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user/libs/libc/string.h

@@ -34,4 +34,35 @@ size_t strlen(const char *s)
         ++__res;
     }
     return __res;
+}
+
+
+/*
+        比较字符串 FirstPart and SecondPart
+        FirstPart = SecondPart =>  0
+        FirstPart > SecondPart =>  1
+        FirstPart < SecondPart => -1
+*/
+
+int strcmp(const char *FirstPart, const char *SecondPart)
+{
+    register int __res;
+    __asm__ __volatile__("cld	\n\t"
+                         "1:	\n\t"
+                         "lodsb	\n\t"
+                         "scasb	\n\t"
+                         "jne	2f	\n\t"
+                         "testb	%%al,	%%al	\n\t"
+                         "jne	1b	\n\t"
+                         "xorl	%%eax,	%%eax	\n\t"
+                         "jmp	3f	\n\t"
+                         "2:	\n\t"
+                         "movl	$1,	%%eax	\n\t"
+                         "jl	3f	\n\t"
+                         "negl	%%eax	\n\t"
+                         "3:	\n\t"
+                         : "=a"(__res)
+                         : "D"(FirstPart), "S"(SecondPart)
+                         :);
+    return __res;
 }