src/Flash.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 "Flash.h"
  20 #include "Instruction.h"
  21 #include "Registers.h"
  22 #include "Bus.h"
  23 #include "AccessViolation.h"
  24 #include "RuntimeException.h"
  25
  26 #include <algorithm>
  27 #include <string.h>
  28
  29 enum {
  30     NONE = 0,
  31     PGERASE = 1 << 1 | 1,
  32     RWWSRE  = 1 << 4 | 1,
  33     BLBSET  = 1 << 3 | 1,
  34     FILL    = 1,
  35     PGWRITE = 1 << 2 | 1,
  36     BUSY = 1<<6
  37 };
  38
  39 #define SPMCSR_LOWERBITS 0x1f
  40 #define BUFFERSIZE 1<<pagebits
  41 #define DEFAULT_VALUE 0xff
  42 #define setBusy() spmcsr->set( *spmcsr | BUSY );
  43
  44 // TODO these are cycles for 8Mhz!
  45 #define ERASE_CYCLES 36000
  46 #define WRITE_CYCLES 36000
  47 #define RESET_CYCLES 4
  48
  49 namespace avr {
  50
  51         static unsigned int log2Int(unsigned int v) {
  52         // find the log base 2 of 32-bit v
  53
  54         static const int MultiplyDeBruijnBitPosition[32] = {
  55             0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
  56             31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
  57         };
  58
  59         v |= v >> 1; // first round down to power of 2
  60         v |= v >> 2;
  61         v |= v >> 4;
  62         v |= v >> 8;
  63         v |= v >> 16;
  64         v = (v >> 1) + 1;
  65
  66         return MultiplyDeBruijnBitPosition[(v * 0x077CB531UL) >> 27];
  67     }
  68
  69         Flash::Flash(Bus & bus, unsigned int size, int pagesize)
  70                 : Hardware(bus), Memory(size) {
  71
  72                 pagebits = log2Int(pagesize);
  73
  74                 Memory::fill(DEFAULT_VALUE);
  75                 pagemask = (0xffffffff >> (31 - (pagebits)));
  76
  77                 buffer = new unsigned char[BUFFERSIZE];
  78                 memset(buffer, DEFAULT_VALUE, BUFFERSIZE);
  79
  80                 spmcsr = 0;
  81         }
  82
  83         Flash::~Flash() {
  84                 if( buffer != 0 )
  85                         delete [] buffer;
  86         }
  87
  88         void Flash::fill(unsigned int offset, byte val, unsigned int size) {
  89                 if( offset + size > siz )
  90                         throw AccessViolation("Flash::fill: writing too much to memory");
  91
  92                 memset( mem + offset, val, size );
  93         }
  94
  95         bool Flash::attachReg(const char *name, IORegister *reg) {
  96                 if( strcmp(name, "spmcsr") == 0 )
  97                         spmcsr = reg;
  98                 else
  99                         return false;
 100
 101                 reg->registerHW(this);
 102                 return true;
 103         }
 104
 105         bool Flash::finishBuild() {
 106                 return ( spmcsr != 0 );
 107         }
 108
 109         void Flash::regChanged( IORegister *reg ) {
 110                 if( reg == spmcsr ) {
 111                         bus.setBreakDelta(RESET_CYCLES, this);
 112                 }
 113         }
 114
 115         void Flash::storeProgramMemory(dword Z, byte r0, byte r1) {
 116         pageoffset = (Z & pagemask);
 117         pagenum = Z >> pagebits;
 118
 119         state = *spmcsr;
 120         switch ( state ) {
 121             case PGERASE:
 122                 setBusy();
 123                 bus.reassignBreakDelta(ERASE_CYCLES, this);
 124                 break;
 125
 126             case RWWSRE:
 127                 resetRWW();
 128                 bus.clearBreak(this);
 129                 break;
 130
 131             case BLBSET:
 132                 bus.clearBreak(this);
 133                 break;
 134
 135             case FILL:
 136                 if( pageoffset >= BUFFERSIZE )
 137                         throw AccessViolation("Tried to write beyond RWW buffer boundaries");
 138
 139                 buffer[pageoffset] = r0;
 140                 buffer[pageoffset+1] = r1;
 141                 spmcsr->set( *spmcsr & ~SPMCSR_LOWERBITS );
 142                 bus.clearBreak(this);
 143                 break;
 144
 145             case PGWRITE:
 146                 setBusy();
 147                 bus.reassignBreakDelta(WRITE_CYCLES, this);
 148                 break;
 149         }
 150         }
 151
 152         void Flash::resetRWW() {
 153                 if( (*spmcsr & BUSY) == 0 )
 154                         spmcsr->set( *spmcsr & ~(BUSY|SPMCSR_LOWERBITS) );
 155         }
 156
 157         void Flash::pageErase() {
 158         int size = BUFFERSIZE;
 159         int addr = pagenum * size;
 160         fill( addr, DEFAULT_VALUE, size );
 161         }
 162
 163         void Flash::pageWrite() {
 164         int size = BUFFERSIZE;
 165         int addr = pagenum * size;
 166         write( addr, buffer, size );
 167         }
 168
 169         void Flash::step() {
 170         switch ( state ) {
 171                 case NONE:
 172                         break;
 173
 174             case PGERASE:
 175                 pageErase();
 176                 break;
 177
 178             case PGWRITE:
 179                 pageWrite();
 180                 break;
 181
 182                         default:
 183                                 throw util::RuntimeException("Flash::step: invalid state");
 184         }
 185
 186                 memset(buffer, DEFAULT_VALUE, BUFFERSIZE);
 187         spmcsr->set( *spmcsr & ~(SPMCSR_LOWERBITS) );
 188         }
 189
 190 }
 191