add support for simple character input via the system console

dev/alpha_access.h:
    -  use our standard types instead of this extra typedef
    -  advance the ALPHA_ACCESS version since the interface
    has changed.  *this means you need a new console binary*
    -  shuffle a couple things around to pack the data structure
    a bit better
    -  add a placeholder for character input
dev/alpha_console.cc:
    Clean up the read code path a bit and add support for character
    input via the console

    Clean up the write path and use a switch instead of a bunch of
    if statements

--HG--
extra : convert_revision : a1a5bc8fed9ec9c4c46548fdf79604661668b81a

1 files changed, 10 insertions, 2 deletions

diff --git a/dev/console.hh b/dev/console.hh
index f443afe4f..9913fe379 100644
--- a/dev/console.hh
+++ b/dev/console.hh
@@ -109,9 +109,17 @@ class SimConsole : public SimObject
     // OS interface
 
     // Get a character from the console.
-    // return of -1 means there is no character pending.
+    // the return value corresponds to the console GETC return value:
+    // retval<63:61>
+    //     000: success: character received
+    //     001: success: character received, more pending
+    //     100: failure: no character ready
+    //     110: failure: character received with error
+    //     111: failure: character received with error, more pending
+    // retval<31:0>
+    //     character read from console
     // Interrupts are cleared when the buffer is empty.
-    int in();
+    uint64_t in();
 
     // Send a character to the console
     void out(char c, bool raise_int = true);