1 files changed, 257 insertions, 0 deletions
diff --git a/arch/i386/lib/string.c b/arch/i386/lib/string.c
new file mode 100644
index 00000000000..2c773fefa3d
--- /dev/null
+++ b/arch/i386/lib/string.c
@@ -0,0 +1,257 @@
+/*
+ * Most of the string-functions are rather heavily hand-optimized,
+ * see especially strsep,strstr,str[c]spn. They should work, but are not
+ * very easy to understand. Everything is done entirely within the register
+ * set, making the functions fast and clean. String instructions have been
+ * used through-out, making for "slightly" unclear code :-)
+ *
+ * AK: On P4 and K7 using non string instruction implementations might be faster
+ * for large memory blocks. But most of them are unlikely to be used on large
+ * strings.
+ */
+
+#include <linux/string.h>
+#include <linux/module.h>
+
+#ifdef __HAVE_ARCH_STRCPY
+char *strcpy(char * dest,const char *src)
+{
+	int d0, d1, d2;
+	asm volatile( "1:\tlodsb\n\t"
+		"stosb\n\t"
+		"testb %%al,%%al\n\t"
+		"jne 1b"
+		: "=&S" (d0), "=&D" (d1), "=&a" (d2)
+		:"0" (src),"1" (dest) : "memory");
+	return dest;
+}
+EXPORT_SYMBOL(strcpy);
+#endif
+
+#ifdef __HAVE_ARCH_STRNCPY
+char *strncpy(char * dest,const char *src,size_t count)
+{
+	int d0, d1, d2, d3;
+	asm volatile( "1:\tdecl %2\n\t"
+		"js 2f\n\t"
+		"lodsb\n\t"
+		"stosb\n\t"
+		"testb %%al,%%al\n\t"
+		"jne 1b\n\t"
+		"rep\n\t"
+		"stosb\n"
+		"2:"
+		: "=&S" (d0), "=&D" (d1), "=&c" (d2), "=&a" (d3)
+		:"0" (src),"1" (dest),"2" (count) : "memory");
+	return dest;
+}
+EXPORT_SYMBOL(strncpy);
+#endif
+
+#ifdef __HAVE_ARCH_STRCAT
+char *strcat(char * dest,const char * src)
+{
+	int d0, d1, d2, d3;
+	asm volatile( "repne\n\t"
+		"scasb\n\t"
+		"decl %1\n"
+		"1:\tlodsb\n\t"
+		"stosb\n\t"
+		"testb %%al,%%al\n\t"
+		"jne 1b"
+		: "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
+		: "0" (src), "1" (dest), "2" (0), "3" (0xffffffffu): "memory");
+	return dest;
+}
+EXPORT_SYMBOL(strcat);
+#endif
+
+#ifdef __HAVE_ARCH_STRNCAT
+char *strncat(char * dest,const char * src,size_t count)
+{
+	int d0, d1, d2, d3;
+	asm volatile( "repne\n\t"
+		"scasb\n\t"
+		"decl %1\n\t"
+		"movl %8,%3\n"
+		"1:\tdecl %3\n\t"
+		"js 2f\n\t"
+		"lodsb\n\t"
+		"stosb\n\t"
+		"testb %%al,%%al\n\t"
+		"jne 1b\n"
+		"2:\txorl %2,%2\n\t"
+		"stosb"
+		: "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
+		: "0" (src),"1" (dest),"2" (0),"3" (0xffffffffu), "g" (count)
+		: "memory");
+	return dest;
+}
+EXPORT_SYMBOL(strncat);
+#endif
+
+#ifdef __HAVE_ARCH_STRCMP
+int strcmp(const char * cs,const char * ct)
+{
+	int d0, d1;
+	int res;
+	asm volatile( "1:\tlodsb\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"
+		"2:\tsbbl %%eax,%%eax\n\t"
+		"orb $1,%%al\n"
+		"3:"
+		:"=a" (res), "=&S" (d0), "=&D" (d1)
