Here is one in plain 68000 assembler. move.b #200,d0 move.b #100,d1 add.b d0,d1 ; 8th bit goes to X flag subx.b d0,d0 ; d0 = $00 or $ff depending

Here is one in plain 68000 assembler. move.b #200,d0 move.b #100,d1 add.b d0,d1 ; 8th bit goes to X flag subx.b d0,d0 ; d0 = $00 or $ff depending on X flag or.b d0,d1 ; d1 = 255 if there was saturation You can do the same with all others that somehow store the 8th bit carry somewhere then allow using it for substraction.