From d94b024b73aeca06de417e0fd3c502495312a8b2 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Sat, 7 Dec 2019 13:40:28 +0100
Subject: Added userspace libc and began userspace based shell

---
 src/kernel/lib/stdlib/atoi.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 src/kernel/lib/stdlib/atoi.c

(limited to 'src/kernel/lib/stdlib/atoi.c')

diff --git a/src/kernel/lib/stdlib/atoi.c b/src/kernel/lib/stdlib/atoi.c
new file mode 100644
index 0000000..4044972
--- /dev/null
+++ b/src/kernel/lib/stdlib/atoi.c
@@ -0,0 +1,24 @@
+#include <kernel/lib/math.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <kernel/lib/string.h>
+
+int atoi(char *str)
+{
+    size_t s_str = strlen(str);
+    if (!s_str) return 0;
+
+    uint8_t negative = 0;
+    if (str[0] == '-') negative = 1;
+
+    size_t i = 0;
+    if (negative) i++;
+
+    int ret = 0;
+    for (; i < s_str; i++) {
+        ret += (str[i] - '0') * pow(10, (s_str - i) - 1);
+    }
+
+    if (negative) ret *= -1;
+    return ret;
+}
\ No newline at end of file
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