From c99a4079980822255f7c6ee5e7ba99957c741aaa Mon Sep 17 00:00:00 2001
From: Dave Murphy <davem@devkitpro.org>
Date: Mon, 1 Feb 2016 12:59:32 +0000
Subject: [PATCH] Send VFP registers

---
 src/core/gdbstub/gdbstub.cpp | 68 ++++++++++++++++++++++++++++++++----
 1 file changed, 62 insertions(+), 6 deletions(-)

diff --git a/src/core/gdbstub/gdbstub.cpp b/src/core/gdbstub/gdbstub.cpp
index d155762f3..872314482 100644
--- a/src/core/gdbstub/gdbstub.cpp
+++ b/src/core/gdbstub/gdbstub.cpp
@@ -60,6 +60,59 @@ const u32 R15_REGISTER = 15;
 const u32 CPSR_REGISTER = 25;
 const u32 FPSCR_REGISTER = 58;
 
+// for sample xmls see the gdb source /gdb/features
+// gdb also wants the l character at the start
+// this XML defines what the registers are for this specific ARM device
+static const char* target_xml =
+R"(l<?xml version="1.0"?>
+<!DOCTYPE target SYSTEM "gdb-target.dtd">
+<target version="1.0">
+  <feature name="org.gnu.gdb.arm.core">
+    <reg name="r0" bitsize="32"/>
+    <reg name="r1" bitsize="32"/>
+    <reg name="r2" bitsize="32"/>
+    <reg name="r3" bitsize="32"/>
+    <reg name="r4" bitsize="32"/>
+    <reg name="r5" bitsize="32"/>
+    <reg name="r6" bitsize="32"/>
+    <reg name="r7" bitsize="32"/>
+    <reg name="r8" bitsize="32"/>
+    <reg name="r9" bitsize="32"/>
+    <reg name="r10" bitsize="32"/>
+    <reg name="r11" bitsize="32"/>
+    <reg name="r12" bitsize="32"/>
+    <reg name="sp" bitsize="32" type="data_ptr"/>
+    <reg name="lr" bitsize="32"/>
+    <reg name="pc" bitsize="32" type="code_ptr"/>
+
+    <!-- The CPSR is register 25, rather than register 16, because
+         the FPA registers historically were placed between the PC
+         and the CPSR in the "g" packet.  -->
+
+    <reg name="cpsr" bitsize="32" regnum="25"/>
+  </feature>
+  <feature name="org.gnu.gdb.arm.vfp">
+    <reg name="d0" bitsize="64" type="float"/>
+    <reg name="d1" bitsize="64" type="float"/>
+    <reg name="d2" bitsize="64" type="float"/>
+    <reg name="d3" bitsize="64" type="float"/>
+    <reg name="d4" bitsize="64" type="float"/>
+    <reg name="d5" bitsize="64" type="float"/>
+    <reg name="d6" bitsize="64" type="float"/>
+    <reg name="d7" bitsize="64" type="float"/>
+    <reg name="d8" bitsize="64" type="float"/>
+    <reg name="d9" bitsize="64" type="float"/>
+    <reg name="d10" bitsize="64" type="float"/>
+    <reg name="d11" bitsize="64" type="float"/>
+    <reg name="d12" bitsize="64" type="float"/>
+    <reg name="d13" bitsize="64" type="float"/>
+    <reg name="d14" bitsize="64" type="float"/>
+    <reg name="d15" bitsize="64" type="float"/>
+    <reg name="fpscr" bitsize="32" type="int" group="float"/>
+  </feature>
+</target>
+)";
+
 namespace GDBStub {
 
 static int gdbserver_socket = -1;
@@ -353,8 +406,15 @@ static void SendReply(const char* reply) {
 static void HandleQuery() {
     LOG_DEBUG(Debug_GDBStub, "gdb: query '%s'\n", command_buffer + 1);
 
-    if (!strcmp(reinterpret_cast<const char*>(command_buffer + 1), "TStatus")) {
+    const char *query = reinterpret_cast<const char*>(command_buffer + 1);
+
+    if (strcmp(query, "TStatus") == 0 ) {
         SendReply("T0");
+    } else if (strncmp(query, "Supported:",strlen("Supported:")) == 0) {
+        /// PacketSize needs to be large enough for target xml
+        SendReply("PacketSize=800;qXfer:features:read+");
+    } else if (strncmp(query, "Xfer:features:read:target.xml:",strlen("Xfer:features:read:target.xml:")) == 0) {
+        SendReply(target_xml);
     } else {
         SendReply("");
     }
@@ -500,10 +560,6 @@ static void ReadRegisters() {
 
     IntToGdbHex(bufptr, Core::g_app_core->GetCPSR());
 
-// Still getting "Remote 'g' packet reply is too long" from gdb with this
-// Need to figure out how to get gdb to expect vfp registers.
-
-/*
     bufptr += CHAR_BIT;
 
     for (int reg = 0; reg <= 31; reg++) {
@@ -513,7 +569,7 @@ static void ReadRegisters() {
     bufptr += (32 * CHAR_BIT);
 
     IntToGdbHex(bufptr, Core::g_app_core->GetVFPSystemReg(VFP_FPSCR));
-*/
+
     SendReply(reinterpret_cast<char*>(buffer));
 }