1 files changed, 57 insertions, 0 deletions
diff --git a/lib/blkmov.c b/lib/blkmov.c
new file mode 100644
index 0000000..6423810
--- /dev/null
+++ b/lib/blkmov.c
@@ -0,0 +1,57 @@
+/**
+** @file	blkmov.c
+**
+** @author	Numerous CSCI-452 classes
+**
+** @brief	C implementations of common library functions
+*/
+
+#ifndef BLKMOV_SRC_INC
+#define BLKMOV_SRC_INC
+
+#include <common.h>
+
+#include <lib.h>
+
+/**
+** blkmov(dst,src,len)
+**
+** Copy a word-aligned block from src to dst. Deals with overlapping
+** buffers.
+**
+** @param dst   Destination buffer
+** @param src   Source buffer
+** @param len   Buffer size (in bytes)
+*/
+void blkmov(void *dst, const void *src, register uint32_t len)
+{
+	// verify that the addresses are aligned and
+	// the length is a multiple of four bytes
+	if ((((uint32_t)dst) & 0x3) != 0 || (((uint32_t)src) & 0x3) != 0 ||
+		(len & 0x3) != 0) {
+		// something isn't aligned, so just use memmove()
+		memmove(dst, src, len);
+		return;
+	}
+
+	// everything is nicely aligned, so off we go
+	register uint32_t *dest = dst;
+	register const uint32_t *source = src;
+
+	// now copying 32-bit values
+	len /= 4;
+
+	if (source < dest && (source + len) > dest) {
+		source += len;
+		dest += len;
+		while (len-- > 0) {
+			*--dest = *--source;
+		}
+	} else {
+		while (len--) {
+			*dest++ = *source++;
+		}
+	}
+}
+
+#endif