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From 0f2c7ca446063be6b193fbf870d38c0af19e15c5 Mon Sep 17 00:00:00 2001
From: Jaxson Han <jaxson.han@arm.com>
Date: Tue, 28 Dec 2021 17:28:25 +0800
Subject: [PATCH] common: Add essential libc functions
The libfdt uses some of the libc functions, e.g. memcmp, memmove,
strlen .etc. Add them in lib.c.
The code is copied from TF-A (v2.5) [1] project, which is under the
terms of BSD license. It is the same with boot-wrapper.
[1]: https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git
Issue-Id: SCM-3814
Upstream-Status: Inappropriate [other]
Implementation pending further discussion
Signed-off-by: Jaxson Han <jaxson.han@arm.com>
Change-Id: If3b55b00afa8694c7522df989a41e0b38eda1d38
---
common/lib.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 70 insertions(+), 1 deletion(-)
diff --git a/common/lib.c b/common/lib.c
index fcf5f69..0be1c4a 100644
--- a/common/lib.c
+++ b/common/lib.c
@@ -32,4 +32,73 @@ void *memset(void *s, int c, size_t n)
return s;
}
-/* TODO: memmove and memcmp could also be called */
+int memcmp(const void *s1, const void *s2, size_t len)
+{
+ const unsigned char *s = s1;
+ const unsigned char *d = s2;
+ unsigned char sc;
+ unsigned char dc;
+
+ while (len--) {
+ sc = *s++;
+ dc = *d++;
+ if (sc - dc)
+ return (sc - dc);
+ }
+
+ return 0;
+}
+
+void *memmove(void *dst, const void *src, size_t len)
+{
+ if ((size_t)dst - (size_t)src >= len) {
+ /* destination not in source data, so can safely use memcpy */
+ return memcpy(dst, src, len);
+ } else {
+ /* copy backwards... */
+ const char *end = dst;
+ const char *s = (const char *)src + len;
+ char *d = (char *)dst + len;
+ while (d != end)
+ *--d = *--s;
+ }
+ return dst;
+}
+
+void *memchr(const void *src, int c, size_t len)
+{
+ const unsigned char *s = src;
+
+ while (len--) {
+ if (*s == (unsigned char)c)
+ return (void *) s;
+ s++;
+ }
+
+ return NULL;
+}
+
+char *strrchr(const char *p, int ch)
+{
+ char *save;
+ char c;
+
+ c = ch;
+ for (save = NULL;; ++p) {
+ if (*p == c)
+ save = (char *)p;
+ if (*p == '\0')
+ return (save);
+ }
+ /* NOTREACHED */
+}
+
+size_t strlen(const char *s)
+{
+ const char *cursor = s;
+
+ while (*cursor)
+ cursor++;
+
+ return cursor - s;
+}
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