vgbc/tests/test_cpu_simple.cpp

#include "doctest.h"

#include "cpu/cpu.h"
#include "memory/ram.h"


TEST_CASE("simple load and add")
{
  u8 test_ram[] = {
    0x3E, 0x10, // LD A, $0x10
    0x87,       // ADD A, A
  };
  RAM r(test_ram, 3, true);
  Cpu cpu(&r);

  CHECK(cpu.state.PC == 0x0);

  cpu.step();

  CHECK(cpu.state.PC == 0x2);
  CHECK(cpu.state.A == 0x10);

  cpu.step();

  CHECK(cpu.state.PC == 0x3);
  CHECK(cpu.state.A == 0x20);
}

TEST_CASE("direct jump")
{
  u8 test_ram[] = {
    0xC3, 0x05, 0x00, // JMP $0x0005
    0x00, 0x00, // NOP NOP
    0xC3, 0x00, 0x00, // JMP $0x0000
  };

  RAM r(test_ram, 8, true);
  Cpu cpu(&r);

  CHECK(cpu.state.PC == 0x0000);

  cpu.step();

  CHECK(cpu.state.PC == 0x0005);

  cpu.step();

  CHECK(cpu.state.PC == 0x0000);
}

TEST_CASE("LD HL, nn; LD A, [HL]; LD A, n; LD [HL], A")
{
  u8 test_ram[] = {
    0x21, 0x20, 0x00, // LD HL, $0x0020
    0x7E,             // LD A, [HL]
    0x3E,0x5A,        // LD A, $0x5A
    0x77,             // LD [HL], A
    0x00,
    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
    0xA5, // . = 0x0020
  };

  RAM r(test_ram, 0x0021, false);
  Cpu cpu(&r);

  CHECK(cpu.state.PC == 0x0);

  cpu.step();

  CHECK(cpu.state.PC == 0x3);
  CHECK(cpu.state.HL == 0x0020);
  CHECK(cpu.state.A == 0x0);

  cpu.step();

  CHECK(cpu.state.PC == 0x4);
  CHECK(cpu.state.A == 0xA5);

  cpu.step();

  CHECK(cpu.state.PC == 0x6);
  CHECK(cpu.state.A == 0x5A);

  cpu.step();

  CHECK(cpu.state.PC == 0x7);
  CHECK(test_ram[0x20] == 0x5A);

}