This adds several standard C functions to lib.c:
strncmp, toupper, isdigit, isxdigit

simple_strtoul is a limited implementation of strtoul, taken from Linux.

They will be needed for command line parsing.

Index: memtest86+-1.70/lib.c
===================================================================
--- memtest86+-1.70.orig/lib.c
+++ memtest86+-1.70/lib.c
@@ -69,6 +69,21 @@ int memcmp(const void *s1, const void *s
 	return 0;
 }
 
+int strncmp(const char *s1, const char *s2, ulong n)
+{
+	signed char res = 0;
+	while (n) {
+		res = *s1 - *s2;
+		if (res != 0)
+			return res;
+		if (*s1 == '\0')
+			return 0;
+		++s1, ++s2;
+		--n;
+	}
+	return res;
+}
+
 void *memmove(void *dest, const void *src, ulong n)
 {
 	long i;
@@ -87,6 +102,53 @@ void *memmove(void *dest, const void *sr
 	}
 	return dest;
 }
+
+char toupper(char c)
+{
+	if (c >= 'a' && c <= 'z')
+		return c + 'A' -'a';
+	else
+		return c;
+}
+
+int isdigit(char c)
+{
+	return c >= '0' && c <= '9';
+}
+
+int isxdigit(char c)
+{
+	return isdigit(c) || (toupper(c) >= 'A' && toupper(c) <= 'F');
+}
+
+unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
+{
+	unsigned long result = 0, value;
+
+	if (!base) {
+		base = 10;
+		if (*cp == '0') {
+			base = 8;
+			cp++;
+			if (toupper(*cp) == 'X' && isxdigit(cp[1])) {
+				cp++;
+				base = 16;
+			}
+		}
+	} else if (base == 16) {
+		if (cp[0] == '0' && toupper(cp[1]) == 'X')
+			cp += 2;
+	}
+	while (isxdigit(*cp) &&
+		(value = isdigit(*cp) ? *cp-'0' : toupper(*cp)-'A'+10) < base) {
+		result = result*base + value;
+		cp++;
+	}
+	if (endp)
+		*endp = (char *)cp;
+	return result;
+}
+
 /*
  * Scroll the error message area of the screen as needed
  * Starts at line LINE_SCROLL and ends at line 23
Index: memtest86+-1.70/test.h
===================================================================
--- memtest86+-1.70.orig/test.h
+++ memtest86+-1.70/test.h
@@ -95,6 +95,7 @@ typedef unsigned long ulong;
 #define getCx86(reg) ({ outb((reg), 0x22); inb(0x23); })
 int memcmp(const void *s1, const void *s2, ulong count);
 void *memmove(void *dest, const void *src, ulong n);
+int strncmp(const char *s1, const char *s2, ulong n);
 int query_linuxbios(void);
 int query_pcbios(void);
 int insertaddress(ulong);

--