+		:"1" (cs),"2" (ct)
+		:"memory");
+	return res;
+}
+EXPORT_SYMBOL(strcmp);
+#endif
+
+#ifdef __HAVE_ARCH_STRNCMP
+int strncmp(const char * cs,const char * ct,size_t count)
+{
+	int res;
+	int d0, d1, d2;
+	asm volatile( "1:\tdecl %3\n\t"
+		"js 2f\n\t"
+		"lodsb\n\t"
+		"scasb\n\t"
+		"jne 3f\n\t"
+		"testb %%al,%%al\n\t"
+		"jne 1b\n"
+		"2:\txorl %%eax,%%eax\n\t"
+		"jmp 4f\n"
+		"3:\tsbbl %%eax,%%eax\n\t"
+		"orb $1,%%al\n"
+		"4:"
+		:"=a" (res), "=&S" (d0), "=&D" (d1), "=&c" (d2)
+		:"1" (cs),"2" (ct),"3" (count)
+		:"memory");
+	return res;
+}
+EXPORT_SYMBOL(strncmp);
+#endif
+
+#ifdef __HAVE_ARCH_STRCHR
+char *strchr(const char * s, int c)
+{
+	int d0;
+	char * res;
+	asm volatile( "movb %%al,%%ah\n"
+		"1:\tlodsb\n\t"
+		"cmpb %%ah,%%al\n\t"
+		"je 2f\n\t"
+		"testb %%al,%%al\n\t"
+		"jne 1b\n\t"
+		"movl $1,%1\n"
+		"2:\tmovl %1,%0\n\t"
+		"decl %0"
+		:"=a" (res), "=&S" (d0)
+		:"1" (s),"0" (c)
+		:"memory");
+	return res;
+}
+EXPORT_SYMBOL(strchr);
+#endif
+
+#ifdef __HAVE_ARCH_STRRCHR
+char *strrchr(const char * s, int c)
+{
+	int d0, d1;
+	char * res;
+	asm volatile( "movb %%al,%%ah\n"
+		"1:\tlodsb\n\t"
+		"cmpb %%ah,%%al\n\t"
+		"jne 2f\n\t"
+		"leal -1(%%esi),%0\n"
+		"2:\ttestb %%al,%%al\n\t"
+		"jne 1b"
+		:"=g" (res), "=&S" (d0), "=&a" (d1)
+		:"0" (0),"1" (s),"2" (c)
+		:"memory");
+	return res;
+}
+EXPORT_SYMBOL(strrchr);
+#endif
+
+#ifdef __HAVE_ARCH_STRLEN
+size_t strlen(const char * s)
+{
+	int d0;
+	int res;
+	asm volatile( "repne\n\t"
+		"scasb\n\t"
+		"notl %0\n\t"
+		"decl %0"
+		:"=c" (res), "=&D" (d0)
+		:"1" (s),"a" (0), "0" (0xffffffffu)
+		:"memory");
+	return res;
+}
+EXPORT_SYMBOL(strlen);
+#endif
+
+#ifdef __HAVE_ARCH_MEMCHR
+void *memchr(const void *cs,int c,size_t count)
+{
+	int d0;
+	void *res;
+	if (!count)
+		return NULL;
+	asm volatile( "repne\n\t"
+		"scasb\n\t"
+		"je 1f\n\t"
+		"movl $1,%0\n"
+		"1:\tdecl %0"
+		:"=D" (res), "=&c" (d0)
+		:"a" (c),"0" (cs),"1" (count)
+		:"memory");
+	return res;
+}
+EXPORT_SYMBOL(memchr);
+#endif
+
+#ifdef __HAVE_ARCH_MEMSCAN
+void *memscan(void * addr, int c, size_t size)
+{
+	if (!size)
+		return addr;
+	asm volatile("repnz; scasb\n\t"
+	    "jnz 1f\n\t"
+	    "dec %%edi\n"
+	    "1:"
+	    : "=D" (addr), "=c" (size)
+	    : "0" (addr), "1" (size), "a" (c)
+	    : "memory");
+	return addr;
+}
+EXPORT_SYMBOL(memscan);
+#endif
+
+#ifdef __HAVE_ARCH_STRNLEN
+size_t strnlen(const char *s, size_t count)
+{
+	int d0;
+	int res;
+	asm volatile( "movl %2,%0\n\t"
+		"jmp 2f\n"
+		"1:\tcmpb $0,(%0)\n\t"
+		"je 3f\n\t"
+		"incl %0\n"
+		"2:\tdecl %1\n\t"
+		"cmpl $-1,%1\n\t"
+		"jne 1b\n"
+		"3:\tsubl %2,%0"
+		:"=a" (res), "=&d" (d0)
+		:"c" (s),"1" (count)
+		:"memory");
+	return res;
+}
+EXPORT_SYMBOL(strnlen);
+#endif