cpu: added hardware breakpoints on execution

JaCzekanski · Sep 3, 2019 · 2b82089 · 2b82089
1 parent bb02ebf
commit 2b82089
Show file tree

Hide file tree

Showing 5 changed files with 24 additions and 5 deletions.
diff --git a/.gitattributes b/.gitattributes
@@ -0,0 +1 @@
+*   text=auto
diff --git a/src/cpu/cop0.h b/src/cpu/cop0.h
@@ -32,6 +32,8 @@ struct COP0 {
             uint32_t superMasterEnable2 : 1;       // bits 24..29
         };
 
+        inline bool codeBreakpointEnabled() { return masterEnableBreakpoints && superMasterEnable1 && superMasterEnable2 && breakOnCode; }
+
         uint32_t _reg;
         DCIC() : _reg(0) {}
     };

diff --git a/src/cpu/cpu.cpp b/src/cpu/cpu.cpp
@@ -54,7 +54,17 @@ void CPU::saveStateForException() {
     branchTaken = false;
 }
 
-bool CPU::handleBreakpoints() {
+void CPU::handleHardwareBreakpoints() {
+    if (cop0.dcic.codeBreakpointEnabled()) {
+        if (((PC ^ cop0.bpcm) & cop0.bpc) == 0) {
+            cop0.dcic.codeBreakpointHit = 1;
+            cop0.dcic.breakpointHit = 1;
+            instructions::exception(this, COP0::CAUSE::Exception::breakpoint);
+        }
+    }
+}
+
+bool CPU::handleSoftwareBreakpoints() {
     if (!breakpoints.empty()) {
         auto bp = breakpoints.find(PC);
         if (bp != breakpoints.end() && bp->second.enabled) {
@@ -83,10 +93,10 @@ bool CPU::executeInstructions(int count) {
         if (maskedPc == 0xa0 || maskedPc == 0xb0 || maskedPc == 0xc0) sys->handleBiosFunction();
 
         saveStateForException();
-
         checkForInterrupts();
+        handleHardwareBreakpoints();
 
-        if (handleBreakpoints()) return false;
+        if (handleSoftwareBreakpoints()) return false;
 
         _opcode = Opcode(sys->readMemory32(PC));
         const auto& op = instructions::OpcodeTable[_opcode.op];

diff --git a/src/cpu/cpu.h b/src/cpu/cpu.h
@@ -96,7 +96,8 @@ struct CPU {
     }
 
     void saveStateForException();
-    bool handleBreakpoints();
+    void handleHardwareBreakpoints();
+    bool handleSoftwareBreakpoints();
     bool executeInstructions(int count);
 
     struct Breakpoint {

diff --git a/src/cpu/instructions.cpp b/src/cpu/instructions.cpp
@@ -201,7 +201,12 @@ void exception(CPU *cpu, COP0::CAUSE::Exception cause) {
         cpu->cop0.tar = cpu->PC;
     }
 
-    cpu->setPC(cpu->cop0.status.getHandlerAddress());
+    uint32_t handlerAddress = cpu->cop0.status.getHandlerAddress();
+    if (cause == Exception::breakpoint) {
+        handlerAddress -= 0x40;
+    }
+
+    cpu->setPC(handlerAddress);
 }
 
 void dummy(CPU *cpu, Opcode i) {