🆕 malloc 、printf

user/libs/libc/stdlib.c

@@ -0,0 +1,45 @@
+#include <libc/unistd.h>
+#include <libc/stdlib.h>
+
+int abs(int i)
+{
+    return i < 0 ? -i : i;
+}
+
+long labs(long i)
+{
+    return i < 0 ? -i : i;
+}
+
+long long llabs(long long i)
+{
+    return i < 0 ? -i : i;
+}
+
+int atoi(const char *str)
+{
+    int n = 0, neg = 0;
+
+    while (isspace(*str))
+    {
+        str++;
+    }
+
+    switch (*str)
+    {
+    case '-':
+        neg = 1;
+        break;
+    case '+':
+        str++;
+        break;
+    }
+
+    /* Compute n as a negative number to avoid overflow on INT_MIN */
+    while (isdigit(*str))
+    {
+        n = 10 * n - (*str++ - '0');
+    }
+
+    return neg ? n : -n;
+}