[libc] add implementation of atoull

2 files changed, 19 insertions, 0 deletions

diff --git a/include/stdlib.h b/include/stdlib.h
index c31dd9c1..a602ccb2 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -34,6 +34,7 @@ int atoi(const char *num);
 unsigned int atoui(const char *num);
 long atol(const char *num);
 unsigned long atoul(const char *num);
+unsigned long long atoull(const char *num);
 
 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
 #define MAX(a, b) (((a) > (b)) ? (a) : (b))
diff --git a/lib/libc/atoi.c b/lib/libc/atoi.c
index 809e1830..f5610835 100644
--- a/lib/libc/atoi.c
+++ b/lib/libc/atoi.c
@@ -103,3 +103,21 @@ unsigned long atoul(const char *num)
 	return value;
 }
 
+unsigned long long atoull(const char *num)
+{
+	unsigned long long value = 0;
+	if (num[0] == '0' && num[1] == 'x') {
+		// hex
+		num += 2;
+		while (*num && isxdigit(*num))
+			value = value * 16 + hexval(*num++);
+	} else {
+		// decimal
+		while (*num && isdigit(*num))
+			value = value * 10 + *num++  - '0';
+	}
+
+	return value;
+}
+
+