@Siva: Note that in 2-s complement arithmetic, -b = ~b + 1. So a - b = a + (-b) = a + (~b + 1) = (a + ~b) + 1. Thus, a - b can be written as
NOT B ADD A,B // reading this as add B to A, i.e., result is in A. ADD A,1 Dave On Sep 17, 11:15 am, siva viknesh <sivavikne...@gmail.com> wrote: > thanks a lot dave for clarification :) but this is there any > possibility to find max of 2 no.s using those instructions > alone(assuming contents of registers are +ve ) ? > > I found a solution finding difference of 2 no.s (SUB is required) and > checking for the whether a-b is +ve or -ve using '&' and SHR > operator....Is there any possibility with these instructions? > > On Sep 17, 9:08 pm, Dave <dave_and_da...@juno.com> wrote: > > > > > @Siva: The problem clearly states that we are "to find MAXINT - The > > maximum positive unsigned integer." It doesn't say that we are to find > > the maximum of any particular integers. In particular, it says that > > the initial contents of A and B are unknown, not that the initial > > contents are two integers that we are to find the greater of. > > > Dave > > > On Sep 17, 11:01 am, siva viknesh <sivavikne...@gmail.com> wrote: > > > > @dave .. I think we should find maximum of 2 no.s (present in 2 > > > registers)....plz provide solution for this...correct me if i m wrong > > > > On Sep 17, 8:50 pm, Dave <dave_and_da...@juno.com> wrote: > > > > > @Silva: > > > > > AND A,0 // sets register A to zero > > > > NOT A // complements all bits of A > > > > > The result is that A is filled with 1-bits, giving MAXINT. > > > > > Dave > > > > > On Sep 17, 6:06 am, siva viknesh <sivavikne...@gmail.com> wrote: > > > > > > Two registers A and B. Initial Contents of the registers are unknown. > > > > > Write a program to find MAXINT - The maximum positive unsigned integer > > > > > The instructions available are: > > > > > SHR reg1, op1 > > > > > ADD reg1, op1 > > > > > AND reg1, op1 > > > > > NOT reg1. > > > > > Op1 may represent any number or register. > > > > > (Hint: The Shift operation is a logical shift, not arithmetic shift.) > > > > > > ..solution plz .. i tried but unable to arrive- Hide quoted text - > > > > - Show quoted text -- Hide quoted text - > > - Show quoted text - -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to algogeeks@googlegroups.com. To unsubscribe from this group, send email to algogeeks+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
