From 5a25f38de6d3e2506838191c55af94cb56c9f641 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Sun, 19 Apr 2020 10:06:21 -0700
Subject: feat: quality of life scripts to initialize make rules

---
 sys/libc/string.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 sys/libc/string.c

(limited to 'sys/libc/string.c')

diff --git a/sys/libc/string.c b/sys/libc/string.c
new file mode 100644
index 0000000..8fcdfd2
--- /dev/null
+++ b/sys/libc/string.c
@@ -0,0 +1,80 @@
+#include <u.h>
+#include <libc.h>
+
+void*
+memcopy(void* dst, void* src, intptr n)
+{
+    byte *e, *s, *d; 
+
+    d = dst;
+    e = d + n;
+    for (s = src ; d != e; ++s, ++d) {
+        *d = *s;
+    }
+
+    return dst;
+}
+
+void*
+memmove(void* dst, void* src, intptr n)
+{
+    byte *e, *s, *d;
+    s = src;
+    d = dst;
+
+    if (d < s) {
+        e = d + n;
+        for (; d != e; ++s, ++d) 
+            *d = *s;
+
+    } else {
+        e = d;
+        d += n;
+        s += n;
+        for (; d != e; --s, --d)
+            d[-1] = s[-1];
+    }
+
+    return dst;
+}
+
+void*
+memset(void* buf, int val, intptr n)
+{
+    byte *b, *e;
+    b = buf;
+    e = b + n;
+    for (; b != e; b++) {
+        *b = (byte)val;
+    }
+
+    return buf;
+}
+
+int
+memcmp(void* lhs, void* rhs, intptr n)
+{
+    byte *bl, *br, *e;
+
+    br = rhs;
+    e  = br + n;
+    for (bl = lhs; br != e; ++bl, ++br) {
+        if (*bl < *br)
+            return -1;
+        else if (*bl > *br) 
+            return 1;
+    }
+
+    return 0;
+}
+
+int
+strlen(byte* s)
+{
+    byte* b;
+    for (b = s; *b; b++) {
+        ;
+    }
+
+    return b - s;
+}
-- 
cgit v1.2.1