1 files changed, 172 insertions, 0 deletions
diff --git a/src/loader/library.c b/src/loader/library.c
new file mode 100644
index 0000000..4317a8e
--- /dev/null
+++ b/src/loader/library.c
@@ -0,0 +1,172 @@
+// MIT License, Copyright (c) 2021 Marvin Borner
+
+#include <library.h>
+
+/**
+ * Common string functions
+ */
+
+u32 strlen(const char *str)
+{
+	const char *s = str;
+	while (*s)
+		s++;
+	return s - str;
+}
+
+u32 strnlen(const char *str, u32 max)
+{
+	const char *s = str;
+	while (max && *s) {
+		s++;
+		max--;
+	}
+	return s - str;
+}
+
+u32 strlcpy(char *dst, const char *src, u32 size)
+{
+	const char *orig = src;
+	u32 left = size;
+
+	if (left)
+		while (--left)
+			if (!(*dst++ = *src++))
+				break;
+
+	if (!left) {
+		if (size)
+			*dst = 0;
+		while (*src++)
+			;
+	}
+
+	return src - orig - 1;
+}
+
+s32 strncmp(const char *s1, const char *s2, u32 n)
+{
+	const u8 *c1 = (const u8 *)s1;
+	const u8 *c2 = (const u8 *)s2;
+	u8 ch;
+	s32 d = 0;
+
+	while (n--) {
+		d = (s32)(ch = *c1++) - (s32)*c2++;
+		if (d || !ch)
+			break;
+	}
+
+	return d;
+}
+
+/**
+ * Common memory functions
+ */
+
+void *memcpy(void *dest, const void *src, u32 n)
+{
+	// Inspired by jgraef at osdev
+	u32 num_dwords = n / 4;
+	u32 num_bytes = n % 4;
+	u32 *dest32 = (u32 *)dest;
+	const u32 *src32 = (const u32 *)src;
+	u8 *dest8 = ((u8 *)dest) + num_dwords * 4;
+	const u8 *src8 = ((const u8 *)src) + num_dwords * 4;
+
+	__asm__ volatile("rep movsl\n"
+			 : "=S"(src32), "=D"(dest32), "=c"(num_dwords)
+			 : "S"(src32), "D"(dest32), "c"(num_dwords)
+			 : "memory");
+
+	for (u32 i = 0; i < num_bytes; i++)
+		dest8[i] = src8[i];
+
+	return dest;
+}
+
+void *memset(void *dest, u32 val, u32 n)
+{
+	// Inspired by jgraef at osdev
+	u32 uval = val;
+	u32 num_dwords = n / 4;
+	u32 num_bytes = n % 4;
+	u32 *dest32 = (u32 *)dest;
+	u8 *dest8 = ((u8 *)dest) + num_dwords * 4;
+	u8 val8 = (u8)val;
+	u32 val32 = uval | (uval << 8) | (uval << 16) | (uval << 24);
+
+	__asm__ volatile("rep stosl\n"
+			 : "=D"(dest32), "=c"(num_dwords)
+			 : "D"(dest32), "c"(num_dwords), "a"(val32)
+			 : "memory");
+
+	for (u32 i = 0; i < num_bytes; i++)
+		dest8[i] = val8;
+
+	return dest;
+}
+
+s32 memcmp(const void *s1, const void *s2, u32 n)
+{
+	const u8 *a = (const u8 *)s1;
+	const u8 *b = (const u8 *)s2;
+	for (u32 i = 0; i < n; i++) {
+		if (a[i] < b[i])
+			return -1;
+		else if (b[i] < a[i])
+			return 1;
+	}
+	return 0;
+}
+
+/**
+ * Conversion
+ */
+
+s32 itoa(s32 value, char *buffer, u32 base)
+{
+	char tmp[16];
+	char *tp = tmp;
+	s32 i;
+	unsigned v;
+
+	s32 sign = (base == 10 && value < 0);
+	if (sign)
+		v = -value;
+	else
+		v = (unsigned)value;
+
+	while (v || tp == tmp) {
+		i = v % base;
+		v /= base;
+		if (i < 10)
+			*tp++ = i + '0';
+		else
+			*tp++ = i + 'a' - 10;
+	}
+
+	s32 len = tp - tmp;
+
+	if (sign) {
+		*buffer++ = '-';
+		len++;
+	}
+
+	while (tp > tmp)
+		*buffer++ = *--tp;
+	*buffer = '\0';
+
+	return len;
+}
+
+// From stackoverflow
+s32 atoi(const char *inp)
+{
+	s32 ret = 0;
+	while (*inp) {
+		ret = (ret << 3) + (ret << 1) + (*inp) - '0';
+		inp++;
+	}
+	return ret;
+}