Initial commit

x86 kernel that prints a hello world message to com1

6 files changed, 91 insertions, 0 deletions

diff --git a/lib/memcpy.c b/lib/memcpy.c
new file mode 100644
index 0000000..c648501
--- /dev/null
+++ b/lib/memcpy.c
@@ -0,0 +1,20 @@
+/**
+ * The  memcpy()  function copies n bytes from memory area src to memory area dest.  The memory areas must not overlap.
+ * @param dest
+ * @param src
+ * @param n
+ * @return
+ */
+void *
+memcpy(void *restrict dest, const void *restrict src, unsigned n)
+{
+  char *pDest = (char *)dest;
+  const char *pSrc = (const char *)src;
+
+  while (n) {
+    *(pDest++) = *(pSrc++);
+    --n;
+  }
+
+  return dest;
+}
\ No newline at end of file
diff --git a/lib/memset.c b/lib/memset.c
new file mode 100644
index 0000000..442a305
--- /dev/null
+++ b/lib/memset.c
@@ -0,0 +1,14 @@
+/**
+ * The memset() function fills the first n bytes of the memory area pointed to by s with the constant byte c.
+ * @param s
+ * @param c
+ * @param n
+ * @return
+ */
+void *
+memset(void *s, char c, unsigned n)
+{
+  char *pDest = (char *)s;
+  for (unsigned i = 0; i < n; ++i) pDest[i] = c;
+  return s;
+}
\ No newline at end of file
diff --git a/lib/stdio.h b/lib/stdio.h
new file mode 100644
index 0000000..cf3a33f
--- /dev/null
+++ b/lib/stdio.h
@@ -0,0 +1,3 @@
+#pragma once
+
+int printf(const char *restrict format, ...);
diff --git a/lib/stdio/printf.c b/lib/stdio/printf.c
new file mode 100644
index 0000000..f6b8ef6
--- /dev/null
+++ b/lib/stdio/printf.c
@@ -0,0 +1,38 @@
+#include <stdarg.h>
+#include <stdio.h>
+
+#include <devices/uart_16550.h>
+
+int
+printf(const char *restrict format, ...)
+{
+  int written = 0;
+  va_list params;
+  va_start(params, format);
+
+  int s = 0;
+  int l = 0;
+  for (int i = 0; format[i] != '\0'; ++i) {
+    if (format[i] == '%') {
+      written += uart_puts(COM1, &format[s], l);
+      s = i + 2;
+      ++i;
+
+      switch (format[i]) {
+      case 's':
+        written += uart_puts(COM1, va_arg(params, const char *), -1);
+        break;
+      }
+
+      l = 0;
+    }
+
+    else
+      ++l;
+  }
+
+  if (l > 0) written += uart_puts(COM1, &format[s], l);
+
+  va_end(params);
+  return written;
+}
diff --git a/lib/string.h b/lib/string.h
new file mode 100644
index 0000000..361d308
--- /dev/null
+++ b/lib/string.h
@@ -0,0 +1,3 @@
+#pragma once
+
+char *itoa(char *p, unsigned x);
diff --git a/lib/string/itoa.c b/lib/string/itoa.c
new file mode 100644
index 0000000..5eefb37
--- /dev/null
+++ b/lib/string/itoa.c
@@ -0,0 +1,13 @@
+#include "string.h"
+
+char *
+itoa(char *p, unsigned x)
+{
+  p += 3 * sizeof(int);
+  *--p = 0;
+  do {
+    *--p = '0' + x % 10;
+    x /= 10;
+  } while (x);
+  return p;
+}