diff options
Diffstat (limited to 'lib/nes/sys/cpu.hh')
| -rw-r--r-- | lib/nes/sys/cpu.hh | 185 |
1 files changed, 100 insertions, 85 deletions
diff --git a/lib/nes/sys/cpu.hh b/lib/nes/sys/cpu.hh index 795039c..d9d0dd0 100644 --- a/lib/nes/sys/cpu.hh +++ b/lib/nes/sys/cpu.hh @@ -9,11 +9,47 @@ namespace nes::sys { class ppu; + class cpu; class controller; class cartridge; + namespace detail + { + enum class addressing_mode + { + accumulator, // A + immediate, // #v + zero_page, // d + absolute, // a + relative, // *+d + indirect, // (a) + zero_page_indexed_x, // d,x + zero_page_indexed_y, // d,y + absolute_indexed_x, // a,x + absolute_indexed_y, // a,y + indexed_indirect, // (d,x) + indirect_indexed, // (d),y + }; + + enum class force_page_crossing + { + no, + yes, + }; + + template<detail::addressing_mode Mode> + class operand; + template<detail::addressing_mode Mode> + auto fetch_operand(cpu&, force_page_crossing = force_page_crossing::no) -> operand<Mode>; + } // namespace detail + class cpu { + template<detail::addressing_mode Mode> + friend class detail::operand; + template<detail::addressing_mode Mode> + friend auto detail::fetch_operand(cpu&, detail::force_page_crossing) -> detail::operand<Mode>; + static constexpr auto ram_size = u32{ 0x800 }; static constexpr auto stack_offset = address{ 0x100 }; @@ -55,80 +91,6 @@ namespace nes::sys } p{}; } registers_{}; - enum class addressing_mode - { - accumulator, // A - immediate, // #v - zero_page, // d - absolute, // a - relative, // *+d - indirect, // (a) - zero_page_indexed_x, // d,x - zero_page_indexed_y, // d,y - absolute_indexed_x, // a,x - absolute_indexed_y, // a,y - indexed_indirect, // (d,x) - indirect_indexed, // (d),y - }; - - enum class force_page_crossing - { - no, - yes, - }; - - template<addressing_mode> - class operand - { - cpu& cpu_; - address address_; - cycle_count cycles_; - - public: - explicit operand(cpu& cpu, address const address, cycle_count const cycles) - : cpu_{ cpu } - , address_{ address } - , cycles_{ cycles } - { - } - - auto read() -> u8 { return cpu_.read8(address_); } - auto write(u8 const value) -> void { cpu_.write8(address_, value); } - auto get_address() -> address { return address_; } - auto get_cycles() -> cycle_count { return cycles_; } - }; - - template<> - class operand<addressing_mode::accumulator> - { - cpu& cpu_; - - public: - explicit operand(cpu& cpu) - : cpu_{ cpu } - { - } - - auto read() -> u8 { return cpu_.registers_.a; } - auto write(u8 const value) -> void { cpu_.registers_.a = value; } - auto get_cycles() -> cycle_count { return cycle_count::from_cpu(2); } - }; - - template<> - class operand<addressing_mode::immediate> - { - u8 value_{ 0 }; - - public: - explicit operand(u8 const value) - : value_{ value } - { - } - - auto read() -> u8 { return value_; } - auto get_cycles() -> cycle_count { return cycle_count::from_cpu(2); } - }; - public: explicit cpu(ppu&, cartridge&, controller& controller_1, controller& controller_2); @@ -159,7 +121,7 @@ namespace nes::sys #define DEFINE_SIMPLE_INSTRUCTION(name) \ auto run_##name() -> status; #define DEFINE_OPERAND_INSTRUCTION(name) \ - template<addressing_mode Mode> auto run_##name() -> status; + template<detail::addressing_mode Mode> auto run_##name() -> status; DEFINE_OPERAND_INSTRUCTION(brk) DEFINE_OPERAND_INSTRUCTION(ora) @@ -250,7 +212,7 @@ namespace nes::sys auto pop_stack8() -> u8; auto pop_stack16() -> u16; auto update_zn(u8 value) -> void; - template<addressing_mode Mode> + template<detail::addressing_mode Mode> auto branch(bool condition) -> void; auto execute_interrupt(address) -> void; @@ -265,9 +227,69 @@ namespace nes::sys auto eval_cmp(u8 a, u8 b) -> void; auto eval_plp() -> void; auto eval_php() -> void; + }; + + namespace detail + { + template<addressing_mode> + class operand + { + cpu& cpu_; + address address_; + cycle_count cycles_; + + public: + explicit operand(cpu& cpu, address const address, cycle_count const cycles) + : cpu_{ cpu } + , address_{ address } + , cycles_{ cycles } + { + } + + auto read() -> u8 { return cpu_.read8(address_); } + auto write(u8 const value) -> void { cpu_.write8(address_, value); } + auto get_address() -> address { return address_; } + auto get_cycles() -> cycle_count { return cycles_; } + }; + + template<> + class operand<addressing_mode::accumulator> + { + cpu& cpu_; + + public: + explicit operand(cpu& cpu) + : cpu_{ cpu } + { + } + + auto read() -> u8 { return cpu_.registers_.a; } + auto write(u8 const value) -> void { cpu_.registers_.a = value; } + auto get_cycles() -> cycle_count { return cycle_count::from_cpu(2); } + }; + + template<> + class operand<addressing_mode::immediate> + { + u8 value_{ 0 }; + + public: + explicit operand(u8 const value) + : value_{ value } + { + } - // Operands + auto read() -> u8 { return value_; } + auto get_cycles() -> cycle_count { return cycle_count::from_cpu(2); } + }; + template<addressing_mode Mode> + auto fetch_operand(cpu&, force_page_crossing) -> operand<Mode>; + template<> + auto fetch_operand<addressing_mode::accumulator>(cpu&, force_page_crossing) -> operand<addressing_mode::accumulator>; + template<> + auto fetch_operand<addressing_mode::immediate>(cpu&, force_page_crossing) -> operand<addressing_mode::immediate>; + #define DEFINE_CYCLE_COUNT(name) \ template<addressing_mode Mode> static auto name##_cycle_count() -> cycle_count; #define DEFINE_CYCLE_COUNT_INSTANCE(name, mode, value) \ @@ -292,12 +314,5 @@ namespace nes::sys #undef DEFINE_CYCLE_COUNT #undef DEFINE_CYCLE_COUNT_INSTANCE - - template<addressing_mode Mode> - auto fetch_operand(force_page_crossing = force_page_crossing::no) -> operand<Mode>; - template<> - auto fetch_operand<addressing_mode::accumulator>(force_page_crossing) -> operand<addressing_mode::accumulator>; - template<> - auto fetch_operand<addressing_mode::immediate>(force_page_crossing) -> operand<addressing_mode::immediate>; - }; + } // namespace detail } // namespace nes::sys
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