From 2bba5645c33713703cb48038f1fa56d776586b5f Mon Sep 17 00:00:00 2001
From: Eyck-Alexander Jentzsch <alex@minres.com>
Date: Wed, 16 Feb 2022 10:12:45 +0100
Subject: [PATCH] adds functionality to reduce the output

---
 incl/iss/plugin/pctrace.h |  1 +
 src/plugin/pctrace.cpp    | 52 +++++++++++++++++++++++++++++++++------
 2 files changed, 45 insertions(+), 8 deletions(-)

diff --git a/incl/iss/plugin/pctrace.h b/incl/iss/plugin/pctrace.h
index 0cad8b0..d227666 100644
--- a/incl/iss/plugin/pctrace.h
+++ b/incl/iss/plugin/pctrace.h
@@ -90,6 +90,7 @@ private:
     std::ofstream output;
     std::string filename;
     std::vector<instr_desc> delays;
+    bool jumped, first;
 
 };
 }
diff --git a/src/plugin/pctrace.cpp b/src/plugin/pctrace.cpp
index 1a92dd4..97ca4fc 100644
--- a/src/plugin/pctrace.cpp
+++ b/src/plugin/pctrace.cpp
@@ -20,6 +20,8 @@ iss::plugin::cov::cov(std::string const &filename)
     , filename(filename)
 {
     output.open("output.trc");
+    jumped = false;
+    first = true;
 }
 
 iss::plugin::cov::~cov() {
@@ -79,19 +81,53 @@ bool iss::plugin::cov::registration(const char *const version, vm_if& vm) {
 
 
 }
+
+inline string formatPC(uint64_t pc) {
+    stringstream stream;
+    stream << "0x" << std::hex << pc;
+    return stream.str();
+}
+
 void iss::plugin::cov::callback(instr_info_t iinfo, const exec_info& einfo) {
-//    if((instr_if->get_next_pc() - instr_if->get_pc() != 4) ||( instr_if->get_next_pc() - instr_if->get_pc() != 2)){
-//        std::cout << "jump from " << std::hex << instr_if->get_pc() << " to " << instr_if->get_next_pc()<< " after " << std::dec << counter <<" linear instructions" <<std::endl;
-//        counter = 0;
-//    }else {
-//        counter++;
-//    }
     auto delay = 0;
     auto entry = delays[iinfo.instr_id];
     bool taken = einfo.branch_taken;
     if (einfo.branch_taken)
         delay = entry.taken;
     else
-       delay = entry.not_taken;
-    output<<std::hex <<"0x" << instr_if->get_pc() <<"," << delay << "\n";
+        delay = entry.not_taken;
+
+    if (first){
+        output << formatPC(instr_if->get_pc()) << "," << delay;
+        first = false;
+    }
+    if(instr_if->get_next_pc()-instr_if->get_pc() != delays[iinfo.instr_id].size/8){
+        //The goal is to keep the output in start-target pairs, so after a jump the target address needs to get written
+        //to the output. If the target happens to also be a start, we keep the pairing by adding a 0-delay entry.
+        if (jumped)
+            output <<"\n" <<formatPC(instr_if->get_pc()) << "," << 0;
+        output <<"\n" << formatPC(instr_if->get_pc()) << "," << delay;
+        jumped = true;
+    }
+    else{
+        if (jumped){
+            output <<"\n" << formatPC(instr_if->get_pc()) << "," << delay;
+            jumped = false;
+        }
+        else if(delay!=1){
+            output <<"\n" << formatPC(instr_if->get_pc()) << "," << delay;
+            output <<"\n" << formatPC(instr_if->get_pc()) << "," << 0;
+        }
+
+    }
+
+//source code for the full output
+//    auto delay = 0;
+//    auto entry = delays[iinfo.instr_id];
+//    bool taken = einfo.branch_taken;
+//    if (einfo.branch_taken)
+//        delay = entry.taken;
+//    else
+//       delay = entry.not_taken;
+//    output<<std::hex <<"0x" << instr_if->get_pc() <<"," << delay << "\n";
 }