source: rtems/c/src/lib/libbsp/arm/nds/tools/ndstool/source/passme.cpp @ 9a12c7e5

/*
 * Includes
 */
#include "ndstool.h"
#include "crc.h"
#include "passme_sram.h"

/*
 *
 */
#define DS_RAM                  0x02000000
#define RAM_SIZE                (4*1024*1024)
unsigned char *pc_ram;

/*
 * Find
 */
template <typename T> unsigned long Find(FILE *f, const char *fmt, unsigned long begin, unsigned long end, T data, T mask, int thumb, int armnr)
{
        for (unsigned long i=begin; i<end; i+=sizeof(T))
        {
                T w = *(T *)(pc_ram + i - DS_RAM);
                w &= mask;
                if (w == data)
                {
                        if (armnr == 7)
                                header.arm7_entry_address = i + thumb;          // ARM7 entry
                        else
                                header.arm9_entry_address = i + thumb;          // ARM9 entry
                        if (f) fprintf(f, fmt, i + thumb);
                        printf(fmt, i + thumb);
                        return i;
                }
        }
        return 0;
}

/*
 * PassMe
 */
int PassMe(char *ndsfilename, char *vhdfilename, char *sramfilename)
{
        fNDS = fopen(ndsfilename, "rb");
        if (!fNDS) { fprintf(stderr, "Cannot open file '%s'.\n", ndsfilename); exit(1); }

        FILE *fVHD = fopen(vhdfilename, "wt");
        if (vhdfilename && !fVHD) { fprintf(stderr, "Cannot open file '%s'.\n", vhdfilename); exit(1); }

        fread(&header, 512, 1, fNDS);

        if (fVHD)
        {
                fprintf(fVHD, "-- PassMe generated CPLD code\n");
                fprintf(fVHD, "-- Game code: \t"); for (unsigned int i=0; i<sizeof(header.gamecode); i++) fprintf(fVHD, "%c", header.gamecode[i]); fprintf(fVHD, "\n");
                fprintf(fVHD, "-- ROM version: \t"); fprintf(fVHD, "%d\n", header.romversion);
                fprintf(fVHD, "-- Game title: \t"); for (unsigned int i=0; i<sizeof(header.title); i++) if (header.title[i]) fprintf(fVHD, "%c", header.title[i]);
                fprintf(fVHD, "\n\n");
        }

        pc_ram = new unsigned char[RAM_SIZE];

        // load ARM7 binary
        fseek(fNDS, header.arm7_rom_offset, SEEK_SET);
        fread(pc_ram + header.arm7_ram_address - DS_RAM, 1, header.arm7_size, fNDS);

        // load ARM9 binary
        fseek(fNDS, header.arm9_rom_offset, SEEK_SET);
        fread(pc_ram + header.arm9_ram_address - DS_RAM, 1, header.arm9_size, fNDS);


        header.arm7_entry_address = 0x55555555;
        header.arm9_entry_address = 0x55555555;


        unsigned char old_header[512];
        memcpy(old_header, &header, 512);

        bool bError = false;
        
        unsigned int begin9 = 0x02000000, end9 = 0x02280000;
        //unsigned int begin9 = header.arm9_ram_address, end9 = header.arm9_ram_address + header.arm9_size;
        if (!Find<unsigned long>(fVHD, "-- BX LR @ 0x%08X\n", begin9, end9, 0xE120001E, 0xFFF000FF, 0, 9))              // BX LR
//      if (!Find<unsigned short>(fVHD, "-- BX LR @ 0x%08X\n", begin9, end9, 0x4770, 0xFFFF, 1, 9))                             // BX LR
        { printf("BX LR instruction not found!\n"); bError = true; }

        unsigned int begin7 = 0x02000000, end7 = 0x023FE000;
        //unsigned int begin7 = header.arm7_ram_address, end7 = header.arm7_ram_address + header.arm7_size;
//      if (!Find<unsigned long>(fVHD, "-- SWI 0xAF @ 0x%08X\n", begin7, end7, 0xEFAF0000, 0xFFFF0000, 0, 7))           // SWI
//      if (!Find<unsigned long>(fVHD, "-- SWI 0xFF @ 0x%08X\n", begin7, end7, 0xEFFF0000, 0xFFFF0000, 0, 7))           // SWI
//      if (!Find<unsigned long>(fVHD, "-- SWI 0xA4 @ 0x%08X\n", begin7, end7, 0xEFA40000, 0xFFFF0000, 0, 7))           // SWI
//      if (!Find<unsigned long>(fVHD, "-- SWI 0xEA @ 0x%08X\n", begin7, end7, 0xEFEA0000, 0xFFFF0000, 0, 7))           // SWI
        if (!Find<unsigned short>(fVHD, "-- SWI 0xAF @ 0x%08X\n", begin7, end7, 0xDFAF, 0xFFFF, 1, 7))                          // SWI
        if (!Find<unsigned short>(fVHD, "-- SWI 0xFF @ 0x%08X\n", begin7, end7, 0xDFFF, 0xFFFF, 1, 7))                          // SWI
        if (!Find<unsigned short>(fVHD, "-- SWI 0xA4 @ 0x%08X\n", begin7, end7, 0xDFA4, 0xFFFF, 1, 7))                          // SWI
        if (!Find<unsigned short>(fVHD, "-- SWI 0xEA @ 0x%08X\n", begin7, end7, 0xDFEA, 0xFFFF, 1, 7))                          // SWI
        { printf("SWI instruction not found!\n"); bError = true; }

        //Find<unsigned long>("%08X\n", 0x037F8000, 0x0380F000, 0xEFEA0000, 0xFFFF0000, 0);             // SWI
        //...

        //Find<unsigned short>("%08X\n", 0x037F8000, 0x0380F000, 0xDFA4, 0xFFFF, 1);                            // SWI
        //...

        if (bError)
        {
                printf("Cannot patch.\n");
                return -1;
        }
        else
        {
                /*
                 * VHD
                 */

                header.reserved2 |= 0x04;       // set autostart bit

                bool forcepatch[512];
                memset(forcepatch, 0, sizeof(forcepatch));

                // ldr pc, 0x027FFE24
                ((unsigned char *)&header)[0x4] = 0x18;
                ((unsigned char *)&header)[0x5] = 0xF0;
                ((unsigned char *)&header)[0x6] = 0x9F;
                ((unsigned char *)&header)[0x7] = 0xE5;
        
                header.header_crc = CalcCrc16((unsigned char *)&header, 0x15E);
        
                if (fVHD) fputs(
                        #include "passme_vhd1.h"
                        , fVHD
                );

                for (int i=0; i<512; i++)
                {
                        if (((unsigned char *)&header)[i] != old_header[i])
                        {
                                printf("Patch:\t0x%03X\t0x%02X\n", i, ((unsigned char *)&header)[i]);
                                if (fVHD) fprintf(fVHD, "\t\t\twhen 16#%03X# => patched_data <= X\"%02X\";\n", i, ((unsigned char *)&header)[i]);
                        }
                }

                if (fVHD) fputs(
                        #include "passme_vhd2.h"
                        , fVHD
                );
                
                if (fVHD) fclose(fVHD);
                
                /*
                 * SRAM
                 */

                printf("ARM9 patched entry address: \t0x%08X\n", (unsigned int)header.arm9_entry_address);

                FILE *fSRAM = fopen(sramfilename, "wb");
                if (sramfilename && !fSRAM) { fprintf(stderr, "Cannot open file '%s'.\n", sramfilename); exit(1); }
                if (fSRAM)
                {
                        for (int i=0; i<passme_sram_size; i++)
                        {
                                unsigned char c = passme_sram[i];
                                // patch with address of ARM9 loop so it can be redirected by the code in SRAM.
                                if ((i &~ 1) == 0x764) c = header.arm9_entry_address >> 0 & 0xFF;
                                if ((i &~ 1) == 0x796) c = header.arm9_entry_address >> 8 & 0xFF;
                                if ((i &~ 1) == 0x7C8) c = header.arm9_entry_address >> 16 & 0xFF;
                                if ((i &~ 1) == 0x7FA) c = header.arm9_entry_address >> 24 & 0xFF;
                                fputc(c, fSRAM);
                        }
                        fclose(fSRAM);
                }
        }

        fclose(fNDS);
        
        return 0;
}