From 0481aa08e5a22173f1e4a5a5f8ba01756085b9d3 Mon Sep 17 00:00:00 2001
From: tmk <hasu@tmk-kbd.com>
Date: Mon, 2 Mar 2020 01:48:11 +0900
Subject: [PATCH] ibmpc: Check buffer full and error code FF

---
 tmk_core/protocol/ibmpc.c | 22 ++++++++++++++--------
 tmk_core/protocol/ibmpc.h |  1 +
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/tmk_core/protocol/ibmpc.c b/tmk_core/protocol/ibmpc.c
index 9553e7ee..8e195e94 100644
--- a/tmk_core/protocol/ibmpc.c
+++ b/tmk_core/protocol/ibmpc.c
@@ -268,8 +268,7 @@ ISR(IBMPC_INT_VECT)
             break;
         case 0b11000000:
             // XT_Clone-done
-            recv_data = recv_data<<8;
-            recv_data |= (isr_state>>8) & 0xFF;
+            isr_state = isr_state>>8;
             goto DONE;
             break;
         case 0b10100000:    // ^2
@@ -284,8 +283,7 @@ ISR(IBMPC_INT_VECT)
                     goto NEXT;
                 } else {
                     // no stop bit: XT_IBM-done
-                    recv_data = recv_data<<8;
-                    recv_data |= (isr_state>>8) & 0xFF;
+                    isr_state = isr_state>>8;
                     goto DONE;
                 }
              }
@@ -294,10 +292,9 @@ ISR(IBMPC_INT_VECT)
         case 0b10010000:
         case 0b01010000:
         case 0b11010000:
-            // TODO: parity check?
             // AT-done
-            recv_data = recv_data<<8;
-            recv_data |= (isr_state>>6) & 0xFF;
+            // TODO: parity check?
+            isr_state = isr_state>>6;
             goto DONE;
             break;
         case 0b01100000:
@@ -318,7 +315,16 @@ ERROR:
     recv_data = 0xFF00; // clear data and scancode of error 0x00
     return;
 DONE:
-    // TODO: process error code: 0x00(AT), 0xFF(XT) in particular
+    if ((isr_state & 0x00FF) == 0x00FF) {
+        // receive error code 0xFF
+        ibmpc_error = IBMPC_ERR_FF;
+    }
+    if ((recv_data & 0xFF00) != 0xFF00) {
+        // buffer full and overwritten
+        ibmpc_error = IBMPC_ERR_FULL;
+    }
+    recv_data = recv_data<<8;
+    recv_data |= isr_state & 0xFF;
     isr_state = 0x8000;  // clear to next data
 NEXT:
     return;
diff --git a/tmk_core/protocol/ibmpc.h b/tmk_core/protocol/ibmpc.h
index 18da8f4c..602a43f3 100644
--- a/tmk_core/protocol/ibmpc.h
+++ b/tmk_core/protocol/ibmpc.h
@@ -80,6 +80,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #define IBMPC_ERR_TIMEOUT     0x20
 #define IBMPC_ERR_FULL        0x40
 #define IBMPC_ERR_ILLEGAL     0x80
+#define IBMPC_ERR_FF          0xFF
 
 #define IBMPC_LED_SCROLL_LOCK 0
 #define IBMPC_LED_NUM_LOCK    1
-- 
2.46.2