From c72951a36d6cb9775dc1ecd9bc26bc13e796f10c Mon Sep 17 00:00:00 2001
From: Julian Blake Kongslie
Date: Sat, 2 Jul 2022 13:45:09 -0700
Subject: Dropping the async interface, and adding some real uarch.

---
 uarch/exec.cpp | 138 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 uarch/exec.cpp

(limited to 'uarch/exec.cpp')

diff --git a/uarch/exec.cpp b/uarch/exec.cpp
new file mode 100644
index 0000000..e40813b
--- /dev/null
+++ b/uarch/exec.cpp
@@ -0,0 +1,138 @@
+#include <algorithm>
+#include <deque>
+#include <iostream>
+#include <optional>
+#include <set>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+#include "uarch/exec.h"
+#include "util/assert.h"
+
+namespace uarch {
+
+    ExecStage::ExecStage(sim::Scheduler &scheduler, sim::Queue<Uop> &execq, sim::Queue<FillReq> &fillreqq, sim::Queue<Fill> &fillq, sim::Queue<Store> &storeq)
+        : sim::Schedulable(scheduler)
+        , execq(execq)
+        , fillreqq(fillreqq)
+        , fillq(fillq)
+        , storeq(storeq)
+    {
+        execq.add_reader(this);
+        fillreqq.add_writer(this);
+        fillq.add_reader(this);
+        storeq.add_writer(this);
+    }
+
+    void ExecStage::clock()
+    {
+        if (tasks.empty() && !step && execq.available()) {
+            auto uop = execq.read();
+            std::cout << "exec accepts uop " << uop.top_task().value()->disasm() << "\n";
+            aisa::TaskStack::operator=(std::move(uop));
+            aisa::VectorRF::operator=(std::move(uop));
+        }
+
+        bool sent_store = false;
+        while (!sent_store) {
+            while (!step) {
+                auto t = top_task();
+                if (!t)
+                    goto no_work;
+                const auto &task = **t;
+                auto s = task.step(load_reg(task.environment).value());
+                if (s.has_value()) {
+                    step = std::move(s->first);
+                    std::cout << "exec step " << step->disasm() << "\n";
+                    wires = {};
+                    outstanding_fill = false;
+                    fill_complete = false;
+                    ASSERT(store_reg(task.environment, s->second), "Could not write next environment value");
+                } else {
+                    pop_task();
+                    if (tasks.empty())
+                        std::cout << "exec completes uop\n";
+                }
+            }
+
+            if (step->predicate.has_value()) {
+                auto x = load_reg(step->predicate->first);
+                if (x.has_value()) {
+                    if (*x != step->predicate->second)
+                        goto nextstep;
+                } else {
+                    std::cout << "exec stalls on predicate register";
+                    break;
+                }
+            }
+
+            wires.source_vals.reserve(step->source_regs.size());
+            for (unsigned int i = wires.source_vals.size(); i < step->source_regs.size(); ++i) {
+                auto x = load_reg(step->source_regs[i]);
+                if (!x.has_value()) {
+                    std::cout << "exec stalls on source register";
+                    break;
+                }
+                wires.source_vals.emplace_back(*x);
+            }
+
+            if (step->mop == aisa::MOp::LOAD && !fill_complete) {
+                auto mi = step->meminfo(wires);
+                if (outstanding_fill) {
+                    for (unsigned int i = 0; i < fillq.available(); ++i) {
+                        auto &fill = fillq.peek(i);
+                        if (fill.physical_addr == mi.physical_addr) {
+                            std::cout << "exec fills\n";
+                            wires.memory_val = std::move(fill.bytes);
+                            outstanding_fill = false;
+                            fill_complete = true;
+                        }
+                    }
+                    if (!fill_complete)
+                        break;
+                } else {
+                    std::cout << "exec sends fill request\n";
+                    FillReq req;
+                    req.fillq = &fillq;
+                    req.physical_addr = mi.physical_addr;
+                    req.size = mi.size;
+                    fillreqq.write(std::move(req));
+                    outstanding_fill = true;
+                    fill_complete = false;
+                    break;
+                }
+            }
+
+            step->evaluate(wires);
+
+            for (unsigned int i = 0; i < step->destination_regs.size(); ++i)
+                ASSERT(store_reg(step->destination_regs[i], wires.destination_vals[i]), "Could not write destination register");
+
+            if (step->mop == aisa::MOp::STORE) {
+                std::cout << "exec sends store\n";
+                auto mi = step->meminfo(wires);
+                Store store;
+                store.physical_addr = mi.physical_addr;
+                store.bytes = std::move(wires.memory_val);
+                storeq.write(std::move(store));
+                //sent_store = true;
+            }
+
+nextstep:
+            step = nullptr;
+            wires = {};
+            outstanding_fill = false;
+            fill_complete = false;
+        }
+
+no_work:
+
+        while (fillq.available()) {
+            std::cout << "exec consumes fill\n";
+            fillq.read();
+        }
+    }
+
+}
-- 
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