Fixed Point decimal complement one-digit multiplication (Booth comparison method)

Program:

// Fixed point decimal complement one-digit multiplication (Booth comparison method) // http://blog.csdn.net/justme0#define _ crt_secure_no_warnings # include <iostream> # include <bitset> # include <string> using namespace STD; const int N = 4; // number of digits // a, B Union right shift (arithmetic shift) void rightmove (bitset <n + 2> &, bitset <n + 1> & B, bool & ebit) {ebit = B [0]; B> = 1; B [N] = A [0]; a> = 1; A [n + 1] = A [n]; // arithmetic right shift} bitset <n + 2> operator + (bitset <n + 2>, bitset <n + 2> B) // evaluate the arithmetic sum of A and B and {return. To_ullong () + B. to_ullong ();} bitset <n + 2> operator-(bitset <n + 2> A, bitset <n + 2> B) {return. to_ullong ()-B. to_ullong ();} bitset <n + 1> getcomplement (bitset <n + 1> A) {if (a [n]) {A = ~ A. to_ullong () + 1;. set (n); // note} return a;} bitset <2 * n + 1> getcomplement (const bitset <n + 2> high, const bitset <n + 1> LOW) // The low bitwise discard, because it does not belong to the product, but the symbol of the original multiplier {bitset <2 * n + 1> ans (High. to_string (). substr (1) + low. to_string (). substr (0, 4); If (ANS [2 * n]) {ans = ~ Ans. to_ullong () + 1; ans. set (2 * n); // note} return ans;} Enum sign {_ 00, _ 01, _ 10, _ 11}; Sign Test (bool a, bool B) {If (! A &&! B) {return _ 00;} else if (! A & B) {return _ 01;} else if (&&! B) {return _ 10;} else // If (A & B) // all paths must return the value {return _ 11 ;}} bitset <2 * n + 1> complementonemul (const bitset <n + 1> X, const bitset <n + 1> Y) // transmits the bitset to the multiplier X and the multiplier y (original code representation) {bitset <n + 2> A; // A places partial product (the last is the high point of the product) bitset <n + 2> TMP = getcomplement (X ). to_ullong (); TMP [n + 1] = TMP [N]; // note the const bitset extension of the maximum bit of the complement Code <n + 2> B (TMP ); // B is the complement code of X. // you cannot use the different return values and overload them. Therefore, tmpbitset <n + 1> C = getcomplement (Y) is introduced. // C is y0.y1y2... YN (Y's complement) int CD = N + 1; // CD is the counter bool yn1 = 0; # pragma region core algorithm while (CD --) {Switch (test (C [0], yn1 )) // detect Y (I + 1)-y (I) {Case _ 00: Case _ 11: break; Case _ 10: A = A-B; break; case _ 01: A = a + B; break; default: break;} If (CD! = 0) // last non-shift {rightmove (A, C, yn1); // a, c union right shift, c down to yn1 }}# Pragma endregion core algorithm return getcomplement (a, c);} bitset <2 * n + 1> directmul (const bitset <n + 1> X, const bitset <n + 1> Y) {const bitset <n> X (X. to_ullong (); // returns the absolute value const bitset by truncating the high value. <n> Y (Y. to_ullong (); bitset <2 * n + 1> ans (X. to_ullong () * Y. to_ullong (); ans [2 * n] = x [N] ^ y [N]; // return ans;} int main (INT argc, char ** argv) {// freopen ("cin.txt", "r", stdin); string inputstrx; string inputstry; while (CIN> inputstrx> inputstry) {const bitset <n + 1> X (inputstrx); // X is the multiplier const bitset <n + 1> Y (inputstry ); // y is the cout multiplier <"complementonemul: \ t" <x <"*" <Y <"=" <complementonemul (x, y) <Endl; cout <"directmul: \ t" <x <"*" <Y <"=" <directmul (x, y) <Endl;} return 0 ;}

Running result: