How to boot a .nds

From DSWiki

[edit] New

There is now a new library that does this automatically, bootlib.

Get it here: Project Page

[edit] OLD:

This method seems to work with the GBAMP only! If you know how to do this for other cards, or how to launch a .nds file from memory, please add it here!

Put this in for your arm7:

 if (*((vu32*)0x027FFE24) == (u32)0x027FFE04) {  // Check for ARM9 reset
 
   REG_IME = IME_DISABLE;   // Disable interrupts
   REG_IF = REG_IF;   // Acknowledge interrupt
   *((vu32*)0x027FFE34) = (u32)0x08000000;   // Bootloader start address
   swiSoftReset();   // Jump to boot loader
 } 
 

Put this in for arm9, customize file names for variables or fixed filenames.

 void bootGBAMPnds(void) {		
 
   REG_EXMEMCNT &= ~(0x8080);			
 
   FILE *handle = fopen("filename.nds", "rb");
   if(handle < 0) {
     iprintf("\nLoader has failed!\n");
   }
 
   struct stat st;
   u32 cluster;
 
   stat("/filename.nds", &st);
 
   cluster = st.st_ino; 
  	
   fclose(handle);
 
   REG_EXMEMCNT |= (0x8080);
 
   REG_IME = IME_DISABLE;	// Disable interrupts
   REG_EXMEMCNT |= (0x8080);  // ARM7 has access to GBA cart
   *((vu32*)0x027FFFFC) = cluster;  // Start cluster of NDS to load
   *((vu32*)0x027FFE04) = (u32)0xE59FF018;  // ldr pc, 0x027FFE24
   *((vu32*)0x027FFE24) = (u32)0x027FFE04;  // Set ARM9 Loop address
   swiSoftReset();  // Reset
 }