src/MMU.cpp

   1 /*
   2  *      avr-sim: An atmel AVR simulator
   3  *  Copyright (C) 2008  Tom Haber
   4  *
   5  *  This program is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "MMU.h"
  20 #include "Registers.h"
  21 #include "SRam.h"
  22 #include "AccessViolation.h"
  23
  24 namespace avr {
  25
  26         MMU::MMU(unsigned int ioSpaceSize, unsigned int ramSize, ERam *eram)
  27                 : regs(ioSpaceSize), sram(ramSize), eram(eram) {
  28
  29                 static const char * Rnames[32] = {
  30                         "r0", "r1", "r2", "r3", "r4", "r5",
  31                         "r6", "r7", "r8", "r9", "r10", "r11",
  32                         "r12", "r13", "r14", "r15", "r16", "r17",
  33                         "r18", "r19", "r20", "r21", "r22", "r23",
  34                         "r24", "r25", "r26", "r27", "r28", "r29",
  35                         "r30", "r31"
  36                 };
  37                 for(int i = 0; i < 32; ++i)
  38                         R[i].init(i, Rnames[i]);
  39         }
  40
  41         MMU::~MMU() {
  42 //              if( eram != 0 )
  43 //                      delete eram;
  44         }
  45
  46         Register & MMU::reg(int i) {
  47                 if( (unsigned int)i >= registerSpaceSize )
  48                         throw AccessViolation("Tried to access not existing register");
  49
  50                 return R[i];
  51         }
  52
  53         const Register & MMU::reg(int i) const {
  54                 if( (unsigned int)i >= registerSpaceSize )
  55                         throw AccessViolation("Tried to access not existing register");
  56
  57                 return R[i];
  58         }
  59
  60         const std::string & MMU::registerName(byte addr) const {
  61                 if( addr < registerSpaceSize )
  62                         return R[addr].getName();
  63                 else
  64                         return regs.getIoreg(addr - registerSpaceSize).getName();
  65         }
  66
  67         const unsigned char *MMU::readRam(unsigned int offset, unsigned int size) const {
  68                 if( offset < registerSpaceSize + regs.size() )
  69                         throw AccessViolation("readRam: Tried to read to register area");
  70
  71                 offset -= registerSpaceSize + regs.size();
  72                 return sram.read(offset, size);
  73         }
  74
  75         void MMU::writeRam(unsigned char *data, unsigned int offset, unsigned int size) {
  76                 if( offset < registerSpaceSize + regs.size() )
  77                         throw AccessViolation("writeRam: Tried to write to register area");
  78
  79                 offset -= registerSpaceSize + regs.size();
  80                 sram.write(offset, data, size);
  81         }
  82
  83         byte MMU::readByte(unsigned int offset) const {
  84                 if( offset < registerSpaceSize )
  85                         return R[offset];
  86
  87                 offset -= registerSpaceSize;
  88                 if( offset < regs.size() )
  89                         return regs.readByte(offset);
  90
  91                 offset -= regs.size();
  92                 if( offset < sram.size() )
  93                         return sram.readByte(offset);
  94
  95                 offset -= sram.size();
  96 //              if( (eram != 0) && (offset < eram->size()) )
  97 //                      return eram->readByte(offset);
  98
  99                 throw AccessViolation();
 100         }
 101
 102         word MMU::readWord(unsigned int offset) const {
 103                 if( offset < regs.size() + registerSpaceSize )
 104                         throw AccessViolation();
 105
 106                 offset -= regs.size() + registerSpaceSize;
 107                 if( offset < sram.size() )
 108                         return sram.readByte(offset);
 109
 110                 offset -= sram.size();
 111 //              if( (eram != 0) && (offset < eram->size()) )
 112 //                      return eram->readByte(offset);
 113
 114                 throw AccessViolation();
 115         }
 116
 117         void MMU::writeByte(unsigned int offset, byte val) {
 118                 if( offset < registerSpaceSize )
 119                         R[offset] = val;
 120
 121                 offset -= registerSpaceSize;
 122                 if( offset < regs.size() )
 123                         return regs.writeByte(offset, val);
 124
 125                 offset -= regs.size();
 126                 if( offset < sram.size() )
 127                         return sram.writeByte(offset, val);
 128
 129                 offset -= sram.size();
 130 //              if( (eram != 0) && (offset < eram->size()) )
 131 //                      return eram->writeByte(offset, val);
 132
 133                 throw AccessViolation();
 134         }
 135
 136         void MMU::writeWord(unsigned int offset, word val) {
 137                 if( offset < regs.size() + registerSpaceSize )
 138                         throw AccessViolation();
 139
 140                 offset -= regs.size() + registerSpaceSize;
 141                 if( offset < sram.size() )
 142                         return sram.writeWord(offset, val);
 143
 144                 offset -= sram.size();
 145 //              if( (eram != 0) && (offset < eram->size()) )
 146 //                      return eram->writeByte(offset, val);
 147
 148                 throw AccessViolation();
 149         }
 150
 151         void MMU::addIOReg(unsigned int address,
 152                         const std::string & name, byte initial) {
 153                 IORegister *r =
 154                         new IORegister(address, name, initial);
 155                 regs.addReg( address - registerSpaceSize, r );
 156         }
 157
 158 }