Fix how 'trace.py --max-tstates' counts T-states

skoolkid · Mar 31, 2024 · d1b8e3e · d1b8e3e
1 parent ce3f96a
commit d1b8e3e
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Showing 4 changed files with 25 additions and 15 deletions.
diff --git a/c/csimulator.c b/c/csimulator.c
@@ -5359,12 +5359,12 @@ static PyObject* CSimulator_trace(CSimulatorObject* self, PyObject* args, PyObje
     PyObject* start_obj;
     PyObject* stop_obj;
     unsigned long long max_operations;
-    unsigned long long max_tstates;
+    unsigned long long max_time;
     int interrupts;
     PyObject* disassemble;
     PyObject* trace;
 
-    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OOKKiOO", kwlist, &start_obj, &stop_obj, &max_operations, &max_tstates, &interrupts, &disassemble, &trace)) {
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OOKKiOO", kwlist, &start_obj, &stop_obj, &max_operations, &max_time, &interrupts, &disassemble, &trace)) {
         return NULL;
     }
 
@@ -5446,7 +5446,7 @@ static PyObject* CSimulator_trace(CSimulatorObject* self, PyObject* args, PyObje
         if (max_operations > 0 && operations >= max_operations) {
             return Py_BuildValue("(IL)", 1, operations);
         }
-        if (max_tstates > 0 && REG(T) >= max_tstates) {
+        if (max_time > 0 && REG(T) >= max_time) {
             return Py_BuildValue("(IL)", 2, operations);
         }
         if (REG(PC) == stop) {

diff --git a/skoolkit/trace.py b/skoolkit/trace.py
@@ -44,6 +44,11 @@ def run(self, start, stop, max_operations, max_tstates, interrupts, trace_line,
         simulator = self.simulator
         memory = simulator.memory
         registers = simulator.registers
+        start_time = registers[T]
+        if max_tstates > 0:
+            max_time = start_time + max_tstates
+        else:
+            max_time = 0
         r = Registers(registers)
 
         if hasattr(simulator, 'trace'): # pragma: no cover
@@ -52,9 +57,7 @@ def run(self, start, stop, max_operations, max_tstates, interrupts, trace_line,
                 tf = lambda pc, i, t0: print(trace_line.format(pc=pc, i=i, r=r, t=t0))
             else:
                 df = tf = None
-            stop_cond, operations = simulator.trace(start, stop, max_operations, max_tstates, interrupts, df, tf)
-            pc = registers[24]
-            tstates = registers[25]
+            stop_cond, operations = simulator.trace(start, stop, max_operations, max_time, interrupts, df, tf)
         else:
             opcodes = simulator.opcodes
             frame_duration = simulator.frame_duration
@@ -82,19 +85,19 @@ def run(self, start, stop, max_operations, max_tstates, interrupts, trace_line,
                 if operations >= max_operations > 0:
                     stop_cond = 1
                     break
-                if tstates >= max_tstates > 0:
+                if tstates >= max_time > 0:
                     stop_cond = 2
                     break
                 if pc == stop:
                     stop_cond = 3
                     break
 
         if stop_cond == 1:
-            print(f'Stopped at {prefix}{pc:{word_fmt}}: {operations} operations')
+            print(f'Stopped at {prefix}{registers[PC]:{word_fmt}}: {operations} operations')
         elif stop_cond == 2:
-            print(f'Stopped at {prefix}{pc:{word_fmt}}: {tstates} T-states')
+            print(f'Stopped at {prefix}{registers[PC]:{word_fmt}}: {registers[T] - start_time} T-states')
         elif stop_cond == 3:
-            print(f'Stopped at {prefix}{pc:{word_fmt}}')
+            print(f'Stopped at {prefix}{registers[PC]:{word_fmt}}')
         self.operations = operations
 
     def read_port(self, registers, port):

diff --git a/sphinx/source/changelog.rst b/sphinx/source/changelog.rst
@@ -20,6 +20,8 @@ Changelog
   pure Python Z80 simulator even if the C version is available)
 * Fixed the lazy evaluation bug that can make the :ref:`FONT`, :ref:`SCR` and
   :ref:`UDG` macros create frames with incorrect graphic content
+* Fixed the bug that can make :ref:`trace.py` stop too soon when the
+  ``--max-tstates`` option is used
 * Fixed the contention pattern for the OUTI/OUTD/OTIR/OTDR instructions
 
 9.1 (2024-02-03)

diff --git a/tests/test_trace.py b/tests/test_trace.py
@@ -1335,19 +1335,24 @@ def test_option_max_operations_disables_fast_ldir(self):
         self.assertLessEqual({'BC=1', 'DE=49154', 'HL=49153', 'R=6'}, set(s_reg))
 
     def test_option_max_tstates(self):
-        data = [
+        data = (
             0xAF, # XOR A
             0x3C, # INC A
-        ]
-        binfile = self.write_bin_file(data, suffix='.bin')
-        start = 32768
+        )
+        start = 0x8000
+        stop = start + len(data)
+        ram = [0] * 0xC000
+        ram[start - 0x4000:stop - 0x4000] = data
+        start_time = 4
+        registers = {'PC': start, 'tstates': start_time}
+        z80file = self.write_z80_file(None, ram, registers=registers)
         exp_output = """
             $8000 XOR A
             $8001 INC A
             Stopped at $8002: 8 T-states
         """
         for option in ('-M', '--max-tstates'):
-            output, error = self.run_trace(f'-n -o {start} -v {option} 8 {binfile}')
+            output, error = self.run_trace(f'-v {option} 8 {z80file}')
             self.assertEqual(error, '')
             self.assertEqual(dedent(exp_output).strip(), output.rstrip())