mmugen.c

Source code: Embedded software for ARM processor development: MMU table generation source code.

                                                notted=0;
                                        }
                                        else
                                        {
                                                global.rule.cb |= 1 ;
                                        }
                                        //completed rule, so implement it
                                        return 1 ;

                        case NOT                 :
                                        notted=1;
                                        break;

                        case LARGEPAGES  :
                                        global.rule.entrytype = 'L';
                                        break ;

                        case SMALLPAGES  :
                                        global.rule.entrytype = 'S';
                                        break ;

            case POSTPROCESS :
                                        GetWord(buffer); //skip ENTRY
                    GetWord(buffer); //get address
                    fseek( global.outfile, atox(buffer) ,SEEK_SET );
                                        GetWord(buffer); //skip EQUALS
                                        GetWord(buffer); //get value
                    i = atox(buffer);
                    fwrite( &i, 4, 1, global.outfile );
                    break ;

                        case UNRECOGNISED:
                                        printf("Unrecognised word '%s'\n",buffer);
                }
        }

        // must have hit end of rule file without finding the end of a rule
        return 0;

}


//--WRITETABLEENTRIES--------------------------------------------------------

int WriteTableEntries (void)
{
        switch( global.state )
        {
                case 1: return WriteLevel1();
                case 2: return WriteLevel2();
                default: printf("MMU page table level not set\n");
                                 return -1;
        }
}

//--WRITELEVEL1--------------------------------------------------------------

int WriteLevel1(void)
{
        unsigned long fields ;
        unsigned long physical ;
    unsigned long writevalue ;
        unsigned long i ;

        /* Check the table-entry number matches the virtual base address for this section */
        if( global.table_entry != (global.rule.v_base>>20) )
        {
                printf("MMU Table synchronisation error!\n  table_entry = %08lx, v_base = %08lx\n",
                                global.table_entry, global.rule.v_base);
                return -1 ;
        }

        if (global.rule.entrytype == 'S' || global.rule.entrytype == 'F')
        {
                if(global.rule.entrytype == 'S')
                {
                        fields = 0x12 | (global.rule.access<<10) | (global.rule.cb<<2) ;
                }
                else
                {
                        fields = 0; //generate fault on access
                }
                physical = global.rule.p_base ;

                /* generate all the SECTION entries for this descriptor */
                for (i = global.rule.v_base; i<global.rule.v_end; )
                {
            writevalue = physical|fields ;
                        fwrite( &writevalue, 4, 1, global.outfile );
                        global.table_entry++ ;
                        physical += 0x100000 ;

                        /* check for memory wrap-round */
                        i+=0x100000 ;
                        if (i==0x00000000) break;
                }

        }
        else
        {
                /* Single PAGE entry */
        writevalue = 0x11 + global.base_address + 0x4000 + 0x400*global.pagescount++ ;
                fwrite( &writevalue, 4, 1, global.outfile );

                global.table_entry++ ;
        }

        return 0 ;

}


//--WRITELEVEL2--------------------------------------------------------------

int WriteLevel2(void)
{
        unsigned long fields ;
        unsigned long physical ;
    unsigned long writevalue ;
        unsigned long i ;
        
        /* work out repeated data fields - note: this line would change if per-page access levels were to be supported*/
        fields = (global.rule.access << 10)|(global.rule.access << 8)|(global.rule.access << 6)|(global.rule.access << 4)|(global.rule.cb <<2);

        if (global.rule.entrytype == 'L')
        {
                fields |= 1 ;
        }
        else
        {
                fields |= 2 ;
        }

        /* create entries for this descriptor */
        i = global.rule.v_base ;
        physical = global.rule.p_base ;

        while(i<global.rule.v_end)
        {
                if( global.rule.entrytype == 'L' )
                {
                        int j ;
            writevalue = physical|fields ;

                        for( j=16; j; j-- )
                        {
                                fwrite( &writevalue, 4, 1, global.outfile );
                        }
                        physical += 0x10000;
                        i += 0x10000;
                }
                else
                {
            writevalue = physical|fields ;
                        fwrite( &writevalue, 4, 1, global.outfile );
                        physical += 0x1000;
                        i += 0x1000;
                }

        }

    return 0 ;

}


//--GETWORD------------------------------------------------------------------
// fetch next word, stepping over whitespace and comments
// return 0 if end-of-file

int      GetWord (char *buffer)
{
        int c=fgetc(global.rulefile);

        while(c=='\t' || c==' ' || c=='/' || c==0xd || c==0xa)
        {
                if( c=='/') //start of comment
                {
                        do
                        {
                                c=fgetc(global.rulefile);
                        } while( c!= '/' ) ;

                        // get next character beyond comment
                        c=fgetc(global.rulefile);
                }

                while( c=='\t' || c==' ' || c==0xd || c==0xa ) c=fgetc(global.rulefile);
        }

    // Check for end of file
        if( c==EOF ) return 0;

        // Ok, should be at the start of a word
        while ( c!='\t' && c!=' ' && c!=0xd && c!=0xa && c!=EOF)
        {
                *buffer++ = (char)c ;
                c=fgetc(global.rulefile);
        }

        //terminate word
        *buffer = '\0';
        
        return 1;
}

//--GETWORDINDEX-------------------------------------------------------------

int      GetWordIndex (char *buffer)
{
    int index=0 ;
    
        while ( parsedata[index].index != UNRECOGNISED
                && stricomp(parsedata[index].word,buffer) )
        {
                index++ ;
        }
        
        return index ;
}

//--ATOX---------------------------------------------------------------------

long atox( char *buffer)
{
        long v=0;
        
        while(*buffer)
        {
                v*=16;
                if(*buffer>='0' && *buffer<='9') v+= *buffer - '0';
                if(*buffer>='a' && *buffer<='f') v+= *buffer - 'a'+10;
                if(*buffer>='A' && *buffer<='F') v+= *buffer - 'A'+10;
                buffer++;
        }
        return v ;
}

//--STRICOMP-----------------------------------------------------------------
/*
        The program originally used stricmp, but this does
        not appear to be included in the ARM C library.
        
        This is not a true stricmp (or strcmpi), since only
        the "match" string is converted to upper case,
        allowing "original" to be in read-only memory.
*/
int      stricomp( char *original, char *match )
{
        char *ptr = match ;

        while(*ptr)
        {
                *ptr=toupper(*ptr) ;
                ptr++ ;
        }
        
        return strcmp(original,match) ;
}