1 files changed, 102 insertions, 0 deletions
diff --git a/io.cpp b/io.cpp
new file mode 100644
index 0000000..e46feab
--- /dev/null
+++ b/io.cpp
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: Unlicense
+ */
+
+#include "io.hpp"
+
+#include <cstdio>
+
+uint32_t IO::Read(const uint32_t offset, const enum bitness bitness)
+{
+    uint32_t ret{};
+    if (bitness == BITNESS_32) {
+        ret = (read(offset + 3) << 24) |
+            (read(offset + 2) << 16) |
+            (read(offset + 1) << 8) |
+            read(offset + 0);
+    } else if (bitness == BITNESS_16) {
+        ret = (read(offset + 1) << 8) | read(offset + 0);
+    } else if (bitness == BITNESS_8) {
+        ret = read(offset);
+    }
+    if (DEBUG_TRACE_IO_ACCESS) {
+        printf(
+                "IO r%d%s @0x%08x 0x%0*x\n",
+                bitness * 8,
+                (bitness <= 1 ? " " : ""),
+                base_address + offset,
+                bitness * 2,
+                ret);
+    }
+    return ret;
+}
+
+void IO::Write(const uint32_t offset, const enum bitness bitness, const uint32_t value)
+{
+    if (DEBUG_TRACE_IO_ACCESS) {
+        printf(
+                "IO w%d%s @0x%08x 0x%0*x\n",
+                bitness * 8,
+                (bitness <= 1 ? " " : ""),
+                base_address + offset,
+                bitness * 2,
+                value);
+    }
+    if (bitness == BITNESS_32) {
+        write(offset + 3, value & 0xff);
+        write(offset + 2, (value >> 8) & 0xff);
+        write(offset + 1, (value >> 16) & 0xff);
+        write(offset + 0, (value >> 24) & 0xff);
+    } else if (bitness == BITNESS_16) {
+        write(offset + 0, (value >> 8) & 0xff);
+        write(offset + 1, value & 0xff);
+    } else if (bitness == BITNESS_8) {
+        write(offset, value & 0xff);
+    }
+}
+
+uint32_t IO::read(const uint32_t offset)
+{
+    switch (offset) {
+    case kData1Offset: return _data1;
+    case kData2Offset: return _data2;
+    case kData3Offset: return _data3;
+    case kControl1Offset: return _control1;
+    case kControl2Offset: return _control2;
+    case kControl3Offset: return _control3;
+    case kTx1Offset: return _tx1;
+    case kRx1Offset: return _rx1;
+    case kStatus1Offset: return _status1;
+    case kTx2Offset: return _tx2;
+    case kRx2Offset: return _rx2;
+    case kStatus2Offset: return _status2;
+    case kRx3Offset: return _tx3;
+    case kTx3Offset: return _rx3;
+    case kStatus3Offset: return _status3;
+    case kZ80BusReq: return !_z80_busreq;
+    case kZ80Reset: return 0;
+    }
+    return 0;
+}
+
+void IO::write(const uint32_t offset, const uint8_t value)
+{
+    switch (offset) {
+    case kData1Offset: _data1 = value; break;
+    case kData2Offset: _data2 = value; break;
+    case kData3Offset: _data3 = value; break;
+    case kControl1Offset: _control1 = value; break;
+    case kControl2Offset: _control2 = value; break;
+    case kControl3Offset: _control3 = value; break;
+    case kTx1Offset: _tx1 = value; break;
+    case kRx1Offset: _rx1 = value; break;
+    case kStatus1Offset: _status1 = value; break;
+    case kTx2Offset: _tx2 = value; break;
+    case kRx2Offset: _rx2 = value; break;
+    case kStatus2Offset: _status2 = value; break;
+    case kRx3Offset: _tx3 = value; break;
+    case kTx3Offset: _rx3 = value; break;
+    case kStatus3Offset: _status3 = value; break;
+    case kZ80BusReq: _z80_busreq = value & 0x1; break;
+    case kZ80Reset: _z80_reset = value & 0x1; break;
+    }
+}