Scph1001 Bios =link= Link

The SCPH-1001 does include the “anti-modchip” code introduced in later BIOS revisions (which checks for secondary CD-ROM controller responses). As a result, early parallel port modchips function reliably. 5. BIOS Syscalls and Runtime Services The BIOS provides a set of 128 system calls ( syscall instruction) available to games. Key vectors for SCPH-1001:

| Syscall # | Function | Purpose | |-----------|----------|---------| | 0x00 | _Init | Initialize hardware | | 0x0B | _CdRead | Read CD-ROM sectors | | 0x0E | _Decode | MDEC video decode | | 0x32 | _GetVideoMode | Return NTSC/PAL detection | | 0x5C | _SetMem | Fast memory fill | scph1001 bios

| Feature | SCPH-1001 Implementation | |---------|--------------------------| | | Weak – only reads disc region string in TOC but does not enforce strict hardware lock. Many early swap-tricks work. | | Boot sector signature | Requires valid executable header (magic 0xFFFFFFFF at offset 0x10) but no encryption. | | Wobble groove detection | Not present. This was added in PU-18/PU-20 boards. | BIOS Syscalls and Runtime Services The BIOS provides