#include <stdint.h>

/*
Replace (f,g) with (g,f) if b == 1;
replace (f,g) with (f,g) if b == 0.

Preconditions: b in {0,1}.
*/

void fe_cswap(int32_t f[10], int32_t g[10], unsigned int b) {
	int32_t f0 = f[0];
	int32_t f1 = f[1];
	int32_t f2 = f[2];
	int32_t f3 = f[3];
	int32_t f4 = f[4];
	int32_t f5 = f[5];
	int32_t f6 = f[6];
	int32_t f7 = f[7];
	int32_t f8 = f[8];
	int32_t f9 = f[9];
	int32_t g0 = g[0];
	int32_t g1 = g[1];
	int32_t g2 = g[2];
	int32_t g3 = g[3];
	int32_t g4 = g[4];
	int32_t g5 = g[5];
	int32_t g6 = g[6];
	int32_t g7 = g[7];
	int32_t g8 = g[8];
	int32_t g9 = g[9];
	int32_t x0 = f0 ^ g0;
	int32_t x1 = f1 ^ g1;
	int32_t x2 = f2 ^ g2;
	int32_t x3 = f3 ^ g3;
	int32_t x4 = f4 ^ g4;
	int32_t x5 = f5 ^ g5;
	int32_t x6 = f6 ^ g6;
	int32_t x7 = f7 ^ g7;
	int32_t x8 = f8 ^ g8;
	int32_t x9 = f9 ^ g9;
	b = -b;
	x0 &= b;
	x1 &= b;
	x2 &= b;
	x3 &= b;
	x4 &= b;
	x5 &= b;
	x6 &= b;
	x7 &= b;
	x8 &= b;
	x9 &= b;
	f[0] = f0 ^ x0;
	f[1] = f1 ^ x1;
	f[2] = f2 ^ x2;
	f[3] = f3 ^ x3;
	f[4] = f4 ^ x4;
	f[5] = f5 ^ x5;
	f[6] = f6 ^ x6;
	f[7] = f7 ^ x7;
	f[8] = f8 ^ x8;
	f[9] = f9 ^ x9;
	g[0] = g0 ^ x0;
	g[1] = g1 ^ x1;
	g[2] = g2 ^ x2;
	g[3] = g3 ^ x3;
	g[4] = g4 ^ x4;
	g[5] = g5 ^ x5;
	g[6] = g6 ^ x6;
	g[7] = g7 ^ x7;
	g[8] = g8 ^ x8;
	g[9] = g9 ^ x9;
}