Add support for debugging with LLDB

LLDB requires the qRegisterInfo packet to work correctly. While it is
possible to specify the registers manually using a Python script, having
them directly in the emulator simplifies things a lot.

diff --git a/simavr/sim/sim_gdb.c b/simavr/sim/sim_gdb.c
index de89b1c..be0320a 100644 (file)
--- a/simavr/sim/sim_gdb.c
+++ b/simavr/sim/sim_gdb.c
@@ -320,6 +320,34 @@ gdb_handle_command(
 
                                gdb_send_reply(g, rep);
                                break;
+                       } else if (strncmp(cmd, "RegisterInfo", 12) == 0) {
+                               // Send back the information we have on this register (if any).
+                               long n = strtol(cmd + 12, NULL, 16);
+                               if (n < 32) {
+                                       // General purpose (8-bit) registers.
+                                       snprintf(rep, sizeof(rep), "name:r%ld;bitsize:8;offset:0;encoding:uint;format:hex;set:General Purpose Registers;gcc:%ld;dwarf:%ld;", n, n, n);
+                                       gdb_send_reply(g, rep);
+                                       break;
+                               } else if (n == 32) {
+                                       // SREG (flags) register.
+                                       snprintf(rep, sizeof(rep), "name:sreg;bitsize:8;offset:0;encoding:uint;format:binary;set:General Purpose Registers;gcc:32;dwarf:32;");
+                                       gdb_send_reply(g, rep);
+                                       break;
+                               } else if (n == 33) {
+                                       // SP register (SPH and SPL combined).
+                                       snprintf(rep, sizeof(rep), "name:sp;bitsize:16;offset:0;encoding:uint;format:hex;set:General Purpose Registers;gcc:33;dwarf:33;generic:sp;");
+                                       gdb_send_reply(g, rep);
+                                       break;
+                               } else if (n == 34) {
+                                       // PC register
+                                       snprintf(rep, sizeof(rep), "name:pc;bitsize:32;offset:0;encoding:uint;format:hex;set:General Purpose Registers;gcc:34;dwarf:34;generic:pc;");
+                                       gdb_send_reply(g, rep);
+                                       break;
+                               } else {
+                                       // Register not available.
+                                       // By sending back nothing, the debugger knows it has read
+                                       // all available registers.
+                               }
                        }
                        gdb_send_reply(g, "");
                        break;