libsidplayfp  2.11.0
SystemROMBanks.h
1 /*
2  * This file is part of libsidplayfp, a SID player engine.
3  *
4  * Copyright 2012-2022 Leandro Nini <drfiemost@users.sourceforge.net>
5  * Copyright 2010 Antti Lankila
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20  */
21 
22 #ifndef SYSTEMROMBANKS_H
23 #define SYSTEMROMBANKS_H
24 
25 #include <stdint.h>
26 #include <cstring>
27 
28 #include "Bank.h"
29 #include "c64/CPU/opcodes.h"
30 
31 #include "sidcxx11.h"
32 
33 namespace libsidplayfp
34 {
35 
39 template <int N>
40 class romBank : public Bank
41 {
42  static_assert((N != 0) && ((N & (N - 1)) == 0), "N must be a power of two");
43 
44 protected:
46  uint8_t rom[N];
47 
48 protected:
52  void setVal(uint_least16_t address, uint8_t val) { rom[address & (N-1)]=val; }
53 
57  uint8_t getVal(uint_least16_t address) const { return rom[address & (N-1)]; }
58 
62  void* getPtr(uint_least16_t address) const { return (void*)&rom[address & (N-1)]; }
63 
64 public:
68  void set(const uint8_t* source) { if (source != nullptr) std::memcpy(rom, source, N); }
69 
73  void poke(uint_least16_t, uint8_t) override {}
74 
78  uint8_t peek(uint_least16_t address) override { return rom[address & (N-1)]; }
79 };
80 
86 class KernalRomBank final : public romBank<0x2000>
87 {
88 private:
89  uint8_t resetVectorLo; // 0xfffc
90  uint8_t resetVectorHi; // 0xfffd
91 
92 public:
93  void set(const uint8_t* kernal)
94  {
95  romBank<0x2000>::set(kernal);
96 
97  if (kernal == nullptr)
98  {
99  // IRQ entry point
100  setVal(0xffa0, PHAn); // Save regs
101  setVal(0xffa1, TXAn);
102  setVal(0xffa2, PHAn);
103  setVal(0xffa3, TYAn);
104  setVal(0xffa4, PHAn);
105  setVal(0xffa5, JMPi); // Jump to IRQ routine
106  setVal(0xffa6, 0x14);
107  setVal(0xffa7, 0x03);
108 
109  // Halt
110  setVal(0xea39, 0x02);
111 
112  // Hardware vectors
113  setVal(0xfffa, 0x39); // NMI vector
114  setVal(0xfffb, 0xea);
115  setVal(0xfffc, 0x39); // RESET vector
116  setVal(0xfffd, 0xea);
117  setVal(0xfffe, 0xa0); // IRQ/BRK vector
118  setVal(0xffff, 0xff);
119  }
120 
121  // Backup Reset Vector
122  resetVectorLo = getVal(0xfffc);
123  resetVectorHi = getVal(0xfffd);
124  }
125 
126  void reset()
127  {
128  // Restore original Reset Vector
129  setVal(0xfffc, resetVectorLo);
130  setVal(0xfffd, resetVectorHi);
131  }
132 
138  void installResetHook(uint_least16_t addr)
139  {
140  setVal(0xfffc, endian_16lo8(addr));
141  setVal(0xfffd, endian_16hi8(addr));
142  }
143 };
144 
150 class BasicRomBank final : public romBank<0x2000>
151 {
152 private:
153  uint8_t trap[3];
154  uint8_t subTune[11];
155 
156 public:
157  void set(const uint8_t* basic)
158  {
159  romBank<0x2000>::set(basic);
160 
161  // Backup BASIC Warm Start
162  std::memcpy(trap, getPtr(0xa7ae), sizeof(trap));
163 
164  std::memcpy(subTune, getPtr(0xbf53), sizeof(subTune));
165  }
166 
167  void reset()
168  {
169  // Restore original BASIC Warm Start
170  std::memcpy(getPtr(0xa7ae), trap, sizeof(trap));
171 
172  std::memcpy(getPtr(0xbf53), subTune, sizeof(subTune));
173  }
174 
180  void installTrap(uint_least16_t addr)
181  {
182  setVal(0xa7ae, JMPw);
183  setVal(0xa7af, endian_16lo8(addr));
184  setVal(0xa7b0, endian_16hi8(addr));
185  }
186 
187  void setSubtune(uint8_t tune)
188  {
189  setVal(0xbf53, LDAb);
190  setVal(0xbf54, tune);
191  setVal(0xbf55, STAa);
192  setVal(0xbf56, 0x0c);
193  setVal(0xbf57, 0x03);
194  setVal(0xbf58, JSRw);
195  setVal(0xbf59, 0x2c);
196  setVal(0xbf5a, 0xa8);
197  setVal(0xbf5b, JMPw);
198  setVal(0xbf5c, 0xb1);
199  setVal(0xbf5d, 0xa7);
200  }
201 };
202 
208 class CharacterRomBank final : public romBank<0x1000> {};
209 
210 }
211 
212 #endif
Definition: Bank.h:36
Definition: SystemROMBanks.h:151
void installTrap(uint_least16_t addr)
Definition: SystemROMBanks.h:180
Definition: SystemROMBanks.h:208
Definition: SystemROMBanks.h:87
void installResetHook(uint_least16_t addr)
Definition: SystemROMBanks.h:138
Definition: SystemROMBanks.h:41
void set(const uint8_t *source)
Definition: SystemROMBanks.h:68
uint8_t peek(uint_least16_t address) override
Definition: SystemROMBanks.h:78
uint8_t getVal(uint_least16_t address) const
Definition: SystemROMBanks.h:57
void poke(uint_least16_t, uint8_t) override
Definition: SystemROMBanks.h:73
uint8_t rom[N]
The ROM array.
Definition: SystemROMBanks.h:42
void setVal(uint_least16_t address, uint8_t val)
Definition: SystemROMBanks.h:52
void * getPtr(uint_least16_t address) const
Definition: SystemROMBanks.h:62