If you want to learn what’s in the system ROM then you must know H.-G. Schliecker publications !
Do you remember the “PC-1500 INTERN” with the whole disassembled and commented ROM ?
Today i have something all the assembly language programmers are dreaming to :
“SHARP PC-1500 ROM Unterprogramme I“. When learning machine language programming you discover that there are 128 system routines you can directly call by short instructions. For example, some ones can handle Basic tokens and their parameters, others can execute mathematical calculations on real numbers…
But who knows all the 128 routines ?
This very rare paper describe all of them with calling parameters but it’s in German language 😉
As it’s named “ROM-Unterprogramme I” i suppose that a number II exists somewhere…
Maybe one of you can help me to find it ?