diff --git a/Library/Convert.c b/Library/Convert.c
index c59edbcb..f296207b 100644
--- a/Library/Convert.c
+++ b/Library/Convert.c
@@ -1,6 +1,7 @@
 #include <convert.h>
 
 #include <memory.hpp>
+#include <limits.h>
 #include <debug.h>
 
 // TODO: Replace mem* with assembly code
@@ -451,6 +452,96 @@ char *strdup(const char *String)
     return OutBuffer;
 }
 
+int isalpha(int c)
+{
+    return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
+}
+
+int isupper(int c)
+{
+    return (c >= 'A' && c <= 'Z');
+}
+
+long int strtol(const char *str, char **endptr, int base)
+{
+    const char *s;
+    long acc, cutoff;
+    int c;
+    int neg, any, cutlim;
+
+    s = str;
+    do
+    {
+        c = *s++;
+    } while (isspace(c));
+    if (c == '-')
+    {
+        neg = 1;
+        c = *s++;
+    }
+    else
+    {
+        neg = 0;
+        if (c == '+')
+            c = *s++;
+    }
+    if ((base == 0 || base == 16) && c == '0' && (*s == 'x' || *s == 'X'))
+    {
+        c = s[1];
+        s += 2;
+        base = 16;
+    }
+    if (base == 0)
+        base = c == '0' ? 8 : 10;
+
+    cutoff = neg ? LONG_MIN : LONG_MAX;
+    cutlim = cutoff % base;
+    cutoff /= base;
+    for (acc = 0, any = 0;; c = *s++)
+    {
+        if (isdigit(c))
+            c -= '0';
+        else if (isalpha(c))
+            c -= isupper(c) ? 'A' - 10 : 'a' - 10;
+        else
+            break;
+        if (c >= base)
+            break;
+        if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
+            any = -1;
+        else
+        {
+            any = 1;
+            acc *= base;
+            acc += c;
+        }
+    }
+    if (any < 0)
+    {
+        acc = neg ? LONG_MIN : LONG_MAX;
+    }
+    else if (neg)
+        acc = -acc;
+    if (endptr != 0)
+        *endptr = (char *)(any ? s - 1 : str);
+    return (acc);
+
+    // long int result = 0;
+    // int sign = 1;
+    // if (*str == '-')
+    // {
+    //     sign = -1;
+    //     str++;
+    // }
+    // while (*str)
+    // {
+    //     result *= base;
+    //     result += *str - '0';
+    //     str++;
+    // }
+    // return result * sign;
+}
+
 int isdigit(int c)
 {
     return c >= '0' && c <= '9';
diff --git a/include/convert.h b/include/convert.h
index dcc290a1..ec887912 100644
--- a/include/convert.h
+++ b/include/convert.h
@@ -8,6 +8,8 @@ extern "C"
     int isdigit(int c);
     int isspace(int c);
     int isempty(char *str);
+    int isalpha(int c);
+    int isupper(int c);
     unsigned int isdelim(char c, char *delim);
     int abs(int i);
     void swap(char *x, char *y);
@@ -40,6 +42,7 @@ extern "C"
     int strncasecmp(const char *lhs, const char *rhs, long unsigned int Count);
     int strcasecmp(const char *lhs, const char *rhs);
     char *strtok(char *src, const char *delim);
+    long int strtol(const char *str, char **endptr, int base);
 
     void *__memcpy_chk(void *dest, const void *src, size_t len, size_t slen);
     void *__memset_chk(void *dest, int val, size_t len, size_t slen);