{"id":128,"date":"2005-08-30T06:33:14","date_gmt":"2005-08-29T22:33:14","guid":{"rendered":"http:\/\/tmp.xujiwei.com\/blog\/?p=128"},"modified":"2010-01-29T13:00:24","modified_gmt":"2010-01-29T05:00:24","slug":"string-operating-in-asm","status":"publish","type":"post","link":"https:\/\/xujiwei.com\/blog\/2005\/08\/string-operating-in-asm\/","title":{"rendered":"\u7528\u6c47\u7f16\u5b9e\u73b0\u7b26\u4e32\u64cd\u4f5c\u51fd\u6570"},"content":{"rendered":"

\u4e0d\u7ba1\u662f\u5728\u7cfb\u7edf\u5f00\u53d1\u8fd8\u662f\u5728\u5e73\u65f6\u7684\u7f16\u7a0b\u5f53\u4e2d\uff0c\u5b57\u7b26\u4e32\u64cd\u4f5c\u90fd\u662f\u5f88\u91cd\u8981\u7684\u4e00\u90e8\u5206\u3002\u5728C\u4e2d\uff0c\u5df2\u7ecf\u6709\u5e93\u63d0\u4f9b\u4e86strcpy\u3001strcmp\u3001strcat\u7b49\u51fd\u6570\uff0c \u800c\u5728\u5f00\u53d1\u7528\u6c47\u7f16\u5f00\u53d1\u81ea\u5df1\u7684\u7cfb\u7edf\u65f6\uff0c\u5e76\u6ca1\u6709\u73b0\u5728\u7684\u5e93\u53ef\u7528\uff0c\u8fd9\u5c31\u8981\u6c42\u6211\u4eec\u81ea\u5df1\u6765\u5b9e\u73b0\u5b57\u7b26\u4e32\u64cd\u4f5c\u4e86\u3002\u4ee5\u4e0b\u5982\u679c\u6ca1\u6709\u7279\u522b\u8bf4\u660e\uff0c\u5b57\u7b26\u4e32\u5747\u4ee50\u4e3a\u7ed3\u675f\u6807\u5fd7\u3002<\/p>\n

strcpy\u00a0\u5b57 \u7b26\u4e32\u590d\u5236<\/p>\n

\u5728\u5b57\u7b26\u4e32\u590d\u5236\u5f53\u4e2d\uff0c\u4e3a\u4e86\u7b80\u4fbf\uff0c\u53ef\u4ee5\u50cf\u5728C\u4e2d\u4e00\u6837\uff0c\u4e0d\u8003\u8651\u8fb9\u754c\u95ee\u9898\uff0c\u628a\u8fd9\u4e2a\u95ee\u9898\u4ea4\u8c03\u7528\u8005\uff0c\u4e0d\u8fc7\u8fd9\u6837\u5c31\u6709\u53ef\u80fd\u4ea7\u751f\u7f13\u51b2\u533a\u6ea2\u51fa \u4e86\uff1a\uff09\u5b57\u7b26\u4e32\u590d\u5236\u8fd8\u662f\u6bd4\u8f83\u5bb9\u6613\u5b9e\u73b0\u7684\uff0c\u53ea\u8981\u5728\u590d\u5236\u6bcf\u4e00\u4e2a\u5b57\u8282\u4e4b\u524d\u5224\u65ad\u662f\u4e0d\u662f0\uff0c\u5982\u679c\u662f\u5c31\u7ed3\u675f\uff0c\u4e0d\u662f\u5219\u7ee7\u7eed\u590d\u5236\u4e0b\u4e00\u4e2a\u5b57\u8282\u3002\u6211\u7ed9\u51fa\u4e00\u4e2a\u7b80\u5355\u7684\u4f8b\u5b50\uff0c\u5f53\u7136\uff0c\u4f60 \u53ef\u4ee5\u628a\u5b83\u4f18\u5316\u4ee5\u4ea7\u751f\u66f4\u597d\u7684\u6027\u80fd\u3002<\/p>\n

strcpy:<\/p>\n

;\u00a0in\u00a0\u00a0si\u00a0\u6e90\u5b57\u7b26\u4e32\u8d77\u59cb\u5730\u5740<\/p>\n

