Memory debugger to break at the instruction instead of at the next one

A2Mac.xcodeproj/project.xcworkspace/xcuserdata/trudnai.xcuserdatad/xcdebugger/Expressions.xcexplist

@@ -1274,6 +1274,20 @@
             </PersistentString>
          </PersistentStrings>
       </ContextState>
+      <ContextState
+         contextName = "m6502_Debug:6502_dbg.c">
+         <PersistentStrings>
+            <PersistentString
+               value = "m6502.PC">
+            </PersistentString>
+            <PersistentString
+               value = "m6502_saved.PC">
+            </PersistentString>
+            <PersistentString
+               value = "m6502_saved">
+            </PersistentString>
+         </PersistentStrings>
+      </ContextState>
       <ContextState
          contextName = "DisplayView.mouseExited(with:):DisplayView.swift">
          <PersistentStrings>

A2Mac/DebuggerWindowController.swift

@@ -118,9 +118,20 @@ class DebuggerWindowController: NSWindowController, NSWindowDelegate {
         PauseButtonUpdate()
 
         m6502.debugger.SP = 0xFF
+
         m6502.debugger.wMask = 0
+        m6502.debugger.mask.hlt = 1;
+        m6502.debugger.mask.brk = 1;
+        m6502.debugger.mask.inv = 1;
+        
         m6502.debugger.on = true
 
+        m6502.interrupt = NO_INT
+
+        // because of memory debugger first we need to step over one instruction
+        // otherwise it would not step over that instruction
+        m6502_Step_dbg()
+        // now we cn resume to run
         ViewController.shared?.Resume()
     }
 
@@ -130,7 +141,6 @@ class DebuggerWindowController: NSWindowController, NSWindowDelegate {
 
         ViewController.shared?.Pause(0)
 
-//        m6502.debugger.wMask = 0
         m6502.debugger.on = false
     }
 
@@ -152,9 +162,21 @@ class DebuggerWindowController: NSWindowController, NSWindowDelegate {
     @IBAction func Step_Over(_ sender: Any) {
         if MEM[Int(m6502.PC)] == 0x20 {
             m6502.debugger.SP = m6502.SP > 1 ? m6502.SP : 0
+
+            m6502.debugger.wMask = 0
             m6502.debugger.mask.out = 1
+            m6502.debugger.mask.hlt = 1;
+            m6502.debugger.mask.brk = 1;
+            m6502.debugger.mask.inv = 1;
+
             m6502.debugger.on = true
 
+            m6502.interrupt = NO_INT
+
+            // because of memory debugger first we need to step over one instruction
+            // otherwise it would not step over that instruction
+            m6502_Step_dbg()
+            // now we cn resume to run
             ViewController.shared?.Resume()
         }
         else {
@@ -165,7 +187,7 @@ class DebuggerWindowController: NSWindowController, NSWindowDelegate {
 
 
     @IBAction func Step_In(_ sender: Any) {
-        m6502_Step()
+        m6502_Step_dbg()
         
         // TODO: This should be in Debugger!
         if let debugger = DebuggerViewController.shared {
@@ -181,9 +203,21 @@ class DebuggerWindowController: NSWindowController, NSWindowDelegate {
         PauseButtonUpdate()
 
         m6502.debugger.SP = m6502.SP < 0xFE ? m6502.SP + 1 : 0xFF
+
+        m6502.debugger.wMask = 0
         m6502.debugger.mask.out = 1
+        m6502.debugger.mask.hlt = 1;
+        m6502.debugger.mask.brk = 1;
+        m6502.debugger.mask.inv = 1;
+
         m6502.debugger.on = true
 
+        m6502.interrupt = NO_INT
+
+        // because of memory debugger first we need to step over one instruction
+        // otherwise it would not step over that instruction
+        m6502_Step_dbg()
+        // now we cn resume to run
         ViewController.shared?.Resume()
     }
 

A2Mac/ViewController.swift

@@ -1349,6 +1349,8 @@ class ViewController: NSViewController  {
                         break
                     }
 
+                    // clear iterrupt
+                    m6502.interrupt = NO_INT
                 }
                 else {
                     m6502_Run()

src/cpu/6502_dbg.c

@@ -54,6 +54,7 @@
 #define IRQ_VECTOR          0xFFFE
 
 extern m6502_t m6502;
+m6502_t m6502_saved;
 
 uint16_t disass_addr = 0xFDED;
 
