Added rotating buffers

2 files changed, 20 insertions, 0 deletions

diff --git a/include/lib/mem.h b/include/lib/mem.h
index eff6445..04056f7 100644
--- a/include/lib/mem.h
+++ b/include/lib/mem.h
@@ -12,9 +12,16 @@ struct MemTab {
 	void* data;
 } __attribute__((packed));
 
+struct RotBuffer {
+	void* base;
+	unsigned int size;
+	unsigned int offset;
+};
+
 void memset(unsigned char* dest, unsigned char value, unsigned int n);
 void memcpy(unsigned char* src, unsigned char* dest, unsigned int n);
 unsigned char memcmp(unsigned char* a, unsigned char* b, unsigned int n);
+void memcpyrot(unsigned char* src, struct RotBuffer* rb, unsigned int n);
 
 void memshow32(unsigned long* addr, unsigned int n);
 void memset32(unsigned long* dest, unsigned long value, unsigned int n);
diff --git a/src/lib/mem.c b/src/lib/mem.c
index 91fed94..dc915e6 100644
--- a/src/lib/mem.c
+++ b/src/lib/mem.c
@@ -1,6 +1,19 @@
 #include <drivers/uart.h>
 #include <lib/mem.h>
 
+void memcpyrot(unsigned char* src, struct RotBuffer* rb, unsigned int n)
+{
+	if (n > rb->size)
+		return;
+	unsigned char* addr = rb->base + rb->offset;
+	for (unsigned int i = 0; i < n; i++) {
+		if (addr >= (unsigned char*)(rb->base + rb->size))
+			addr = rb->base;
+		*addr = src[i];
+		addr++;
+	}
+}
+
 void memshow32(unsigned long* addr, unsigned int n)
 {
 	for(unsigned int i = 0; i < n; i++) {