From 954696728cf4b6a575c3a59517dd677ec6332f26 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Lov=C3=A9n?= <thomasloven@gmail.com>
Date: Sun, 3 Dec 2017 22:28:58 +0100
Subject: [PATCH] Add memory copy and move functions. Required by gcc, and
 we'll also use them soon

---
 src/kernel/include/memory.h |  9 ++++++++
 src/kernel/memory/string.c  | 43 +++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 src/kernel/memory/string.c

diff --git a/src/kernel/include/memory.h b/src/kernel/include/memory.h
index 8af8e45..17cb7a4 100644
--- a/src/kernel/include/memory.h
+++ b/src/kernel/include/memory.h
@@ -21,3 +21,12 @@
 
 #define PAGE_SIZE       0x1000
 #define ENTRIES_PER_PT  512
+
+#ifndef __ASSEMBLER__
+#include <stddef.h>
+void *memcpy(void *dst, const void *src, size_t n);
+void *memset(void *s, int c, size_t n);
+void *memmove(void *dest, const void *src, size_t n);
+int memcmp(const void *s1, const void *s2, size_t n);
+size_t strlen(const char *s);
+#endif
diff --git a/src/kernel/memory/string.c b/src/kernel/memory/string.c
new file mode 100644
index 0000000..7625e46
--- /dev/null
+++ b/src/kernel/memory/string.c
@@ -0,0 +1,43 @@
+#include <memory.h>
+#include <stdint.h>
+#include <stddef.h>
+
+void *memcpy(void *dst, const void *src, size_t n)
+{
+  char *dp = dst;
+  const char *sp = src;
+  while(n--) *dp++ = *sp++;
+  return dst;
+}
+
+void *memset(void *s, int c, size_t n)
+{
+  unsigned char *p = s;
+  while(n--) *p++ = (unsigned char)c;
+  return s;
+}
+
+void *memmove(void *dest, const void *src, size_t n)
+{
+  // Since our memcpy implementation copies one char* at a time, this is safe
+  memcpy(dest, src, n);
+  return dest;
+}
+
+int memcmp(const void *s1, const void *s2, size_t n)
+{
+  const unsigned char *p1 = s1, *p2 = s2;
+  for(; n--; p1++, p2++)
+  {
+    if(*p1 != *p2)
+      return *p1 - *p2;
+  }
+  return 0;
+}
+
+size_t strlen(const char *s)
+{
+  size_t len = 0;
+  while(*s++) len++;
+  return len;
+}