minor changes and some notes on keyboard driver

1 files changed, 51 insertions, 0 deletions

diff --git a/README.md b/README.md
index f3be90c..0bd2a18 100644
--- a/README.md
+++ b/README.md
@@ -116,6 +116,57 @@ REFERENCES
 MY NOTES BELOW THIS LINE
 ========================
 
+Keyboard Driver
+---------------
+
+//some thoughts on redesign of the keyboard driver
+//use uint8_t for proc_pos and buff_pos and a BUF_SIZE of 256 for auto wrap!?
+
+// kb input ringbuffer
+#define BUF_SIZE 256
+kb_scancode kb_buff[BUF_SIZE];
+
+buff_pos=0;
+proc_pos=0;
+buffered=0;
+
+void kb_irq()
+{
+    cli
+
+    //we get one interrupt for EACH scancode!
+    kb_scancode val=get_scancode();
+
+    // think about race condition if called while inside kb_proc();
+    if(buffered+1<BUF_SIZE)
+    {
+	kb_buff[buff_pos]=val; 
+	buff_pos++;	    
+	buffered++;
+    }
+    else
+    {
+	//kb ring buffer is full;
+    }
+    sti
+
+}
+
+
+void kb_proc()
+{
+    if(proc_pos!=buff_pos)
+    {
+	kb_scancode val=kb_buff[proc_pos];
+
+	proc_pos++;
+	buffered--;
+
+	stdin(scancode_to_char(val));
+	
+    }
+}
+
 Linux Startup x86
 -----------------
 ~ ontogeny recapitulates phylogeny ~