;\u00a0\u00a0\u00a0\u00a0\u00a0di\u00a0\u76ee\u6807\u5730 \u5740<\/p>\n

;\u00a0out\u00a0\u65e0<\/p>\n

push\u00a0si<\/p>\n

push\u00a0di\u00a0\u00a0;\u00a0\u4fdd\u62a4\u5bc4\u5b58\u5668<\/p>\n

next:<\/p>\n

lodsb\u00a0\u00a0\u00a0\u00a0;\u00a0\u8f7d \u5165\u4e00\u4e2a\u5b57\u8282<\/p>\n

or\u00a0al,al\u00a0\u00a0;\u00a0\u662f0\u5417\uff1f<\/p>\n

je\u00a0end\u00a0\u00a0;\u00a0\u662f\u5219\u7ed3\u675f<\/p>\n

stosb\u00a0\u00a0\u00a0;\u00a0\u4e0d \u662f\u5219\u653e\u5165\u76ee\u6807\u4e2d<\/p>\n

jmp\u00a0next\u00a0;\u00a0\u7ee7\u7eed\u4e0b\u4e00\u4e2a\u5b57\u8282<\/p>\n

end:<\/p>\n

mov\u00a0[di],byte\u00a00\u00a0\u00a0;\u00a0\u7ed3 \u675f\u6807\u5fd7<\/p>\n

pop\u00a0di\u00a0\u00a0;\u00a0\u6062\u590d\u5bc4\u5b58\u5668<\/p>\n

pop\u00a0si<\/p>\n

ret<\/p>\n

strlen\u00a0\u53d6 \u5b57\u7b26\u4e32\u957f\u5ea6<\/p>\n

\u5e94\u8be5\u8bf4\uff0c\u8fd9\u4e00\u4e2a\u6bd4\u4e0a\u4e00\u4e2a\u5bb9\u6613\uff0c\u56e0\u4e3a\u8fd9\u4e2a\u53ea\u9700\u8981\u8003\u8651\u4ec0\u4e48\u7ed3\u675f\uff0c\u800c\u4e0d\u9700\u8981\u53bb\u590d\u5236\u5b57\u8282\u3002<\/p>\n

strlen:<\/p>\n

;\u00a0in\u00a0si\u00a0\u6e90 \u5b57\u7b26\u4e32<\/p>\n

;\u00a0out\u00a0ax\u00a0\u5b57\u7b26\u4e32\u957f\u5ea6<\/p>\n

push\u00a0si<\/p>\n

push\u00a0cx\u00a0\u00a0\u00a0\u00a0;\u00a0\u4fdd\u62a4\u5bc4\u5b58\u5668<\/p>\n

xor\u00a0cx,cx\u00a0\u00a0;\u00a0\u8ba1 \u6570\u5668\u6e05\u96f6<\/p>\n

next:<\/p>\n

lodsb\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0;\u00a0\u8f7d\u5165\u4e00\u4e2a\u5b57\u8282<\/p>\n

or\u00a0al,al\u00a0\u00a0\u00a0\u00a0\u00a0;\u00a0\u662f0\uff1f<\/p>\n

je\u00a0end\u00a0\u00a0\u00a0\u00a0\u00a0;\u00a0\u662f \u5219\u7ed3\u675f<\/p>\n

inc\u00a0cx\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0;\u00a0\u5b57\u7b26\u4e32\u957f\u5ea6\uff0b1<\/p>\n

jmp\u00a0next\u00a0;\u00a0\u7ee7\u7eed\u4e0b\u4e00\u4e2a\u5b57\u8282<\/p>\n

end:<\/p>\n

mov\u00a0ax,cx\u00a0;\u00a0\u5c06 \u5b57\u7b26\u4e32\u957f\u5ea6\u653e\u5230AX\u4e2d\u4f5c\u4e3a\u8fd4\u56de\u503c<\/p>\n

pop\u00a0bx\u00a0\u00a0\u00a0\u00a0\u00a0;\u00a0\u6062\u590d\u5bc4\u5b58\u5668<\/p>\n

pop\u00a0si<\/p>\n

ret<\/p>\n

strcat\u00a0\u5b57 \u7b26\u4e32\u8fde\u63a5<\/p>\n

\u5c31\u4e2a\u4eba\u6765\u8bf4\uff0c\u5b57\u7b26\u4e32\u8fde\u63a5\u7528\u5f97\u5e76\u4e0d\u662f\u5f88\u591a\uff0c\u4f46\u65e2\u7136\u5728C\u4e2d\u6709\u8fd9\u4e2a\u51fd\u6570\uff0c\u5c31\u5fc5\u7136\u6709\u5b83\u5b58\u5728\u7684\u7406\u7531\uff0c\u6240\u4ee5\u6211\u4eec\u8fd8\u662f\u6709\u5fc5\u8981\u6765\u5b9e\u73b0\u5b83\u7684\u3002 \u540c\u6837\u7684\uff0c\u5728\u5b57\u7b26\u4e32\u8fde\u63a5\u65f6\u4e0d\u8003\u8651\u76ee\u6807\u7f13\u51b2\u533a\u662f\u5426\u8db3\u591f\u7684\u95ee\u9898\uff0c\u628a\u8fd9\u4e2a\u4ea4\u7ed9\u8c03\u7528\u8005\u3002<\/p>\n

