From 0b0ae3586c50c110dad12cc04c029106e5f2eeb5 Mon Sep 17 00:00:00 2001
From: Oxore <oxore@protonmail.com>
Date: Sun, 25 Sep 2022 21:13:36 +0300
Subject: Break execution on bus fault, support GDB NoAck mode

---
 emulator.cpp | 77 ++++++++++++++----------------------------------------------
 1 file changed, 18 insertions(+), 59 deletions(-)

(limited to 'emulator.cpp')

diff --git a/emulator.cpp b/emulator.cpp
index 945a104..ceb4217 100644
--- a/emulator.cpp
+++ b/emulator.cpp
@@ -32,6 +32,7 @@
 static constexpr struct timespec kOneMillisecond{0, 1000000};
 char msg_buf[MESSAGE_BUFFER_SIZE];
 M68KDebuggingControl g_m68k_debug{};
+bool g_no_ack_mode{};
 
 static int set_socket_reuseaddr(const int socket_fd)
 {
@@ -113,7 +114,14 @@ static std::string CreateResponse(
     case PacketType::kNone:
         break;
     case PacketType::kQuerySupported:
-        break;
+        return "PacketSize=400000" // PacketSize number is in HEX
+            // These commented-out options are from OpenOCD
+            // TODO ";qXfer:memory-map:read+"
+            // TODO ";qXfer:features:read+"
+            // TODO ";qXfer:threads:read+"
+            ";QStartNoAckMode+" // It makes GDB shit fast!
+            ";vContSupported+" // We support "vCont?" packet
+            ;
     case PacketType::kQueryHaltReason:
         return "S05"; // TODO real reason
     case PacketType::kQueryC:
@@ -145,6 +153,9 @@ static std::string CreateResponse(
             }
         }
         break;
+    case PacketType::kQStartNoAckMode:
+        g_no_ack_mode = true;
+        return "OK";
     case PacketType::kSetThreadForCont:
         return "OK";
     case PacketType::kSetThreadForOps:
@@ -287,63 +298,11 @@ int m68k_instr_callback(const int pc)
     return 0;
 }
 
-static inline bool ranges_overlap(
-        const uint32_t a_start,
-        const uint32_t a_len,
-        const uint32_t b_start,
-        const uint32_t b_len)
-{
-    return (a_start < b_start + b_len && b_start < a_start + a_len);
-}
-
-// XXX Maybe better move it to bus.cpp?
-void m68k_read_callback(const uint32_t address, const uint32_t size)
-{
-    const auto access_it = std::find_if(
-            access_bkpts.begin(),
-            access_bkpts.end(),
-            [&](const Breakpoint& b) { return ranges_overlap(address, size, b.offset, b.length); });
-    if (access_it != access_bkpts.end()) {
-        g_m68k_debug.SetRunning(false);
-        g_m68k_debug.RaiseBreakpoint();
-        m68k_end_timeslice();
-        printf("Access watchpoint @ 0x%08x\n", address);
-    }
-    const auto it = std::find_if(
-            read_bkpts.begin(),
-            read_bkpts.end(),
-            [&](const Breakpoint& b) { return ranges_overlap(address, size, b.offset, b.length); });
-    if (it != read_bkpts.end()) {
-        g_m68k_debug.SetRunning(false);
-        g_m68k_debug.RaiseBreakpoint();
-        m68k_end_timeslice();
-        printf("Read watchpoint @ 0x%08x\n", address);
-    }
-}
-
-// XXX Maybe better move it to bus.cpp?
-void m68k_write_callback(const uint32_t address, const uint32_t size)
+void m68k_breakpoint_callback(void)
 {
-    const auto access_it = std::find_if(
-            access_bkpts.begin(),
-            access_bkpts.end(),
-            [&](const Breakpoint& b) { return ranges_overlap(address, size, b.offset, b.length); });
-    if (access_it != access_bkpts.end()) {
-        g_m68k_debug.SetRunning(false);
-        g_m68k_debug.RaiseBreakpoint();
-        m68k_end_timeslice();
-        printf("Access watchpoint @ 0x%08x\n", address);
-    }
-    const auto it = std::find_if(
-            write_bkpts.begin(),
-            write_bkpts.end(),
-            [&](const Breakpoint& b) { return ranges_overlap(address, size, b.offset, b.length); });
-    if (it != write_bkpts.end()) {
-        g_m68k_debug.SetRunning(false);
-        g_m68k_debug.RaiseBreakpoint();
-        m68k_end_timeslice();
-        printf("Write watchpoint @ 0x%08x\n", address);
-    }
+    g_m68k_debug.SetRunning(false);
+    g_m68k_debug.RaiseBreakpoint();
+    m68k_end_timeslice();
 }
 
 void ParseAndReact(
@@ -363,7 +322,7 @@ void ParseAndReact(
                     "   Packet type: \"%s\"\n",
                     GDBRemote::Packet::PacketTypeToString(packet.type));
         }
-        if (res->ack.length() > 0) {
+        if (res->ack.length() > 0 && !g_no_ack_mode) {
             printf("-> \"%s\"\n", res->ack.c_str());
             if (send(conn_fd, &res->ack[0], res->ack.length(), 0) == -1)
                 perror("Send failed (ack/nak)");
@@ -428,7 +387,7 @@ int emulator(M68KDebuggingControl& m68k_debug)
                 break;
             }
             if (m68k_debug.IsRunning()) {
-                m68k_execute(1000);
+                m68k_execute(10000);
             }
             if (m68k_debug.HasBreakpoint()) {
                 m68k_debug.ResetPendingBreakpoint();
-- 
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