Writing PSX Emu - help on proper I/O emulation

[Noplace]

Hi everyone,
will try to keep this brief, I've always wanted to make the 'perfect' playstation emulator where it would accurately emulate all the components, It's a long term project and I barely have the core ready(CPU,IO,Mem,loading bios and running,GPU but no graphics yet) hopefully ill reach there someday with your help

My current situation I'm trying to emulate the TTY so I can properly output the debug text without having to call putchar/etc on a bios call, based on docs( specially the new http://nocash.emubase.de/psx-spx.htm) I assumed during execution of the bios code it would attempt to write to the TTY ports, but alas in the disassembly debug output there are no such opcode calls.

Anyone can shed light on this situation, am I making sense to you? been reading the docs for years but never got around to applying, not an expert on opening up the hardware and doing the electronic testing and stuff, hoping that I can rely mostly on learning open source code, docs available online and trail and error.

This is only my first problem posted, many others to come :p
Thanks very much!