From fd2fc0e02b4a879daca8e4a2939758f6f16b620a Mon Sep 17 00:00:00 2001
From: TomW <TomW@localhost>
Date: Sun, 21 Jun 2015 14:52:53 +0100
Subject: [PATCH] Implemented serial scratch register. Serial IER register only
 4 bits wide.

---
 src/serial.c | 8 +++++++-
 src/serial.h | 1 +
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/serial.c b/src/serial.c
index e294039..fb5c458 100644
--- a/src/serial.c
+++ b/src/serial.c
@@ -110,7 +110,7 @@ void serial_write(uint16_t addr, uint8_t val, void *p)
                         serial->dlab2 = val;
                         return;
                 }
-                serial->ier = val;
+                serial->ier = val & 0xf;
                 serial_update_ints(serial);
                 break;
                 case 3:
@@ -160,6 +160,9 @@ void serial_write(uint16_t addr, uint8_t val, void *p)
                         serial->int_status |= SERIAL_INT_MSR;
                 serial_update_ints(serial);
                 break;
+                case 7:
+                serial->scratch = val;
+                break;
         }
 }
 
@@ -221,6 +224,9 @@ uint8_t serial_read(uint16_t addr, void *p)
                 serial->int_status &= ~SERIAL_INT_MSR;
                 serial_update_ints(serial);
                 break;
+                case 7:
+                temp = serial->scratch;
+                break;
         }
 //        pclog("%02X\n",temp);
         return temp;
diff --git a/src/serial.h b/src/serial.h
index e57e066..469c29b 100644
--- a/src/serial.h
+++ b/src/serial.h
@@ -14,6 +14,7 @@ typedef struct
         uint8_t dlab1,dlab2;
         uint8_t dat;
         uint8_t int_status;
+        uint8_t scratch;
         
         int irq;