[#13] Have a fake emulator to review resulting assembly code.

examples/.gitignore

@@ -0,0 +1 @@
+assembly_review.s

examples/CMakeLists.txt

@@ -2,6 +2,7 @@
 set(EXAMPLES
     accessing_state
     adding_memory
+    assembly_review
     benchmark
     custom_state
     hello

examples/assembly_review.cpp

@@ -0,0 +1,57 @@
+
+// A fake emulator implementation used to review resulting
+// assembly code for various instructions.
+
+#include "z80.h"
+
+using z80::fast_u8;
+using z80::fast_u16;
+
+using z80::least_u8;
+
+using z80::reg;
+
+template<typename B>
+class emulator : public B {
+public:
+    typedef B base;
+
+    emulator() {}
+
+    fast_u8 on_read(fast_u16 addr) {
+        assert(addr < z80::address_space_size);
+        return memory[addr];
+    }
+
+    void on_write(fast_u16 addr, fast_u8 n) {
+        assert(addr < z80::address_space_size);
+        memory[addr] = static_cast<least_u8>(n);
+    }
+
+private:
+    least_u8 memory[z80::address_space_size] = {};
+};
+
+class i8080_emulator : public emulator<z80::i8080_cpu<i8080_emulator>>
+{};
+
+class z80_emulator : public emulator<z80::z80_cpu<z80_emulator>>
+{};
+
+extern reg r1;
+reg r1 = reg::a;
+
+extern reg r2;
+reg r2 = reg::a;
+
+void foo(i8080_emulator &e);
+void foo(i8080_emulator &e) {
+    // e.on_decode(0x01);
+    // e.on_nop();
+    e.on_ld_r_r(r1, r2);
+}
+
+int main() {
+    i8080_emulator e;
+    foo(e);
+}

examples/assembly_review.sh

@@ -0,0 +1,6 @@
+set -e
+clang++ -I.. -DNDEBUG -O3 -c -S \
+    -fstrict-aliasing -fverbose-asm \
+    -o assembly_review.t assembly_review.cpp
+expand assembly_review.t >assembly_review.s
+rm assembly_review.t