mac_via: fix up adb_via_receive() trace events

The use of the post-increment operator on adb_data_in_index meant that the
trace-event was accidentally displaying the next byte in the incoming ADB
data buffer rather than the current byte.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20210311100505.22596-3-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

1 files changed, 24 insertions, 17 deletions

diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c
index ca2f939dd5..0a25de577c 100644
--- a/hw/misc/mac_via.c
+++ b/hw/misc/mac_via.c
@@ -816,33 +816,37 @@ static void adb_via_receive(MacVIAState *s, int state, uint8_t *data)
         switch (s->adb_data_in_index) {
         case 0:
             /* First EVEN byte: vADBInt indicates bus timeout */
-            trace_via1_adb_receive(state == ADB_STATE_EVEN ? "EVEN" : " ODD",
-                                   *data, (ms->b & VIA1B_vADBInt) ? "+" : "-",
-                                   adb_bus->status, s->adb_data_in_index,
-                                   s->adb_data_in_size);
-
-            *data = s->adb_data_in[s->adb_data_in_index++];
+            *data = s->adb_data_in[s->adb_data_in_index];
             if (adb_bus->status & ADB_STATUS_BUSTIMEOUT) {
                 ms->b &= ~VIA1B_vADBInt;
             } else {
                 ms->b |= VIA1B_vADBInt;
             }
-            break;
 
-        case 1:
-            /* First ODD byte: vADBInt indicates SRQ */
             trace_via1_adb_receive(state == ADB_STATE_EVEN ? "EVEN" : " ODD",
                                    *data, (ms->b & VIA1B_vADBInt) ? "+" : "-",
                                    adb_bus->status, s->adb_data_in_index,
                                    s->adb_data_in_size);
 
-            *data = s->adb_data_in[s->adb_data_in_index++];
+            s->adb_data_in_index++;
+            break;
+
+        case 1:
+            /* First ODD byte: vADBInt indicates SRQ */
+            *data = s->adb_data_in[s->adb_data_in_index];
             pending = adb_bus->pending & ~(1 << (s->adb_autopoll_cmd >> 4));
             if (pending) {
                 ms->b &= ~VIA1B_vADBInt;
             } else {
                 ms->b |= VIA1B_vADBInt;
             }
+
+            trace_via1_adb_receive(state == ADB_STATE_EVEN ? "EVEN" : " ODD",
+                                   *data, (ms->b & VIA1B_vADBInt) ? "+" : "-",
+                                   adb_bus->status, s->adb_data_in_index,
+                                   s->adb_data_in_size);
+
+            s->adb_data_in_index++;
             break;
 
         default:
@@ -852,14 +856,9 @@ static void adb_via_receive(MacVIAState *s, int state, uint8_t *data)
              * end of the poll reply, so provide these extra bytes below to
              * keep it happy
              */
-            trace_via1_adb_receive(state == ADB_STATE_EVEN ? "EVEN" : " ODD",
-                                   *data, (ms->b & VIA1B_vADBInt) ? "+" : "-",
-                                   adb_bus->status, s->adb_data_in_index,
-                                   s->adb_data_in_size);
-
             if (s->adb_data_in_index < s->adb_data_in_size) {
                 /* Next data byte */
-                *data = s->adb_data_in[s->adb_data_in_index++];
+                *data = s->adb_data_in[s->adb_data_in_index];
                 ms->b |= VIA1B_vADBInt;
             } else if (s->adb_data_in_index == s->adb_data_in_size) {
                 if (adb_bus->status & ADB_STATUS_BUSTIMEOUT) {
@@ -869,7 +868,6 @@ static void adb_via_receive(MacVIAState *s, int state, uint8_t *data)
                     /* Return 0x0 after reply */
                     *data = 0;
                 }
-                s->adb_data_in_index++;
                 ms->b &= ~VIA1B_vADBInt;
             } else {
                 /* Bus timeout (no more data) */
@@ -878,6 +876,15 @@ static void adb_via_receive(MacVIAState *s, int state, uint8_t *data)
                 adb_bus->status = 0;
                 adb_autopoll_unblock(adb_bus);
             }
+
+            trace_via1_adb_receive(state == ADB_STATE_EVEN ? "EVEN" : " ODD",
+                                   *data, (ms->b & VIA1B_vADBInt) ? "+" : "-",
+                                   adb_bus->status, s->adb_data_in_index,
+                                   s->adb_data_in_size);
+
+            if (s->adb_data_in_index <= s->adb_data_in_size) {
+                s->adb_data_in_index++;
+            }
             break;
         }