From c9750e4834605b59fa30f0e00685229d5531ac3d Mon Sep 17 00:00:00 2001
From: Ali Mashtizadeh <mashti@cs.stanford.edu>
Date: Sun, 13 Jul 2014 13:36:43 -0700
Subject: [PATCH] Basic debugger support over serial

---
 sys/SConscript       |  1 +
 sys/amd64/debug.c    |  2 +-
 sys/dev/console.c    | 26 ++++++++++++++++++++++++--
 sys/dev/console.h    |  2 ++
 sys/include/kdebug.h | 13 +++++++++++++
 sys/kern/debug.c     | 18 ++++++++++++++----
 6 files changed, 55 insertions(+), 7 deletions(-)
 create mode 100644 sys/include/kdebug.h

diff --git a/sys/SConscript b/sys/SConscript
index b2eca15..f7d9ec6 100644
--- a/sys/SConscript
+++ b/sys/SConscript
@@ -11,6 +11,7 @@ src_amd64 = [
     "amd64/multiboot.S",
     "amd64/mbentry.c",
     # AMD64
+    "amd64/debug.c",
     "amd64/trap.c",
     "amd64/trapentry.S",
     "amd64/machine.c",
diff --git a/sys/amd64/debug.c b/sys/amd64/debug.c
index bbba551..b560df3 100644
--- a/sys/amd64/debug.c
+++ b/sys/amd64/debug.c
@@ -3,7 +3,7 @@
 
 #include <kassert.h>
 #include <kconfig.h>
-//#include <kdebug.h>
+#include <kdebug.h>
 #include <mp.h>
 
 #include "trap.h"
diff --git a/sys/dev/console.c b/sys/dev/console.c
index f66b34d..6b82e23 100644
--- a/sys/dev/console.c
+++ b/sys/dev/console.c
@@ -29,9 +29,31 @@ Console_LateInit()
     Serial_LateInit();
 }
 
-void
-Console_Getc(char ch)
+char
+Console_Getc()
 {
+    return Serial_Getc();
+}
+
+void
+Console_Gets(char *str, size_t n)
+{
+    int i;
+
+    for (i = 0; i < (n - 1); i++)
+    {
+	char ch = Console_Getc();
+	if (ch == '\r')
+	{
+	    Console_Putc('\n');
+	    str[i] = '\0';
+	    return;
+	}
+	Console_Putc(ch);
+	str[i] = ch;
+    }
+
+    str[i+1] = '\0';
 }
 
 void
diff --git a/sys/dev/console.h b/sys/dev/console.h
index b7511ca..174eba6 100644
--- a/sys/dev/console.h
+++ b/sys/dev/console.h
@@ -3,6 +3,8 @@
 #define __CONSOLE_H__
 
 void Console_Init();
+char Console_Getc();
+void Console_Gets(char *str, size_t n);
 void Console_Putc(char ch);
 void Console_Puts(const char *str);
 
diff --git a/sys/include/kdebug.h b/sys/include/kdebug.h
new file mode 100644
index 0000000..854e4a4
--- /dev/null
+++ b/sys/include/kdebug.h
@@ -0,0 +1,13 @@
+
+#ifndef __KDEBUG_H__
+#define __KDEBUG_H__
+
+// Platform Functions
+void Debug_Registers(int argc, const char *argv[]);
+
+// Generic Functions
+void Debug_Dump(int argc, const char *argv[]);
+void Debug_Prompt();
+
+#endif /* __KDEBUG_H__ */
+
diff --git a/sys/kern/debug.c b/sys/kern/debug.c
index d1f32c6..9832754 100644
--- a/sys/kern/debug.c
+++ b/sys/kern/debug.c
@@ -18,6 +18,9 @@
 #include <stdint.h>
 
 #include <kassert.h>
+#include <kdebug.h>
+
+#include "../dev/console.h"
 
 void
 Debug_PrintHex(const char *data, size_t length, off_t off, size_t limit)
@@ -75,16 +78,23 @@ Debug_Dump(int argc, const char *argv[])
 {
 }
 
+#define DEBUG_MAX_LINE		128
+
 void
 Debug_Prompt()
 {
+    char buf[DEBUG_MAX_LINE];
     kprintf("Entered Debugger!\n");
 
-    kprintf("> ");
-    // read input
+    while (1) {
+	kprintf("> ");
 
-    // parse input
+	// read input
+	Console_Gets(&buf, DEBUG_MAX_LINE);
 
-    // execute command
+	// parse input
+
+	// execute command
+    }
 }