utz82 / sc61860-instruction-set Goto Github PK

I believe that SR and SL instructions have incorrect description.
IMHO, the following is better:
SR : c->A7, A>>1, A0->c
SL: c->A0, A<<1. A7->c
The original descriptions are against the obvious logic used on most CPUs for rotation/shift operations.
They were probably copied without further verification from the first source link (but reformated, without correction of the error).
The proper functionality is demonstrated in your source link #5.
With regards, Pavel

Hello,
you write in the page readme

• 8 KB of integrated ROM at 0x0000-0x1FFF, cannot be read by user

this is not true. The DATA instruction OPcode 35H reads the data from the internal ROM when the address in AB is in the 0000-1FFF range

Thanks for the comprehensive overview of the SC61860 instructions!

There is a minor typo in this table, where Xh should be 0x05, Xl should be 0x04, Yh should be 0x07 and Yl should be 0x06:

It's confusing that the internal RAM 16 bit values for registers X and Y (and BA for DATA) are little endian when the external memory 16 bit values (such as LIDP, jump and call addresses) are big endian.