1 files changed, 89 insertions, 0 deletions
diff --git a/arch/riscv/usr/basics.c b/arch/riscv/usr/basics.c
new file mode 100644
index 0000000..4b5f289
--- /dev/null
+++ b/arch/riscv/usr/basics.c
@@ -0,0 +1,89 @@
+#include <assert.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+
+/*
+ * Returns the factorial for the given unsigned 64-bit integer.
+ *
+ * Implemented in factorial.S
+ */
+int factorial(uint64_t n);
+
+void test_factorial(void)
+{
+	assert(factorial(0) == 0);
+	assert(factorial(1) == 1);
+	assert(factorial(2) == 2);
+	assert(factorial(3) == 6);
+	assert(factorial(4) == 24);
+
+	printf("factorial:\t\tOK\n");
+}
+
+/*
+ * Returns a pointer with the same given string but reversed. Note that the
+ * string cannot be in read-only space since the reversal is done in-place.
+ *
+ * Implemented in string.S
+ */
+char * reverse_string(char *str);
+
+void test_reverse_string(void)
+{
+	assert(reverse_string(NULL) == NULL);
+	assert(reverse_string("") == "");
+
+	char s1[] = "This is a string.";
+	assert(strcmp(reverse_string(s1), ".gnirts a si sihT") == 0);
+
+	char s2[] = ".";
+	assert(strcmp(reverse_string(s2), ".") == 0);
+
+	printf("reverse_string:\t\tOK\n");
+}
+
+/*
+ * Returns true if the given string is a palindrome, false otherwise.
+ *
+ * Implemented in string.S
+ */
+bool is_palindrome(char *str);
+
+void test_is_palindrome(void)
+{
+	assert(is_palindrome(NULL) == 0);
+	assert(is_palindrome("") == 0);
+	assert(is_palindrome("aba") == 1);
+	assert(is_palindrome("aaa") == 1);
+	assert(is_palindrome("This is a a si sihT") == 1);
+
+	printf("is_palindrome:\t\tOK\n");
+}
+
+/*
+ * This function computes the following: ((a + b) * b) + b. Don't try to make
+ * sense of it, that's the computation I ended up while messing with RISC-V
+ * floating point instructions. Anyways, with this in mind, it will return if
+ * the computed value is greater than 10.
+ *
+ * Implemented in float.S
+ */
+bool greater_than_ten(double a, uint64_t b);
+
+void test_greater_than_ten(void)
+{
+	assert(!greater_than_ten(2.3, 1)); // 4.3
+	assert(greater_than_ten(2.3, 2));  // 10.6
+
+	printf("greater_than_ten:\tOK\n");
+}
+
+int main()
+{
+	test_factorial();
+	test_reverse_string();
+	test_is_palindrome();
+	test_greater_than_ten();
+}