sound chips added to pld file and added sn76489 test

scripts/encode.py

@@ -106,11 +106,10 @@ class PulseWriter:
         self.bytes(struct.pack("<H", crc16(block_data)))
         self.byte(0x00) # Make sure the last byte has its last edge
 
-def header(pulses: PulseWriter, path:Path) -> None:
+def header(pulses: PulseWriter, path:Path, file_size: int) -> None:
     fname = path.name
-    fsize = os.path.getsize(path)
     data = (
-        struct.pack("<HH", math.ceil(fsize/BLOCK_SIZE), fsize)
+        struct.pack("<HH", math.ceil(file_size/BLOCK_SIZE), file_size)
         + fname.encode()[:32].ljust(32, b' ')
     )
     pulses.block(TYPE_BINARY, data)
@@ -126,6 +125,12 @@ def main() -> None:
     )
     parser.add_argument("input", type=Path, help="input file to encode")
     parser.add_argument("output", type=Path, help="output WAV file")
+    parser.add_argument(
+        "--max-size",
+        type=int,
+        metavar="BYTES",
+        help="encode at most this many bytes from the input file",
+    )
     parser.add_argument("--sample-rate", type=int, default=48_000)
     parser.add_argument(
         "--t-short",
@@ -152,6 +157,13 @@ def main() -> None:
         parser.error("--t-short must be less than --t-long")
     if not 0.0 <= args.amplitude <= 1.0:
         parser.error("--amplitude must be between 0 and 1")
+    if args.max_size is not None and args.max_size < 0:
+        parser.error("--max-size must not be negative")
+
+    input_size = os.path.getsize(args.input)
+    encoded_size = (
+        input_size if args.max_size is None else min(input_size, args.max_size)
+    )
 
     try:
         pulses = PulseWriter(
@@ -165,14 +177,14 @@ def main() -> None:
 
     # create header block
     pulses.space(5.0)
-    header(pulses, args.input)
+    header(pulses, args.input, encoded_size)
     pulses.space(1.0)
     with open(args.input, "rb") as f:
-        while True:
-            data = f.read(BLOCK_SIZE)
-            if not len(data):
-                break
+        remaining = encoded_size
+        while remaining:
+            data = f.read(min(BLOCK_SIZE, remaining))
             raw(pulses, data)
+            remaining -= len(data)
 
     pulses.space(1.0)
     with wave.open(str(args.output), "wb") as wav: