Fixed a crash with ' exec stack not zero' message.

It was caused by a memory read from invalid (unmapped) address,
for example when gdb endianess does not match the target endianess.

adapter-mpsse.c

@@ -688,7 +688,8 @@ static void pracc_exec_write (mpsse_adapter_t *a, unsigned address)
     } else if (address == PRACC_STACK)
     {
         /* save data onto our stack */
-        a->stack [a->stack_offset++] = data;
+        offset = a->stack_offset++;
+        a->stack [offset] = data;
     } else
     {
         fprintf (stderr, "%s: error writing unexpected address %08x\n",
@@ -705,8 +706,9 @@ static void pracc_exec_write (mpsse_adapter_t *a, unsigned address)
  * supplied via EJTAG block.  Input and output data are mapped to
  * special regions in debug memory segment.  A separate stack region
  * exists for temporary storage.
+ * Return zero, when failed (stack disbalanced).
  */
-static void mpsse_exec (adapter_t *adapter, int stay_in_debug_mode,
+static int mpsse_exec (adapter_t *adapter, int stay_in_debug_mode,
     int code_len, const unsigned *code,
     int num_param_in, unsigned *param_in,
     int num_param_out, unsigned *param_out)
@@ -765,11 +767,7 @@ static void mpsse_exec (adapter_t *adapter, int stay_in_debug_mode,
     }
 done:
     /* Stack sanity check */
-    if (a->stack_offset != 0) {
-        fprintf (stderr, "%s: exec stack not zero = %d\n",
-            a->adapter.name, a->stack_offset);
-        exit (-1);
-    }
+    return (a->stack_offset == 0);
 }
 
 /*

adapter-pickit2.c

@@ -466,8 +466,9 @@ static void pracc_exec_write (pickit_adapter_t *a, unsigned address)
  * supplied via EJTAG block.  Input and output data are mapped to
  * special regions in debug memory segment.  A separate stack region
  * exists for temporary storage.
+ * Return zero, when failed (stack disbalanced).
  */
-static void pickit_exec (adapter_t *adapter, int stay_in_debug_mode,
+static int pickit_exec (adapter_t *adapter, int stay_in_debug_mode,
     int code_len, const unsigned *code,
     int num_param_in, unsigned *param_in,
     int num_param_out, unsigned *param_out)
@@ -538,11 +539,7 @@ static void pickit_exec (adapter_t *adapter, int stay_in_debug_mode,
     }
 done:
     /* Stack sanity check */
-    if (a->stack_offset != 0) {
-        fprintf (stderr, "%s: exec stack not zero = %d\n",
-            a->adapter.name, a->stack_offset);
-        exit (-1);
-    }
+    return (a->stack_offset == 0);
 }
 
 /*

adapter.h

@@ -38,7 +38,7 @@ struct _adapter_t {
     int (*cpu_stopped) (adapter_t *a);
     void (*reset_cpu) (adapter_t *a);
     void (*stop_cpu) (adapter_t *a);
-    void (*exec) (adapter_t *a, int cycle,
+    int (*exec) (adapter_t *a, int cycle,
                   int num_code_words, const unsigned *code,
                   int num_param_in, unsigned *param_in,
                   int num_param_out, unsigned *param_out);

target-ejtag.c

@@ -832,8 +832,13 @@ unsigned target_read_word (target_t *t, unsigned addr)
     };
     unsigned word;
 
-    t->adapter->exec (t->adapter, 1,
-        ARRAY_SIZE(code), code, 1, &addr, 1, &word);
+    if (! t->adapter->exec (t->adapter, 1,
+        ARRAY_SIZE(code), code, 1, &addr, 1, &word))
+    {
+        /* Exception: bad address. */
+        fprintf (stderr, "ERROR: cannot read address %08x\n", addr);
+        return 0;
+    }
     return word;
 }
 
@@ -898,8 +903,13 @@ void target_read_block (target_t *t, unsigned addr,
         param_in[0] = addr;
         param_in[1] = n;
 
-        t->adapter->exec (t->adapter, 1, ARRAY_SIZE(code), code,
-            ARRAY_SIZE(param_in), param_in, n, &data[nread]);
+        if (! t->adapter->exec (t->adapter, 1, ARRAY_SIZE(code), code,
+            ARRAY_SIZE(param_in), param_in, n, &data[nread]))
+        {
+            /* Exception: bad address. */
+            fprintf (stderr, "ERROR: cannot read address %08x\n", addr);
+            memset (&data[nread], 0, 4*n);
+        }
 
         nwords -= n;
         addr += n;
@@ -935,8 +945,11 @@ void target_write_word (target_t *t, unsigned addr, unsigned word)
 
     param_in[0] = addr;
     param_in[1] = word;
-    t->adapter->exec (t->adapter, 1, ARRAY_SIZE(code), code,
-        ARRAY_SIZE(param_in), param_in, 0, 0);
+    if (! t->adapter->exec (t->adapter, 1, ARRAY_SIZE(code), code,
+        ARRAY_SIZE(param_in), param_in, 0, 0))
+    {
+        fprintf (stderr, "ERROR: cannot write %08x to address %08x\n", word, addr);
+    }
 }
 
 /*
@@ -985,8 +998,11 @@ void target_write_block (target_t *t, unsigned addr,
     param_in[1] = addr + (nwords * sizeof(unsigned));	/* last address */
     memcpy (&param_in[2], data, nwords * sizeof(unsigned));
 
-    t->adapter->exec (t->adapter, 1, ARRAY_SIZE(code), code,
-        nwords + 2, param_in, 0, 0);
+    if (! t->adapter->exec (t->adapter, 1, ARRAY_SIZE(code), code,
+        nwords + 2, param_in, 0, 0))
+    {
+        fprintf (stderr, "ERROR: cannot write %u words to address %08x\n", nwords, addr);
+    }
 }
 
 /*