@@ -100,7 +101,7 @@ INLINE int m6502_Step_dbg(void) {
 
 void m6502_Debug(void) {
     m6502.clktime += m6502.clkfrm;
-
+    m6502.clkfrm = 0;
     m6502.lastIO = 0;
     m6502.interrupt = NO_INT; // TODO: This should be taken care by the interrupt handler
 
@@ -114,14 +115,16 @@ void m6502_Debug(void) {
         }
     }
 
-    clk_6502_per_frm_max = clk_6502_per_frm;
+    for (
-    pc = m6502.PC;
+        m6502_saved = m6502, clk_6502_per_frm_max = clk_6502_per_frm;
-    for ( m6502.clkfrm = m6502_Step_dbg(); m6502.clkfrm < clk_6502_per_frm_max; m6502.clkfrm += m6502_Step_dbg() ) {
+        m6502.clkfrm < clk_6502_per_frm_max;
+        m6502_saved = m6502, m6502.clkfrm += m6502_Step_dbg()
+    ){
         switch (m6502.interrupt) {
             case HALT:
                 if (m6502.debugger.mask.hlt) {
                     cpuState = cpuState_halted;
-//                    m6502.debugger.wMask = 0;
+
                     return;
                 }
                 break;
@@ -129,7 +132,7 @@ void m6502_Debug(void) {
             case BREAK:
                 if (m6502.debugger.mask.brk) {
                     cpuState = cpuState_halted;
-//                    m6502.debugger.wMask = 0;
+
                     return;
                 }
                 break;
@@ -137,8 +140,13 @@ void m6502_Debug(void) {
             case BREAKRDMEM:
                 if (m6502.debugger.mask.brk) {
                     cpuState = cpuState_halted;
-//                    m6502.debugger.wMask = 0;
+
-                    m6502.PC = pc;
+                    // memory break happens *after* executing
+                    // the instruction, therefore we need to
+                    // step back to get it right in the debugger
+                    m6502_saved.interrupt = m6502.interrupt;
+                    m6502 = m6502_saved;
+
                     return;
                 }
                 break;
@@ -146,7 +154,13 @@ void m6502_Debug(void) {
             case BREAKWRMEM:
                 if (m6502.debugger.mask.brk) {
                     cpuState = cpuState_halted;
-//                    m6502.debugger.wMask = 0;
+
+                    // memory break happens *after* executing
+                    // the instruction, therefore we need to
+                    // step back to get it right in the debugger
+                    m6502_saved.interrupt = m6502.interrupt;
+                    m6502 = m6502_saved;
+
                     return;
                 }
                 break;
@@ -154,7 +168,7 @@ void m6502_Debug(void) {
             case IRQ:
                 if (m6502.debugger.mask.irq) {
                     cpuState = cpuState_halted;
-//                    m6502.debugger.wMask = 0;
+
                     return;
                 }
                 break;
@@ -162,7 +176,7 @@ void m6502_Debug(void) {
             case NMI:
                 if (m6502.debugger.mask.nmi) {
                     cpuState = cpuState_halted;
-//                    m6502.debugger.wMask = 0;
+
                     return;
                 }
                 break;
@@ -170,7 +184,7 @@ void m6502_Debug(void) {
             case INV:
                 if (m6502.debugger.mask.inv) {
                     cpuState = cpuState_halted;
-//                    m6502.debugger.wMask = 0;
+
                     return;
                 }
                 break;
@@ -180,7 +194,7 @@ void m6502_Debug(void) {
                 if (m6502.debugger.mask.out) {
                     if ( m6502.SP >= m6502.debugger.SP ) {
                         cpuState = cpuState_halted;
-//                        m6502.debugger.wMask = 0;
+
                         return;
                     }
                 }

src/cpu/6502_dbg.h

@@ -9,6 +9,7 @@
 #ifndef _6502_dbg_h
 #define _6502_dbg_h
 
+extern m6502_t m6502_saved;
 
 extern uint16_t disass_addr;
 extern void m6502_Debug(void);

src/dev/mem/mmio.c

@@ -971,6 +971,37 @@ INLINE void ioWrite( uint16_t addr, uint8_t val ) {
     return;
 }
 
