From 85b34e1c9dc03585ec4f13f6241cd8f0ecaf9cd9 Mon Sep 17 00:00:00 2001
From: Julian Blake Kongslie
Date: Sat, 8 Oct 2022 00:39:15 -0700
Subject: Trivial support for running the checker on an image.

---
 Makefile        | 20 ++++++++++++++------
 image.hex       |  4 ++++
 isa/checker.cpp |  2 +-
 isa/checker.h   | 33 ++++++++++++++++++++++++++++++---
 main.cpp        | 28 ++++++++++++++++++++++++++++
 minigolf        |  1 +
 6 files changed, 78 insertions(+), 10 deletions(-)
 create mode 100644 image.hex
 create mode 100644 main.cpp
 create mode 120000 minigolf

diff --git a/Makefile b/Makefile
index 863826d..9ae29fd 100644
--- a/Makefile
+++ b/Makefile
@@ -9,7 +9,7 @@ DEBUG := -g
 CXX := g++
 CXXFLAGS := $(WARNINGS) $(OPTIMIZE) $(DEBUG)
 
-SED := sed
+LD := ld
 
 XXD := xxd
 
@@ -30,15 +30,27 @@ clean:
 	rm -rf $(BUILD)
 .PHONY: clean
 
+.SECONDARY:
 .SUFFIXES:
 
-override SOURCES := $(shell find -\( -name build -prune -\) -o -\( -name \*.cpp -print -\))
+override SOURCES := $(shell find -\( -name build -prune -\) -o -\( -\( -name \*.bin -o -name \*.hex -o -name \*.cpp -\) -print -\))
 
 override OBJECTS := $(addprefix $(BUILD)/, $(addsuffix .o, $(basename $(SOURCES))))
 override DEPENDS := $(addprefix $(BUILD)/, $(addsuffix .d, $(basename $(SOURCES))))
 
 -include $(DEPENDS)
 
+$(BUILD)/%.bin: %.hex
+	@mkdir -p $(dir $@)
+	$(XXD) -r -p $< $@
+
+$(BUILD)/%.o: %.bin
+	@mkdir -p $(dir $@)
+	$(LD) -r -b binary -z noexecstack -o $@ $<
+
+$(BUILD)/%.o: $(BUILD)/%.bin
+	$(LD) -r -b binary -z noexecstack -o $@ $<
+
 $(BUILD)/%.o: %.cpp
 	@mkdir -p $(dir $@)
 	$(CXX) $(CXXFLAGS) $(COMPILE_FLAGS) -c -o $@ $<
@@ -46,7 +58,3 @@ $(BUILD)/%.o: %.cpp
 $(BUILD)/minigolf: $(OBJECTS)
 	@mkdir -p $(dir $@)
 	$(CXX) $(CXXFLAGS) -o $@ -Wl,--start-group $+ -Wl,--end-group $(LINK_FLAGS)
-
-$(BUILD)/%.bin: %.hex
-	@mkdir -p $(dir $@)
-	$(SED) -e "s/\\s*#.*//" $< | $(XXD) -r -p > $@
diff --git a/image.hex b/image.hex
new file mode 100644
index 0000000..6c7573e
--- /dev/null
+++ b/image.hex
@@ -0,0 +1,4 @@
+0001 0002 0004
+0008 0010 0020
+0040 0080 0100
+0200 0400 0800
diff --git a/isa/checker.cpp b/isa/checker.cpp
index 604279a..05b59a9 100644
--- a/isa/checker.cpp
+++ b/isa/checker.cpp
@@ -10,7 +10,7 @@ void checker::execute() {
         // check for interrupt
     }
     ctlregs[INT_ENABLE] = (int_enable_delay << 1) | int_enable_delay;
-    auto inst = decode(ctlregs[DATA_INSTRUCTION_FIELD_BUFFER],
+    inst = decode(ctlregs[DATA_INSTRUCTION_FIELD_BUFFER],
                   pc,
                   mem.fetch(pc));
     auto next_pc = inst.next_pc;
diff --git a/isa/checker.h b/isa/checker.h
index 6aae3ff..70393b6 100644
--- a/isa/checker.h
+++ b/isa/checker.h
@@ -1,19 +1,46 @@
 #pragma once
 
 #include <array>
+#include <map>
 
 #include "isa/isa.h"
 
 struct funcmem {
-    unsigned int fetch(unsigned int address);
-    void store(unsigned int address, unsigned int value);
+    static constexpr unsigned int PAGE_BYTES_LOG2 = 20;
+    static constexpr unsigned int PAGE_BYTES = 1 << PAGE_BYTES_LOG2;
+    static constexpr unsigned int PAGE_BYTE_OFFSET_MASK = PAGE_BYTES - 1;
+
+    typedef std::array<unsigned int, PAGE_BYTES> page;
+
+    std::map<unsigned int, page> image;
+
+    unsigned int fetch(unsigned int address) const {
+        auto page_address = address >> PAGE_BYTES_LOG2;
+        auto page_offset = address & PAGE_BYTE_OFFSET_MASK;
+        if (auto p = image.find(page_address); p != image.end()) {
+            const auto &page = p->second;
+            return page[page_offset];
+        }
+        return 0;
+    }
+
+    void store(unsigned int address, unsigned int value) {
+        auto page_address = address >> PAGE_BYTES_LOG2;
+        auto page_offset = address & PAGE_BYTE_OFFSET_MASK;
+        auto [p, emplaced] = image.try_emplace(page_address);
+        auto &page = p->second;
+        if (emplaced)
+            page.fill(0);
+        page[page_offset] = value;
+    }
 };
 
 struct checker {
     unsigned int acc = 0;
     unsigned int link = 0;
-    unsigned int pc = 0;
+    unsigned int pc = 00200;
     std::array<unsigned int, NUM_CTLREGS> ctlregs;
+    instruction_context inst;
     bool halted = false;
     funcmem mem;
     void execute();
diff --git a/main.cpp b/main.cpp
new file mode 100644
index 0000000..bc17427
--- /dev/null
+++ b/main.cpp
@@ -0,0 +1,28 @@
+#include <arpa/inet.h>
+#include <cstdint>
+#include <fmt/format.h>
+#include <iostream>
+
+#include "isa/checker.h"
+
+extern std::uint16_t _binary_build___image_bin_start[];
+extern std::uint16_t _binary_build___image_bin_end[];
+
+int main(int argc, const char *argv[]) {
+    checker checker;
+
+    unsigned int address = 0;
+    for (auto *src = _binary_build___image_bin_start; src < _binary_build___image_bin_end; ++src, ++address) {
+        auto word = ntohs(*src);
+        std::cout << fmt::format("mem[{:04o}] = {:04o}\n", address, word);
+        checker.mem.store(address, word);
+    }
+
+    while (!checker.halted) {
+        std::cout << fmt::format("{:04o}: ", checker.pc);
+        checker.execute();
+        std::cout << fmt::format("acc={:04o}\n", checker.acc);
+    }
+
+    return 0;
+}
diff --git a/minigolf b/minigolf
new file mode 120000
index 0000000..b6cb41a
--- /dev/null
+++ b/minigolf
@@ -0,0 +1 @@
+build/minigolf
\ No newline at end of file
-- 
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