Refactor remote bitbang code.

1 files changed, 81 insertions, 0 deletions

diff --git a/riscv/jtag_dtm.cc b/riscv/jtag_dtm.cc
new file mode 100644
index 0000000..c099e33
--- /dev/null
+++ b/riscv/jtag_dtm.cc
@@ -0,0 +1,81 @@
+#include <stdio.h>
+
+#include "jtag_dtm.h"
+
+#if 1
+#  define D(x) x
+#else
+#  define D(x)
+#endif
+
+void jtag_dtm_t::set_pins(bool tck, bool tms, bool tdi) {
+  if (!_tck && tck) {
+    // Positive clock edge.
+
+    switch (state) {
+      case SHIFT_DR:
+        dr >>= 1;
+        dr |= (uint64_t) _tdi << (dr_length-1);
+        break;
+      case SHIFT_IR:
+        ir >>= 1;
+        ir |= _tdi << (ir_length-1);
+        break;
+      default:
+        break;
+    }
+    state = next[state][_tms];
+    switch (state) {
+      case TEST_LOGIC_RESET:
+        ir = idcode_ir;
+        break;
+      case CAPTURE_DR:
+        capture_dr();
+        break;
+      case SHIFT_DR:
+        _tdo = dr & 1;
+        break;
+      case UPDATE_DR:
+        update_dr();
+        break;
+      case CAPTURE_IR:
+        break;
+      case SHIFT_IR:
+        _tdo = ir & 1;
+        break;
+      case UPDATE_IR:
+        break;
+      default:
+        break;
+    }
+  }
+
+  _tck = tck;
+  _tms = tms;
+  _tdi = tdi;
+
+  D(fprintf(stderr, "state=%2d tck=%d tms=%d tdi=%d tdo=%d ir=0x%x dr=0x%lx\n",
+        state, _tck, _tms, _tdi, _tdo, ir, dr));
+}
+
+void jtag_dtm_t::capture_dr()
+{
+  switch (ir) {
+    case idcode_ir:
+      dr = 0xdeadbeef;
+      dr_length = 32;
+      break;
+    case dtmcontrol_ir:
+      dr = dtmcontrol;
+      dr_length = 32;
+    default:
+      D(fprintf(stderr, "Unsupported IR: 0x%x\n", ir));
+      break;
+  }
+  D(fprintf(stderr, "Capture DR; IR=0x%x, DR=0x%lx (%d bits)\n",
+        ir, dr, dr_length));
+}
+
+void jtag_dtm_t::update_dr()
+{
+}