kernel: string.h, gdt, msr, cpu and ist

kernel-src/lib/string.c

@@ -0,0 +1,68 @@
+#include <string.h>
+#include <stddef.h>
+#include <stdint.h>
+
+void *memcpy(void *d, void *s, size_t c) {
+        uint8_t *sc = (uint8_t *)s;
+        uint8_t *dc = (uint8_t *)d;
+
+        while(c--)
+                *dc++ = *sc++;
+
+        return d;
+}
+
+void *memset(void *ptr, unsigned long value, size_t num) {
+        char *p = (char *)ptr;
+        while(num--)
+                *p++ = value;
+
+        return ptr;
+}
+
+char *strcat(char *dest, const char *src) {
+	dest += strlen(dest);
+
+	strcpy(dest, src);
+
+	return dest;
+	
+}
+int strcmp(const char *a, const char *b) {
+        while(*a && (*a == *b)) {
+		++a;
+		++b;
+	}
+
+        return  *(const unsigned char *)a - *(const unsigned char *)b;
+}
+
+char *strcpy(char *p, const char *s) {
+	const char *temp1 = s;
+	char *temp2 = p;
+	while(*temp1 != '\0') {
+		*temp2 = *temp1;
+		temp1++;
+		temp2++;
+	}
+	*temp2 = '\0';
+	return p;
+}
+
+size_t strlen(const char *a) {
+        size_t s = 0;
+
+        while(a[s] != '\0')
+		++s;
+
+        return s;
+}
+
+int strncmp(const char *a, const char *b, size_t c) {
+        int diff = 0;
+
+        while(c-- && diff == 0)
+                diff += *a++ - *b++;
+
+        return diff;
+}