ARM9 SWI Functions

From DSiBrew
Jump to navigation Jump to search

ARM9 BIOS SWI Function

These are the functions provided by the ARM9 BIOS.

ID Name Args Changes
0x00 N/A (hangs) none formerly SoftReset
0x01 swiDecompressLZSSwithCallbackWrite8bitUnits ?? formerly jump to 0
0x02 swiDecompressLZSSwithCallbackWrite16bitUnits ?? formerly jump to 0
0x03 swiWaitByLoop ?? same as DS
0x04 swiIntrWait ?? same as DS (but bugged? see note)
0x05 swiVBlankIntrWait ?? same as DS (but bugged? see note)
0x06 swiHalt ?? same as DS
0x07-0x08 N/A (hangs) ?? same as DS / formerly jump to 0
0x09 swiDivide ?? same as DS
0x0A N/A (hangs) ?? same as DS / formerly jump to 0
0x0B swiCopy ?? same as DS
0x0C swiFastCopy ?? same as DS
0x0D swiSqrt ?? same as DS
0x0E swiCRC16 ?? same as DS
0x0F N/A (hangs) ?? formerly IsDebugger
0x10 swiUnpackBits ?? same as DS
0x11 swiDecompressLZSSWram ?? same as DS
0x12 N/A (ignored) ?? (formerly swiDecompressLZSSVram)
0x13 swiDecompressHuffmanWithCallbackWrite32bitUnits ?? same as DS
0x14 swiDecompressRLEWram ?? same as DS
0x15 swiDecompressRLEwithCallbackWrite16bitUnits ?? same as DS
0x16 swiDecodeDelta8 ?? same as DS
0x17 N/A (hangs) ?? same as DS / formerly jump to 0
0x18 swiDecodeDelta16 ?? same as DS
0x19 swiDecompressLZSSwithCallbackWrite16bitUnits ?? same as SWI 0x02 / formerly jump to 0
0x1A-0x1E N/A (hangs) ?? same as DS / formerly jump to 0
0x1F swiCustomPost ?? same as DS
0x20 swiInit_crypto_heap ?? new
0x21 swiRSA_decrypt ?? new
0x22 swiRSA_decrypt_signature ?? new
0x23 swiRSA_decrypt_der ?? new
0x24 swiSHA1_Init ?? new
0x25 swiSHA1_Update ?? new
0x26 swiSHA1_Final ?? new
0x27 swiSHA1 ?? new
0x28 swiSHA1_Compare ?? new
0x29 swiSHA1_Random looks like it's trying to generate a random number using SHA1 new
0x2A N/A (hangs) ?? formerly jump to garbage
0x2B N/A (ignored) ?? formerly jump to garbage
0x2C-0x3F N/A (hangs) ?? formerly jump to garbage
0x40-0xFF Mirrors of 0x00-0x3F ?? formerly jump to garbage

The two ignored function do return without doing anything (they are rejected before calling the SWI function table). The other unused functions do hang in an endless loop.

Note: swiHalt does correctly use CP15 to halt the ARM9 processor. But, swiVBlankIntrWait and swiIntrWait do use port 0x4000301 (which would be correct on ARM7, unknown if the same mechanism is actually supported on ARM9, if it isn't supported then the functions would more or less behave as desired - wait for IRQ flags to get set - but without actually switching the CPU into low-power mode).

See Also