Eprom emulation

h8536/emulator/peripherals/__init__.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 from .lcd import LCD, LCD_E_CLOCK_DATA, LCD_E_CLOCK_STATUS, LCD_LINE_WIDTH
 from .p9_bus import P9_ACK_BIT, P9_STROBE_BIT, P9Bus, P9StrobeEvent, P9TraceEvent
-from .x24164 import X24164Bus, X24164Device, X24164TraceEvent
+from .x24164 import X24164Bus, X24164Device, X24164TraceEvent, factory_default_words_from_rom
 
 __all__ = [
     "LCD_E_CLOCK_DATA",
@@ -17,4 +17,5 @@ __all__ = [
     "X24164Bus",
     "X24164Device",
     "X24164TraceEvent",
+    "factory_default_words_from_rom",
 ]

h8536/emulator/peripherals/p9_bus.py

@@ -237,6 +237,10 @@ class P9Bus:
         self._append_x24164_trace()
         return success
 
+    def clear_x24164_trace(self) -> None:
+        self.x24164_bus.trace_events.clear()
+        self._x24164_trace_index = 0
+
     def _record_transmitted_bit(self, bit: int) -> None:
         self.transmitted_bits.append(bit)
         self.trace_events.append(P9TraceEvent("tx_bit", self.ddr, self.dr_latch, bit=bit))

h8536/emulator/peripherals/x24164.py

@@ -4,6 +4,10 @@ from dataclasses import dataclass, field
 
 
 X24164_SIZE = 2048
+X24164_FACTORY_DEFAULT_BASE = 0xC964
+X24164_FACTORY_DEFAULT_BYTES = 0x0100
+X24164_LOGICAL_PAGE_SIZE = 0x0100
+X24164_LOGICAL_PAGE_COUNT = 0x10
 
 
 @dataclass
@@ -214,6 +218,16 @@ class X24164Bus:
         )
         return True
 
+    def seed_factory_defaults_from_rom(self, rom_bytes: bytes) -> None:
+        for offset, word in factory_default_words_from_rom(rom_bytes):
+            for page in range(X24164_LOGICAL_PAGE_COUNT):
+                self.write_linear_word((page * X24164_LOGICAL_PAGE_SIZE) + offset, word)
+
+        for page in range(X24164_LOGICAL_PAGE_COUNT):
+            base = page * X24164_LOGICAL_PAGE_SIZE
+            for offset in range(0, 8, 2):
+                self.write_linear_word(base + offset, 0x2020)
+
     def trace_lines(self, limit: int | None = None) -> list[str]:
         events = self.trace_events if limit is None else self.trace_events[-limit:]
         return [event.line() for event in events]
@@ -360,3 +374,15 @@ def default_x24164_devices() -> list[X24164Device]:
         X24164Device("x24164_a0_lower_2k", 0xA0),
         X24164Device("x24164_e0_upper_2k", 0xE0),
     ]
+
+
+def factory_default_words_from_rom(rom_bytes: bytes) -> list[tuple[int, int]]:
+    end = X24164_FACTORY_DEFAULT_BASE + X24164_FACTORY_DEFAULT_BYTES
+    if len(rom_bytes) < end:
+        raise ValueError(f"ROM is too small for X24164 factory default table at {X24164_FACTORY_DEFAULT_BASE:04X}")
+    words: list[tuple[int, int]] = []
+    for offset in range(0, X24164_FACTORY_DEFAULT_BYTES, 2):
+        address = X24164_FACTORY_DEFAULT_BASE + offset
+        word = (rom_bytes[address] << 8) | rom_bytes[address + 1]
+        words.append((offset, word))
+    return words