From 82cc71261d3d32012d33d3bebe56ca5e3b0bcdbd Mon Sep 17 00:00:00 2001
From: Julian Blake Kongslie
Date: Sun, 2 Oct 2022 15:32:49 -0700
Subject: Initial commit.

---
 isa/checker.cpp | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 isa/checker.cpp

(limited to 'isa/checker.cpp')

diff --git a/isa/checker.cpp b/isa/checker.cpp
new file mode 100644
index 0000000..cd802a8
--- /dev/null
+++ b/isa/checker.cpp
@@ -0,0 +1,44 @@
+#include <cassert>
+
+#include "isa/isa.h"
+
+void checker::execute() {
+    assert(!halt);
+    auto int_enable_delay = ctlregs[ctlreg::INT_ENABLE] >> 1;
+    if (ctlregs[ctlreg::INT_ENABLE] & 1) {
+        // check for interrupt
+    }
+    ctlregs[ctlreg::INT_ENABLE] = (int_enable_delay << 1) | int_enable_delay;
+    inst = decode(ctlregs[ctlreg::DATA_INSTRUCTION_FIELD_BUFFER],
+                  pc,
+                  mem.fetch(pc));
+    auto next_pc = inst.next_pc;
+    if (inst.need_indirect_load) {
+        auto addr = mem.fetch(inst.init_address.value());
+        if (inst.need_autoinc_store)
+            mem.store(*inst.init_address, (addr + 1) & 07777);
+        inst.final_address = addr;
+    } else {
+        assert(!inst.need_autoinc_store);
+    }
+    if (inst.need_exec_load)
+        inst.data = mem.fetch(inst.final_address.value());
+    if (inst.need_read_acc)
+        inst.acc = acc;
+    if (inst.need_read_link)
+        inst.link = link;
+    if (inst.read_ctlreg.has_value())
+        inst.ctlval = ctlregs[*inst.read_ctlreg];
+    inst.execute();
+    if (inst.need_write_acc)
+        acc = inst.acc.value();
+    if (inst.need_write_link)
+        link = inst.link.value();
+    if (inst.write_ctlreg.has_value())
+        ctlregs[*inst.write_ctlreg] = inst.ctlval.value();
+    if (inst.need_exec_store)
+        mem.store(inst.final_address.value(), inst.data.value());
+    assert(inst.next_pc == next_pc || inst.possibly_redirects);
+    pc = inst.next_pc;
+    halt = inst.halt;
+}
-- 
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