reg_ind
return reg_ind(reg, M_INDXY);
o = reg_ind(reg, M_INDEX);
operand reg_ind(int, int);
| '*' REGISTER '+' { $$ = reg_ind($2, M_POSTINC); }
| '*' '-' REGISTER { $$ = reg_ind($3, M_PREDEC); }
| '-' '*' REGISTER { $$ = reg_ind($3, M_PREDEC); }
| '*' REGISTER { $$ = reg_ind($2, M_IND); }