MMU.cpp

   1 #include "MMU.h"
   2 #include "Registers.h"
   3 #include "SRam.h"
   4 #include "AccessViolation.h"
   5
   6 namespace avr {
   7
   8         MMU::MMU(Register R[], IORegisters & regs,
   9                         SRam & sram, ERam *eram /*= 0*/) : R(R), regs(regs), sram(sram), eram(eram) {
  10         }
  11
  12         byte MMU::readByte(unsigned int offset) const {
  13                 if( offset < registerSpaceSize )
  14                         return R[offset];
  15
  16                 offset -= registerSpaceSize;
  17                 if( offset < regs.size() )
  18                         return regs.readByte(offset);
  19
  20                 offset -= regs.size();
  21                 if( offset < sram.size() )
  22                         return sram.readByte(offset);
  23
  24                 offset -= sram.size();
  25 //              if( (eram != 0) && (offset < eram->size()) )
  26 //                      return eram->readByte(offset);
  27
  28                 throw AccessViolation();
  29         }
  30
  31         word MMU::readWord(unsigned int offset) const {
  32                 if( offset < regs.size() + registerSpaceSize )
  33                         throw AccessViolation();
  34
  35                 offset -= regs.size() + registerSpaceSize;
  36                 if( offset < sram.size() )
  37                         return sram.readByte(offset);
  38
  39                 offset -= sram.size();
  40 //              if( (eram != 0) && (offset < eram->size()) )
  41 //                      return eram->readByte(offset);
  42
  43                 throw AccessViolation();
  44         }
  45
  46         void MMU::writeByte(unsigned int offset, byte val) {
  47                 if( offset < registerSpaceSize )
  48                         R[offset] = val;
  49
  50                 offset -= registerSpaceSize;
  51                 if( offset < regs.size() )
  52                         return regs.writeByte(offset, val);
  53
  54                 offset -= regs.size();
  55                 if( offset < sram.size() )
  56                         return sram.writeByte(offset, val);
  57
  58                 offset -= sram.size();
  59 //              if( (eram != 0) && (offset < eram->size()) )
  60 //                      return eram->writeByte(offset, val);
  61
  62                 throw AccessViolation();
  63         }
  64
  65         void MMU::writeWord(unsigned int offset, word val) {
  66                 if( offset < regs.size() + registerSpaceSize )
  67                         throw AccessViolation();
  68
  69                 offset -= regs.size() + registerSpaceSize;
  70                 if( offset < sram.size() )
  71                         return sram.writeWord(offset, val);
  72
  73                 offset -= sram.size();
  74 //              if( (eram != 0) && (offset < eram->size()) )
  75 //                      return eram->writeByte(offset, val);
  76
  77                 throw AccessViolation();
  78         }
  79
  80 }