\u8981\u5c06\u4e00\u4e2a\u5b57\u7b26\u4e32\u8fde\u63a5\u5230\u53e6\u4e00\u4e2a\u5b57\u7b26\u4e4b\u540e\uff0c\u5c31\u9700\u8981\u5148\u627e\u51fa\u76ee \u6807\u5b57\u7b26\u4e32\u7684\u7ed3\u5c3e\uff0c\u53730\u7684\u5730\u5740\uff0c\u7136\u540e\u5c31\u53ef\u4ee5\u628a\u8fd9\u4e2a\u5730\u5740\u505a\u4e3a\u76ee\u6807\uff0c\u628a\u9700\u8981\u8fde\u63a5\u7684\u5b57\u7b26\u4e32\u7684\u9996\u5730\u5740\u505a\u4e3a\u6e90\uff0c\u8c03\u7528strcpy\u5373\u53ef\u5b8c\u6210\u3002\u800c\u627e\u51fa0\u7684\u5730\u5740\uff0c\u539f\u7406\u548c\u53d6\u5b57 \u7b26\u4e32\u957f\u5ea6\u4e00\u6837\uff0c\u8f7d\u5165\u4e00\u4e2a\u5b57\u8282\u7136\u540e\u5224\u65ad\u662f\u5426\u4e3a0\u3002\u8fd9\u4e2a\u7559\u5927\u5bb6\u81ea\u5df1\u53bb\u5b9e\u73b0\u3002<\/p>\n

\u4e0a\u9762\u7684\u4f8b\u5b50\u4f7f\u7528\u7684\u5bc4\u5b58\u5668\u90fd\u662f16\u4f4d\u7684\uff0c\u6240\u4ee5\u53ea\u80fd\u7528\u572816\u4f4d\u7684 \u7a0b\u5e8f\u5f53\u4e2d\uff0c\u5f53\u7136\uff0c\u5982\u679c\u662f\u4f60\u81ea\u5df1\u5199\u7684\uff0c\u90a3\u4e48\u81ea\u5df1\u61c2\u5f97\u5b83\u5b9e\u73b0\u7684\u539f\u7406\uff0c\u79fb\u690d\u523032\u4f4d\u5c31\u662f\u4ef6\u5f88\u5bb9\u6613\u7684\u4e8b\u3002<\/p>\n

\u4eca\u5929\u8fd9\u7bc7\u5c31\u5230\u8fd9\u91cc\u55bd\uff5e\uff5e\u96be\u5f97\u5199\u6559 \u7a0b\u4e4b\u7c7b\u7684\u6587\u7ae0\uff0c\u4eca\u5929\u8fd8\u7b97\u987a\u624b^-^\uff5e\uff5e<\/p>\n","protected":false},"excerpt":{"rendered":"

\u4e0d\u7ba1\u662f\u5728\u7cfb\u7edf\u5f00\u53d1\u8fd8\u662f\u5728\u5e73\u65f6\u7684\u7f16\u7a0b\u5f53\u4e2d\uff0c\u5b57\u7b26\u4e32\u64cd\u4f5c\u90fd\u662f\u5f88\u91cd\u8981\u7684\u4e00\u90e8\u5206\u3002\u5728C\u4e2d\uff0c\u5df2\u7ecf …<\/p>\n

\u7ee7\u7eed\u9605\u8bfb »<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[5],"tags":[80,86],"_links":{"self":[{"href":"https:\/\/xujiwei.com\/blog\/wp-json\/wp\/v2\/posts\/128"}],"collection":[{"href":"https:\/\/xujiwei.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/xujiwei.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/xujiwei.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/xujiwei.com\/blog\/wp-json\/wp\/v2\/comments?post=128"}],"version-history":[{"count":0,"href":"https:\/\/xujiwei.com\/blog\/wp-json\/wp\/v2\/posts\/128\/revisions"}],"wp:attachment":[{"href":"https:\/\/xujiwei.com\/blog\/wp-json\/wp\/v2\/media?parent=128"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/xujiwei.com\/blog\/wp-json\/wp\/v2\/categories?post=128"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/xujiwei.com\/blog\/wp-json\/wp\/v2\/tags?post=128"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}