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sfc_cpu.c
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#include "sfc_6502.h"
#include "sfc_cpu.h"
#include "sfc_famicom.h"
#include <assert.h>
#include <string.h>
// BYTE -> HEX
extern inline void sfc_btoh(char o[], uint8_t b);
// get opcode ins-len
extern inline uint8_t sfc_get_inslen(uint8_t);
/// <summary>
/// StepFC: 读取PRG数据
/// </summary>
/// <param name="address">The address.</param>
/// <param name="famicom">The famicom.</param>
/// <returns></returns>
extern inline uint8_t sfc_read_prgdata(uint16_t address, const sfc_famicom_t* famicom) {
assert(((address & (uint16_t)0x8000) == (uint16_t)0x8000) || (address>>13) == 0);
const uint16_t prgaddr = address;
return famicom->prg_banks[prgaddr >> 13][prgaddr & (uint16_t)0x1fff];
//const uint16_t id = prgaddr >> 13;
//if (id)
// return famicom->prg_banks[id][prgaddr & (uint16_t)0x1fff];
//else
// return famicom->prg_banks[0][prgaddr & (uint16_t)0x7ff];
}
/// <summary>
/// StepFC: 指定地方反汇编
/// </summary>
/// <param name="address">The address.</param>
/// <param name="famicom">The famicom.</param>
/// <param name="buf">The buf.</param>
void sfc_fc_disassembly(uint16_t address, const sfc_famicom_t* famicom, char buf[]) {
enum {
OFFSET_M = SFC_DISASSEMBLY_BUF_LEN2 - SFC_DISASSEMBLY_BUF_LEN,
OFFSET = 8
};
static_assert(OFFSET < OFFSET_M, "LESS!");
memset(buf, ' ', OFFSET);
buf[0] = '$';
sfc_btoh(buf + 1, (uint8_t)(address >> 8));
sfc_btoh(buf + 3, (uint8_t)(address));
sfc_6502_code_t code;
code.data = 0;
code.op = sfc_read_prgdata(address, famicom);
// 获取指令长度
switch (sfc_get_inslen(code.op))
{
case 3:
code.a2 = sfc_read_prgdata(address + 2, famicom);
case 2:
code.a1 = sfc_read_prgdata(address + 1, famicom);
}
// 反汇编
sfc_6502_disassembly(code, buf + OFFSET);
}
// StepFC: 读取CPU地址数据4020
extern inline uint8_t sfc_read_cpu_address4020(uint16_t, sfc_famicom_t*);
// StepFC: 写入CPU地址数据4020
extern inline void sfc_write_cpu_address4020(uint16_t, uint8_t, sfc_famicom_t*);
/// <summary>
/// StepFC: 读取CPU地址数据
/// </summary>
/// <param name="address">The address.</param>
/// <param name="famicom">The famicom.</param>
/// <returns></returns>
uint8_t sfc_read_cpu_address(uint16_t address, sfc_famicom_t* famicom) {
/*
CPU 地址空间
+---------+-------+-------+-----------------------+
| 地址 | 大小 | 标记 | 描述 |
+---------+-------+-------+-----------------------+
| $0000 | $800 | | RAM |
| $0800 | $800 | M | RAM |
| $1000 | $800 | M | RAM |
| $1800 | $800 | M | RAM |
| $2000 | 8 | | Registers |
| $2008 | $1FF8 | R | Registers |
| $4000 | $20 | | Registers |
| $4020 | $1FDF | | Expansion ROM |
| $6000 | $2000 | | SRAM |
| $8000 | $4000 | | PRG-ROM |
| $C000 | $4000 | | PRG-ROM |
+---------+-------+-------+-----------------------+
标记图例: M = $0000的镜像
R = $2000-2008 每 8 bytes 的镜像
(e.g. $2008=$2000, $2018=$2000, etc.)
*/
switch (address >> 13)
{
case 0:
// 高三位为0: [$0000, $2000): 系统主内存, 4次镜像
return famicom->main_memory[address & (uint16_t)0x07ff];
case 1:
// 高三位为1, [$2000, $4000): PPU寄存器, 8字节步进镜像
return sfc_read_ppu_register_via_cpu(address, &famicom->ppu);
case 2:
// 高三位为2, [$4000, $6000): pAPU寄存器 扩展ROM区
if (address < 0x4020)
return sfc_read_cpu_address4020(address, famicom);
//else assert(!"NOT IMPL");
return 0;
case 3:
// 高三位为3, [$6000, $8000): 存档 SRAM区
//printf("$%04X[$%02X]\n", address, famicom->save_memory[address & (uint16_t)0x1fff]);
return famicom->save_memory[address & (uint16_t)0x1fff];
case 4: case 5: case 6: case 7:
// 高一位为1, [$8000, $10000) 程序PRG-ROM区
return famicom->prg_banks[address >> 13][address & (uint16_t)0x1fff];
}
assert(!"invalid address");
return 0;
}
/// <summary>
/// SFCs the write cpu address.
/// </summary>
/// <param name="address">The address.</param>
/// <param name="data">The data.</param>
/// <param name="famicom">The famicom.</param>
void sfc_write_cpu_address(uint16_t address, uint8_t data, sfc_famicom_t* famicom) {
/*
CPU 地址空间
+---------+-------+-------+-----------------------+
| 地址 | 大小 | 标记 | 描述 |
+---------+-------+-------+-----------------------+
| $0000 | $800 | | RAM |
| $0800 | $800 | M | RAM |
| $1000 | $800 | M | RAM |
| $1800 | $800 | M | RAM |
| $2000 | 8 | | Registers |
| $2008 | $1FF8 | R | Registers |
| $4000 | $20 | | Registers |
| $4020 | $1FDF | | Expansion ROM |
| $6000 | $2000 | | SRAM |
| $8000 | $4000 | | PRG-ROM |
| $C000 | $4000 | | PRG-ROM |
+---------+-------+-------+-----------------------+
标记图例: M = $0000的镜像
R = $2000-2008 每 8 bytes 的镜像
(e.g. $2008=$2000, $2018=$2000, etc.)
*/
switch (address >> 13)
{
case 0:
// 高三位为0: [$0000, $2000): 系统主内存, 4次镜像
famicom->main_memory[address & (uint16_t)0x07ff] = data;
return;
case 1:
// 高三位为1, [$2000, $4000): PPU寄存器, 8字节步进镜像
sfc_write_ppu_register_via_cpu(address, data, &famicom->ppu);
return;
case 2:
// 高三位为2, [$4000, $6000): pAPU寄存器 扩展ROM区
// 前0x20字节为APU, I / O寄存器
if (address < 0x4020) sfc_write_cpu_address4020(address, data, famicom);
else assert(!"NOT IMPL");
return;
case 3:
// 高三位为3, [$6000, $8000): 存档 SRAM区
//printf("$%04X = $%02X\n", address, data);
famicom->save_memory[address & (uint16_t)0x1fff] = data;
return;
case 4: case 5: case 6: case 7:
// 高一位为1, [$8000, $10000) 程序PRG-ROM区
famicom->mapper.write_high(famicom, address, data);
//assert(!"WARNING: PRG-ROM");
//famicom->prg_banks[address >> 13][address & (uint16_t)0x1fff] = data;
return;
}
assert(!"invalid address");
}