Add cycle(h) and instret(h)

Partial fix to #2

rars/riscv/hardware/ControlAndStatusRegisterFile.java

@@ -61,7 +61,11 @@ public class ControlAndStatusRegisterFile {
                 new Register("uepc", 0x041, 0),
                 new Register("ucause", 0x042, 0),
                 new Register("utval", 0x043, 0),
-                new Register("uip", 0x044, 0)
+                new Register("uip", 0x044, 0),
+                new ReadOnlyRegister("cycle", 0xC00, 0, -1),
+                new ReadOnlyRegister("instret",0xC02, 0, -1),
+                new ReadOnlyRegister("cycleh", 0xC80, 0, -1),
+                new ReadOnlyRegister("instreth",0xC81, 0, -1),
         };
         tmp[1] = new LinkedRegister("fflags", 0x001, tmp[3], 0x1F);
         tmp[2] = new LinkedRegister("frm", 0x002, tmp[3], 0xE0);
@@ -92,6 +96,30 @@ public static int updateRegister(String name, int val) {
         return updateRegister(instance.getRegister(name).getNumber(), val);
     }
 
+    /**
+     * This method updates the register value silently and bypasses read only
+     *
+     * @param num Number of register to set the value of.
+     * @param val  The desired value for the register.
+     * @return old value in register prior to update
+     **/
+    public static int updateRegisterBackdoor(int num, int val) {
+        return (Globals.getSettings().getBackSteppingEnabled())
+                ? Globals.program.getBackStepper().addControlAndStatusBackdoor(num, instance.getRegister(num).setValueBackdoor(val))
+                : instance.getRegister(num).setValueBackdoor(val);
+    }
+
+    /**
+     * This method updates the register value silently and bypasses read only
+     *
+     * @param name Name of register to set the value of.
+     * @param val  The desired value for the register.
+     * @return old value in register prior to update
+     **/
+    public static int updateRegisterBackdoor(String name, int val) {
+        return updateRegisterBackdoor(instance.getRegister(name).getNumber(), val);
+    }
+
     /**
      * ORs a register with a value
      *

rars/riscv/hardware/ReadOnlyRegister.java

@@ -0,0 +1,52 @@
+package rars.riscv.hardware;
+
+/*
+Copyright (c) 2019,  Benjamin Landers
+
+Developed by Benjamin Landers ([email protected])
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject
+to the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
+ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
+CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+(MIT license, http://www.opensource.org/licenses/mit-license.html)
+ */
+
+/**
+ * A register which aliases a subset of another register
+ */
+public class ReadOnlyRegister extends Register {
+    private int mask;
+
+    /**
+     * @param name the name to assign
+     * @param num  the number to assign
+     * @param val the reset value
+     * @param mask the bits to use
+     */
+    public ReadOnlyRegister(String name, int num, int val, int mask) {
+        super(name, num, val); // reset value does not matter
+        this.mask = mask;
+    }
+
+    public synchronized int setValue(int val) {
+        int current = getValue();
+        super.setValue((current & mask) | (val & ~mask));
+        return current;
+    }
+}

rars/riscv/hardware/Register.java

@@ -131,6 +131,21 @@ public synchronized int setValue(int val) {
         return old;
     }
 
+    /**
+     * Sets the value of the register to the val passed to it. This should only
+     * be used to update registers not related to the current instruction.
+     *
+     * @param val Value to set the Register to.
+     * @return previous value of register
+     */
+
+    public synchronized int setValueBackdoor(int val) {
+        int old = value;
+        value = val;
+        return old;
+    }
+
+
     /**
      * Resets the value of the register to the value it was constructed with.
      * Observers are not notified.

rars/simulator/BackStepper.java

@@ -51,6 +51,7 @@ private enum Action {
         REGISTER_RESTORE,
         PC_RESTORE,
         CONTROL_AND_STATUS_REGISTER_RESTORE,
+        CONTROL_AND_STATUS_REGISTER_BACKDOOR,
         FLOATING_POINT_REGISTER_RESTORE,
         DO_NOTHING
     }
@@ -155,6 +156,9 @@ public void backStep() {
                         case CONTROL_AND_STATUS_REGISTER_RESTORE:
                             ControlAndStatusRegisterFile.updateRegister(step.param1,step.param2);
                             break;
+                        case CONTROL_AND_STATUS_REGISTER_BACKDOOR:
+                            ControlAndStatusRegisterFile.updateRegisterBackdoor(step.param1,step.param2);
+                            break;
                         case PC_RESTORE:
                             RegisterFile.setProgramCounter(step.param1);
                             break;
@@ -275,6 +279,21 @@ public int addControlAndStatusRestore(int register, int value) {
         return value;
     }
 
+
+    /**
+     * Add a new "back step" (the undo action) to the stack.  The action here
+     * is to restore a control and status register value. This does not obey
+     * read only restrictions and does not notify observers.
+     *
+     * @param register The affected register number.
+     * @param value    The "restore" value to be stored there.
+     * @return the argument value
+     */
+    public int addControlAndStatusBackdoor(int register, int value) {
+        backSteps.push(Action.CONTROL_AND_STATUS_REGISTER_BACKDOOR, pc(), register, value);
+        return value;
+    }
+
     /**
      * Add a new "back step" (the undo action) to the stack.  The action here
      * is to restore a floating point register value.

rars/simulator/Simulator.java

@@ -1,10 +1,7 @@
 package rars.simulator;
 
 import rars.*;
-import rars.riscv.hardware.AddressErrorException;
-import rars.riscv.hardware.ControlAndStatusRegisterFile;
-import rars.riscv.hardware.InterruptController;
-import rars.riscv.hardware.RegisterFile;
+import rars.riscv.hardware.*;
 import rars.riscv.BasicInstruction;
 import rars.riscv.Instruction;
 import rars.util.Binary;
@@ -519,7 +516,23 @@ public void run() {
                     }
                 }// end synchronized block
 
-                //	Return if we've reached a breakpoint.
+                // Update cycle(h) and instret(h)
+                int cycle = ControlAndStatusRegisterFile.getValueNoNotify("cycle"),
+                         instret = ControlAndStatusRegisterFile.getValueNoNotify("instret");
+                ControlAndStatusRegisterFile.updateRegisterBackdoor("cycle",cycle+1);
+                if(cycle == -1){
+                    int cycleh = ControlAndStatusRegisterFile.getValueNoNotify("cycleh");
+                    ControlAndStatusRegisterFile.updateRegisterBackdoor("cycleh",cycleh+1);
+                }
+
+                ControlAndStatusRegisterFile.updateRegisterBackdoor("instret",instret+1);
+                if(instret == -1){
+                    int instreth = ControlAndStatusRegisterFile.getValueNoNotify("instreth");
+                    ControlAndStatusRegisterFile.updateRegisterBackdoor("instreth",instreth+1);
+                }
+
+
+                //     Return if we've reached a breakpoint.
                 if (ebreak || (breakPoints != null) &&
                         (Arrays.binarySearch(breakPoints, RegisterFile.getProgramCounter()) >= 0)) {
                     stopExecution(false, Reason.BREAKPOINT);