Fix read and write register blocks in gdbstub

Previously, the padding wasn't correctly accounted for which caused the gdbstub to read and write everything after R15 (starting with the dummy FPA registers) incorrectly, which caused CPSR to not be handled correctly. Everything appears to be working as expected with this change.

1 files changed, 31 insertions, 26 deletions

diff --git a/src/core/gdbstub/gdbstub.cpp b/src/core/gdbstub/gdbstub.cpp
index 003ce4167..3a2445241 100644
--- a/src/core/gdbstub/gdbstub.cpp
+++ b/src/core/gdbstub/gdbstub.cpp
@@ -57,9 +57,8 @@ const u32 MSG_WAITALL = 8;
 
 const u32 R0_REGISTER = 0;
 const u32 R15_REGISTER = 15;
-const u32 CSPR_REGISTER = 25;
+const u32 CPSR_REGISTER = 25;
 const u32 FPSCR_REGISTER = 58;
-const u32 MAX_REGISTERS = 90;
 
 namespace GDBStub {
 
@@ -472,10 +471,10 @@ static void ReadRegister() {
 
     if (id >= R0_REGISTER && id <= R15_REGISTER) {
         IntToGdbHex(reply, Core::g_app_core->GetReg(id));
-    } else if (id == CSPR_REGISTER) {
+    } else if (id == CPSR_REGISTER) {
         IntToGdbHex(reply, Core::g_app_core->GetCPSR());
-    } else if (id > CSPR_REGISTER && id < FPSCR_REGISTER) {
-        IntToGdbHex(reply, Core::g_app_core->GetVFPReg(id - CSPR_REGISTER - 1)); // VFP registers should start at 26, so one after CSPR_REGISTER
+    } else if (id > CPSR_REGISTER && id < FPSCR_REGISTER) {
+        IntToGdbHex(reply, Core::g_app_core->GetVFPReg(id - CPSR_REGISTER - 1)); // VFP registers should start at 26, so one after CSPR_REGISTER
     } else if (id == FPSCR_REGISTER) {
         IntToGdbHex(reply, Core::g_app_core->GetVFPSystemReg(VFP_FPSCR)); // Get FPSCR
         IntToGdbHex(reply + 8, 0);
@@ -492,21 +491,25 @@ static void ReadRegisters() {
     memset(buffer, 0, sizeof(buffer));
 
     u8* bufptr = buffer;
-    for (int i = 0, reg = 0; i <= MAX_REGISTERS; i++, reg++) {
-        if (i <= R15_REGISTER) {
+    for (int i = 0, reg = 0; reg <= FPSCR_REGISTER; i++, reg++) {
+        if (reg <= R15_REGISTER) {
             IntToGdbHex(bufptr + i * CHAR_BIT, Core::g_app_core->GetReg(reg));
-        } else if (i == CSPR_REGISTER) {
+        } else if (reg == CPSR_REGISTER) {
             IntToGdbHex(bufptr + i * CHAR_BIT, Core::g_app_core->GetCPSR());
-        } else if (i < CSPR_REGISTER) {
+        } else if (reg == CPSR_REGISTER - 1) {
+            // Dummy FPA register, ignore
+            IntToGdbHex(bufptr + i * CHAR_BIT, 0);
+        } else if (reg < CPSR_REGISTER) {
+            // Dummy FPA registers, ignore
             IntToGdbHex(bufptr + i * CHAR_BIT, 0);
             IntToGdbHex(bufptr + (i + 1) * CHAR_BIT, 0);
-            i++; // These registers seem to be all 64bit instead of 32bit, so skip two instead of one
-            reg++;
-        } else if (i > CSPR_REGISTER && i < MAX_REGISTERS) {
-            IntToGdbHex(bufptr + i * CHAR_BIT, Core::g_app_core->GetVFPReg(reg - CSPR_REGISTER - 1));
+            IntToGdbHex(bufptr + (i + 2) * CHAR_BIT, 0);
+            i += 2;
+        } else if (reg > CPSR_REGISTER && reg < FPSCR_REGISTER) {
+            IntToGdbHex(bufptr + i * CHAR_BIT, Core::g_app_core->GetVFPReg(reg - CPSR_REGISTER - 1));
             IntToGdbHex(bufptr + (i + 1) * CHAR_BIT, 0);
             i++;
-        } else if (i == MAX_REGISTERS) {
+        } else if (reg == FPSCR_REGISTER) {
             IntToGdbHex(bufptr + i * CHAR_BIT, Core::g_app_core->GetVFPSystemReg(VFP_FPSCR));
         }
     }
@@ -527,10 +530,10 @@ static void WriteRegister() {
 
     if (id >= R0_REGISTER && id <= R15_REGISTER) {
         Core::g_app_core->SetReg(id, GdbHexToInt(buffer_ptr));
-    } else if (id == CSPR_REGISTER) {
+    } else if (id == CPSR_REGISTER) {
         Core::g_app_core->SetCPSR(GdbHexToInt(buffer_ptr));
-    } else if (id > CSPR_REGISTER && id < FPSCR_REGISTER) {
-        Core::g_app_core->SetVFPReg(id - CSPR_REGISTER - 1, GdbHexToInt(buffer_ptr));
+    } else if (id > CPSR_REGISTER && id < FPSCR_REGISTER) {
+        Core::g_app_core->SetVFPReg(id - CPSR_REGISTER - 1, GdbHexToInt(buffer_ptr));
     } else if (id == FPSCR_REGISTER) {
         Core::g_app_core->SetVFPSystemReg(VFP_FPSCR, GdbHexToInt(buffer_ptr));
     } else {
@@ -547,18 +550,20 @@ static void WriteRegisters() {
     if (command_buffer[0] != 'G')
         return SendReply("E01");
 
-    for (int i = 0, reg = 0; i <= MAX_REGISTERS; i++, reg++) {
-        if (i <= R15_REGISTER) {
+    for (int i = 0, reg = 0; reg <= FPSCR_REGISTER; i++, reg++) {
+        if (reg <= R15_REGISTER) {
             Core::g_app_core->SetReg(reg, GdbHexToInt(buffer_ptr + i * CHAR_BIT));
-        } else if (i == CSPR_REGISTER) {
+        } else if (reg == CPSR_REGISTER) {
             Core::g_app_core->SetCPSR(GdbHexToInt(buffer_ptr + i * CHAR_BIT));
-        } else if (i < CSPR_REGISTER) {
-            i++; // These registers seem to be all 64bit instead of 32bit, so skip two instead of one
-            reg++;
-        } else if (i > CSPR_REGISTER && i < MAX_REGISTERS) {
-            Core::g_app_core->SetVFPReg(reg - CSPR_REGISTER - 1, GdbHexToInt(buffer_ptr + i * CHAR_BIT));
+        } else if (reg == CPSR_REGISTER - 1) {
+            // Dummy FPA register, ignore
+        } else if (reg < CPSR_REGISTER) {
+            // Dummy FPA registers, ignore
+            i += 2;
+        } else if (reg > CPSR_REGISTER && reg < FPSCR_REGISTER) {
+            Core::g_app_core->SetVFPReg(reg - CPSR_REGISTER - 1, GdbHexToInt(buffer_ptr + i * CHAR_BIT));
             i++; // Skip padding
-        } else if (i == MAX_REGISTERS) {
+        } else if (reg == FPSCR_REGISTER) {
             Core::g_app_core->SetVFPSystemReg(VFP_FPSCR, GdbHexToInt(buffer_ptr + i * CHAR_BIT));
         }
     }