thumb: add execution of instructions

also arm: fix some instructions

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

tests/cpu/cpu-fixture.hh

@@ -0,0 +1,42 @@
+#include "cpu/cpu-impl.hh"
+
+using namespace matar;
+
+class CpuFixture {
+  public:
+    CpuFixture()
+      : bus(Memory(std::array<uint8_t, Memory::BIOS_SIZE>(),
+                   std::vector<uint8_t>(Header::HEADER_SIZE)))
+      , cpu(bus) {}
+
+  protected:
+    void exec(arm::InstructionData data, Condition condition = Condition::AL) {
+        arm::Instruction instruction(condition, data);
+        instruction.exec(cpu);
+    }
+
+    void exec(thumb::InstructionData data) {
+        thumb::Instruction instruction(data);
+        instruction.exec(cpu);
+    }
+
+    void reset(uint32_t value = 0) { setr(15, value + 8); }
+
+    uint32_t getr(uint8_t r) { return getr_(r, cpu); }
+
+    void setr(uint8_t r, uint32_t value) { setr_(r, value, cpu); }
+
+    Psr psr(bool spsr = false);
+
+    void set_psr(Psr psr, bool spsr = false);
+
+    Bus bus;
+    CpuImpl cpu;
+
+  private:
+    // hack to get a register
+    uint32_t getr_(uint8_t r, CpuImpl& cpu);
+
+    // hack to set a register
+    void setr_(uint8_t r, uint32_t value, CpuImpl& cpu);
+};