u7f6e\r\n    mov cl, 158\r\n    mul cl\r\n    mov si, ax\r\n    mov ax, ss:[bx+12]\r\n    add si, ax\r\n    add si, ax       \r\n    mov cx, ss:[bx+16] ;\u83b7\u5f97\u957f\u5ea6\r\n    mov bx, ss:[bx+18] ;\u83b7\u5f97\u5b57\u7b26\u4e32\u5730\u5740\r\n    \r\n    mov ax, 0B800H\r\n    mov es, ax        ;\u83b7\u5f97\u8f93\u51fa\u7684\u6bb5\u5730\u5740\r\n    \r\n    print_loop:\r\n        mov al, [bx]      ;\u83b7\u5f97\u5b57\u7b26\r\n        mov es:[si], al   ;\u8f93\u51fa\r\n        add bx, 1\r\n        add si, 2\r\n    loop print_loop\r\n    \r\n    pop es\r\n    pop si    \r\n    pop cx\r\n    pop bx\r\n    pop ax\r\n    ret 8\r\n<\/pre>\n<p>\u8fd8\u6709\u8981\u6ce8\u610f\u8bbe\u8ba1\u5b50\u7a0b\u5e8f\u65f6\uff0c\u8981\u6ce8\u610f\u5bc4\u5b58\u5668\u51b2\u7a81(\u5b50\u7a0b\u5e8f\u4fee\u6539\u4e86\u4e3b\u7a0b\u5e8f\u8981\u7528\u7684\u5bc4\u5b58\u5668)\uff0c\u89e3\u51b3\u65b9\u6848\u4e00\u4e2a\u65f6\u907f\u514d\u4f7f\u7528\u51b2\u7a81\u7684\u5bc4\u5b58\u5668\uff0c\u53e6\u4e00\u4e2a\u5219\u662f\u63d0\u524d\u5c06\u5bc4\u5b58\u5668\u7684\u503c\u538b\u5165\u6808\u4e2d\uff0c\u5b50\u7a0b\u5e8f\u8fd4\u56de\u524d\u518d\u4ece\u6808\u4e2d\u5f39\u51fa<\/p>\n","protected":false},"excerpt":{"rendered":"<p>call \u548c ret \u90fd\u662f\u8f6c\u79fb\u6307\u4ee4\uff0c\u4ed6\u4eec\u53ef\u4ee5\u5171\u540c\u4f7f\u7528\u5b9e\u73b0\u6c47\u7f16\u4e2d\u7684\u4e2d\u7684\u5b50\u7a0b\u5e8f\u8bbe\u8ba1<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[7],"tags":[],"_links":{"self":[{"href":"https:\/\/www.hyh0.com\/index.php?rest_route=\/wp\/v2\/posts\/145"}],"collection":[{"href":"https:\/\/www.hyh0.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hyh0.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hyh0.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hyh0.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=145"}],"version-history":[{"count":8,"href":"https:\/\/www.hyh0.com\/index.php?rest_route=\/wp\/v2\/posts\/145\/revisions"}],"predecessor-version":[{"id":155,"href":"https:\/\/www.hyh0.com\/index.php?rest_route=\/wp\/v2\/posts\/145\/revisions\/155"}],"wp:attachment":[{"href":"https:\/\/www.hyh0.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=145"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hyh0.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=145"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hyh0.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=145"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}