Make get_snapshot() return just the 128K RAM when 'page' is -1

skoolkit/snapshot.py

@@ -96,12 +96,17 @@ def can_read(fname):
 # Component API
 def get_snapshot(fname, page=None):
     """
-    Read a snapshot file and produce a 65536-element list of byte values.
+    Read a snapshot file and produce a list of byte values. For a 48K snapshot,
+    or a 128K snapshot with a page number (0-7) specified, the list contains
+    65536 (64K) elements: a blank 16K ROM followed by 48K RAM. For a 128K
+    snapshot with `page` equal to -1, the list contains 131072 (128K) elements:
+    RAM banks 0-7 (16K each) in order.
 
     :param fname: The snapshot filename.
-    :param page: The page number to map to addresses 49152-65535 (C000-FFFF).
-                 This is relevant only when reading a 128K snapshot file.
-    :return: A 65536-element list of byte values.
+    :param page: The page number (0-7) to map to addresses 49152-65535
+                 (C000-FFFF), or -1 to return all RAM banks. This is relevant
+                 only when reading a 128K snapshot file.
+    :return: A list of byte values.
     """
     if not can_read(fname):
         raise SnapshotError("{}: Unknown file type".format(fname))
@@ -113,11 +118,11 @@ def get_snapshot(fname, page=None):
         ram = _read_z80(data, page)
     elif ext == '.szx':
         ram = _read_szx(data, page)
-    if len(ram) not in (49152, 131072):
-        raise SnapshotError("RAM size is {0}".format(len(ram)))
-    mem = [0] * 16384
-    mem.extend(ram)
-    return mem
+    if len(ram) == 49152:
+        return [0] * 16384 + list(ram)
+    if len(ram) == 131072:
+        return list(ram)
+    raise SnapshotError(f'RAM size is {len(ram)}')
 
 def make_snapshot(fname, org, start=None, end=65536, page=None):
     snapshot_reader = get_snapshot_reader()

skoolkit/trace.py

@@ -205,7 +205,7 @@ def run(snafile, options, config):
         if snafile == '48':
             memory = [0] * 0x10000
         else:
-            memory = [0] * 0x28000
+            memory = [0] * 0x20000
         reg = None
         org = 0
     else:
@@ -241,7 +241,7 @@ def run(snafile, options, config):
     elif len(memory) == 65536:
         memory[:0x4000] = read_bin_file(ROM48)
     else:
-        banks = [memory[a:a + 0x4000] for a in range(0x4000, 0x24000, 0x4000)]
+        banks = [memory[a:a + 0x4000] for a in range(0, 0x20000, 0x4000)]
         memory = Memory(banks, out7ffd)
     for spec in options.pokes:
         poke(memory, spec)

sphinx/source/components.rst

@@ -272,9 +272,9 @@ skoolkit.disassembler.OperandFormatter:
 
 Snapshot reader
 ---------------
-This object is responsible for producing a 65536-element list of byte values
-from a snapshot file. It must supply the following API functions, in common
-with skoolkit.snapshot:
+This object is responsible for producing a list of byte values from a snapshot
+file. It must supply the following API functions, in common with
+skoolkit.snapshot:
 
 .. automodule:: skoolkit.snapshot
    :members: can_read, get_snapshot

tests/test_snapshot.py

@@ -117,8 +117,7 @@ def test_sna_128k_all_pages(self):
         config.append(0) # TR-DOS ROM not paged
         sna = header + pages[5] + pages[2] + pages[3] + config + pages[0] + pages[1] + pages[4] + pages[6] + pages[7]
         tmp_sna = self.write_bin_file(sna, suffix='.sna')
-        snapshot = get_snapshot(tmp_sna, -1)
-        ram = snapshot[16384:]
+        ram = get_snapshot(tmp_sna, -1)
         self.assertEqual(len(ram), 131072)
         self.assertTrue(set(ram[0x00000:0x04000]), {5})
         self.assertTrue(set(ram[0x04000:0x08000]), {2})
@@ -133,7 +132,8 @@ class Z80Test(SnapshotTest):
     def _test_z80(self, exp_ram, version, compress, machine_id=0, modify=False, out_7ffd=0, pages={}, page=None):
         model, tmp_z80 = self.write_z80(exp_ram, version, compress, machine_id, modify, out_7ffd, pages)
         snapshot = get_snapshot(tmp_z80, page)
-        self._check_ram(snapshot[16384:], exp_ram, model, out_7ffd, pages, page)
+        ram = snapshot[16384:] if len(snapshot) == 65536 else snapshot
+        self._check_ram(ram, exp_ram, model, out_7ffd, pages, page)
 
     def test_z80v1(self):
         exp_ram = [n & 255 for n in range(49152)]
@@ -343,7 +343,8 @@ class SZXTest(SnapshotTest):
     def _test_szx(self, exp_ram, compress, machine_id=1, ch7ffd=0, pages={}, page=None):
         tmp_szx = self.write_szx(exp_ram, compress, machine_id, ch7ffd, pages)
         snapshot = get_snapshot(tmp_szx, page)
-        self._check_ram(snapshot[16384:], exp_ram, machine_id, ch7ffd, pages, page)
+        ram = snapshot[16384:] if len(snapshot) == 65536 else snapshot
+        self._check_ram(ram, exp_ram, machine_id, ch7ffd, pages, page)
 
     def test_szx_16k(self):
         exp_ram = [(n + 13) & 255 for n in range(16384)]