+
+INLINE uint8_t is_mem_rd_bp(uint16_t addr) {
+    if (LAST_IDX(mem_read_breakpoints)) {
+        if ( m6502_dbg_bp_exists(mem_read_breakpoints, addr) ) {
+//            printf("MEM BP $%04X (bp:%04X)\n", addr, m6502.PC);
+//            cpuState = cpuState_halted;
+            m6502.interrupt = BREAKRDMEM;
+
+            return 1;
+        }
+    }
+
+    return 0;
+}
+
+
+INLINE uint8_t is_mem_wr_bp(uint16_t addr) {
+    if (LAST_IDX(mem_write_breakpoints)) {
+        if ( m6502_dbg_bp_exists(mem_write_breakpoints, addr) ) {
+//            printf("MEM BP $%04X (bp:%04X)\n", addr, m6502.PC);
+//            cpuState = cpuState_halted;
+            m6502.interrupt = BREAKWRMEM;
+
+            return 1;
+        }
+    }
+
+    return 0;
+}
+
+
 /**
  Naive implementation of RAM read from address
  **/
@@ -996,11 +1027,15 @@ INLINE uint16_t memread16_low( uint16_t addr ) {
 //    return * (uint16_t*) ( RDHIMEM + addr );
 //}
 INLINE uint16_t memread16( uint16_t addr ) {
+
+//    if (addr >= 0xC000) {
+//        return memread16_high(addr);
+//    }
     
-    //    if (addr >= 0xC000) {
+    return memread16_low(addr);
-    //        return memread16_high(addr);
+}
-    //    }
+INLINE uint16_t _memread16_dbg( uint16_t addr ) {
-    
+    is_mem_rd_bp(addr);
     return memread16_low(addr);
 }
 
@@ -1020,14 +1055,7 @@ INLINE uint8_t _memread( uint16_t addr ) {
 }
 
 INLINE uint8_t _memread_dbg( uint16_t addr ) {
-    if (LAST_IDX(mem_read_breakpoints)) {
+    is_mem_rd_bp(addr);
-        if ( m6502_dbg_bp_exists(mem_read_breakpoints, addr) ) {
-//            printf("MEM BP $%04X (bp:%04X)\n", addr, m6502.PC);
-//            cpuState = cpuState_halted;
-            m6502.interrupt = BREAKRDMEM;
-        }
-    }
-
     return _memread(addr);
 }
 
@@ -1302,6 +1330,9 @@ INLINE uint8_t _src_zp_dis() {
 INLINE uint16_t _addr_ind() {
     return memread16( _fetch() );
 }
+INLINE uint16_t _addr_ind_dbg() {
+    return _memread16_dbg( _fetch() );
+}
 INLINE uint16_t _addr_ind_dis() {
     _disPrintf(disassembly.oper, sizeof(disassembly.oper), "($%02X,X)", memread8(m6502.PC) );
     _disPrintf(disassembly.comment, sizeof(disassembly.comment), "ind_addr:%04X", memread16( memread8(m6502.PC)) );
@@ -1312,7 +1343,7 @@ INLINE uint8_t _src_ind() {
     return _memread( _addr_ind() );
 }
 INLINE uint8_t _src_ind_dbg() {
-    return _memread_dbg( _addr_ind() );
+    return _memread_dbg( _addr_ind_dbg() );
 }
 INLINE uint8_t _src_ind_dis() {
     return _memread_dis( _addr_ind_dis() );
@@ -1326,6 +1357,9 @@ INLINE uint8_t _src_ind_dis() {
 INLINE uint16_t _addr_ind_X() {
     return memread16( _fetch() + m6502.X );
 }
+INLINE uint16_t _addr_ind_X_dbg() {
+    return _memread16_dbg( _fetch() + m6502.X );
+}
 INLINE uint16_t _addr_ind_X_dis() {
     _disPrintf(disassembly.oper, sizeof(disassembly.oper), "($%02X,X)", memread8(m6502.PC) );
     _disPrintf(disassembly.comment, sizeof(disassembly.comment), "ind_addr:%04X", memread16( memread8(m6502.PC) + m6502.X) );
@@ -1336,7 +1370,7 @@ INLINE uint8_t _src_X_ind() {
     return _memread( _addr_ind_X() );
 }
 INLINE uint8_t _src_X_ind_dbg() {
-    return _memread_dbg( _addr_ind_X() );
+    return _memread_dbg( _addr_ind_X_dbg() );
 }
 INLINE uint8_t _src_X_ind_dis() {
     return _memread_dis( _addr_ind_X_dis() );