tests: add execution tests

all but data processing

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

include/cpu/cpu.hh

@@ -1,58 +1,19 @@
-#pragma once
-
 #include "bus.hh"
-#include "instruction.hh"
-#include "psr.hh"
 
-#include <cstdint>
-
-using std::size_t;
+class CpuImpl;
 
 class Cpu {
   public:
-    Cpu(Bus& bus);
+    Cpu(const Bus& bus) noexcept;
+    Cpu(const Cpu&)            = delete;
+    Cpu(Cpu&&)                 = delete;
+    Cpu& operator=(const Cpu&) = delete;
+    Cpu& operator=(Cpu&&)      = delete;
+
+    ~Cpu();
+
     void step();
 
   private:
-    static constexpr uint8_t GPR_COUNT = 16;
-
-    static constexpr uint8_t GPR_FIQ_FIRST     = 8;
-    static constexpr uint8_t GPR_SVC_FIRST     = 13;
-    static constexpr uint8_t GPR_ABT_FIRST     = 13;
-    static constexpr uint8_t GPR_IRQ_FIRST     = 13;
-    static constexpr uint8_t GPR_UND_FIRST     = 13;
-    static constexpr uint8_t GPR_SYS_USR_FIRST = 8;
-
-    std::shared_ptr<Bus> bus;
-    std::array<uint32_t, GPR_COUNT> gpr; // general purpose registers
-
-    Psr cpsr; // current program status register
-    Psr spsr; // status program status register
-
-    static constexpr uint8_t PC_INDEX = 15;
-    uint32_t& pc                      = gpr[PC_INDEX];
-
-    bool is_flushed;
-
-    void chg_mode(const Mode to);
-    void exec_arm(const arm::Instruction instruction);
-
-    struct {
-        std::array<uint32_t, GPR_COUNT - GPR_FIQ_FIRST - 1> fiq;
-        std::array<uint32_t, GPR_COUNT - GPR_SVC_FIRST - 1> svc;
-        std::array<uint32_t, GPR_COUNT - GPR_ABT_FIRST - 1> abt;
-        std::array<uint32_t, GPR_COUNT - GPR_IRQ_FIRST - 1> irq;
-        std::array<uint32_t, GPR_COUNT - GPR_UND_FIRST - 1> und;
-
-        // visible registers before the mode switch
-        std::array<uint32_t, GPR_COUNT - GPR_SYS_USR_FIRST> old;
-    } gpr_banked; // banked general purpose registers
-
-    struct {
-        Psr fiq;
-        Psr svc;
-        Psr abt;
-        Psr irq;
-        Psr und;
-    } spsr_banked; // banked saved program status registers
+    std::unique_ptr<CpuImpl> impl;
 };