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bus: separate out read/write that count cycles

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Signed-off-by: Amneesh Singh <natto@weirdnatto.in>
This commit is contained in:
Amneesh Singh
2024-06-19 14:53:31 +05:30
parent f5aa73e7ca
commit 7d3996526f
9 changed files with 262 additions and 282 deletions
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67
include/bus.hh
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@@ -5,10 +5,20 @@
#include <memory>
#include <optional>
#include <span>
#include <unordered_map>
#include <vector>
namespace matar {
enum CpuAccess {
Sequential,
NonSequential
};
enum CpuAccessWidth {
Word,
Halfword,
Byte
};
class Bus {
private:
struct Private {
@@ -23,20 +33,57 @@ class Bus {
static std::shared_ptr<Bus> init(std::array<uint8_t, BIOS_SIZE>&&,
std::vector<uint8_t>&&);
uint8_t read_byte(uint32_t, bool = true);
void write_byte(uint32_t, uint8_t, bool = true);
uint8_t read_byte(uint32_t address, CpuAccess access) {
add_cpu_cycles<CpuAccessWidth::Byte>(address, access);
return read_byte(address);
};
void write_byte(uint32_t address, uint8_t byte, CpuAccess access) {
add_cpu_cycles<CpuAccessWidth::Byte>(address, access);
write_byte(address, byte);
};
uint16_t read_halfword(uint32_t, bool = true);
void write_halfword(uint32_t, uint16_t, bool = true);
uint16_t read_halfword(uint32_t address, CpuAccess access) {
add_cpu_cycles<CpuAccessWidth::Halfword>(address, access);
return read_halfword(address);
}
void write_halfword(uint32_t address, uint16_t halfword, CpuAccess access) {
add_cpu_cycles<CpuAccessWidth::Halfword>(address, access);
write_halfword(address, halfword);
}
uint32_t read_word(uint32_t address, CpuAccess access) {
add_cpu_cycles<CpuAccessWidth::Word>(address, access);
return read_word(address);
}
void write_word(uint32_t address, uint32_t word, CpuAccess access) {
add_cpu_cycles<CpuAccessWidth::Word>(address, access);
write_word(address, word);
}
uint8_t read_byte(uint32_t address);
void write_byte(uint32_t address, uint8_t byte);
uint16_t read_halfword(uint32_t address);
void write_halfword(uint32_t address, uint16_t halfword);
uint32_t read_word(uint32_t address);
void write_word(uint32_t address, uint32_t word);
uint32_t read_word(uint32_t, bool = true);
void write_word(uint32_t, uint32_t, bool = true);
// not sure what else to do?
inline void internal_cycle() { cycles++; }
inline uint32_t get_cycles() { return cycles; }
void internal_cycle() { cycles++; }
uint32_t get_cycles() { return cycles; }
private:
template<CpuAccessWidth W>
void add_cpu_cycles(uint32_t address, CpuAccess access) {
auto cc = cycle_map[address >> 24 & 0xF];
if constexpr (W == CpuAccessWidth::Word) {
cycles += (access == CpuAccess::Sequential ? cc.s32 : cc.n32);
} else {
cycles += (access == CpuAccess::Sequential ? cc.s16 : cc.n16);
}
}
template<unsigned int>
std::optional<std::span<const uint8_t>> read(uint32_t) const;