#include <stdio.h>





struct INT128 {
	unsigned char	i[16];
};





void right_shift_INT128(struct INT128* a, int b);
void left_shift_INT128(struct INT128* a, int b);





// INT128 ← char[16]
void write_INT128(struct INT128* d, unsigned char* s)
{
	unsigned char* p = d->i;
	int i=16; while(i-->0){ *p++ = *s++; }
}

// char[16] ← INT128
void read_INT128(struct INT128* s, unsigned char* d)
{
	unsigned char* p = s->i;
	int i=16; while(i-->0){ *d++ = *p++; }
}

// INT128 ← 0
void write_zero_INT128(struct INT128* d)
{
	unsigned char* p = d->i;
	int i=16; while(i-->0){ *p++ = 0; }
}




// a = a + b
void add_INT128(struct INT128* a, struct INT128* b)
{
	unsigned char* ap = a->i;
	unsigned char* bp = b->i;

	unsigned short c = 0;
	int i=16; while(i-->0){
		c = ((unsigned short)*ap) + ((unsigned short)*bp) + (c>>8);
		*ap = (unsigned char)c;

		ap++;
		bp++;
	}
}

// a = b
void mov_INT128(struct INT128* a,struct INT128* b)
{
int i;
       for(i=0;i<16;i++){ a->i[i] = b->i[i];}
}

// a = ~a
void not_INT128(struct INT128* a)
{
int i;
       for(i=0;i<16;i++){ a->i[i] = ~(a->i[i]);}
}

// a = a - b
void sub_INT128(struct INT128* a, struct INT128* b)
{
struct INT128 c;
struct INT128 const1={1};
       mov_INT128(&c,b);
       not_INT128(&c);
       add_INT128(&c,&const1);
       add_INT128(a,&c);
}

// a = a >> 1
void right_shift_1_INT128(struct INT128* a)
{
int i;
unsigned char c;
    for(i=16;i;)
    {
        i--;
        c=a->i[i]&1;
        a->i[i]/=2;
        if(i && c)
        {
            a->i[i-1]|=0x80;    
        }
    }
}

// a = a << 1
void left_shift_1_INT128(struct INT128* a)
{
int i;
unsigned char c=0,cc;
    for(i=0;i<16;i++)
    {
        i--;
        cc=(a->i[i]&0x80)/0x80;
        a->i[i]*=2;
        a->i[i]|=c;
        c=cc;
    }
}

// a = a * b
void mul_INT128(struct INT128* a, struct INT128* b)
{
	//
}

// a = a / b
void div_INT128(struct INT128* a, struct INT128* b)
{
	//
}

// a = a >> b
void right_shift_INT128(struct INT128* a, int b)
{
	if (b >= 128) { write_zero_INT128(a); return; }

	if (b < 0) { left_shift_INT128(a, -b); return; }
	
	
	unsigned char* p = a->i + (16 - 1);
	
	unsigned int segment = b / 8;
	unsigned int offset = b % 8;
	
	unsigned short c = 0;
	int i=16; while(i-->0){
		c = (((unsigned short)*p) << (8 - offset)) | (c << 8);
		*p-- = (unsigned char)(c >> 8);
	}
	
	
	unsigned char* sp = a->i + segment;
	unsigned char* dp = a->i;
	i = 16 - segment; while(i-->0){
		*dp++ = *sp++;
	}
	
	
	i = segment; while(i-->0){
		*dp++ = 0;
	}
}

// a = a << b
void left_shift_INT128(struct INT128* a, int b)
{
}

// a = a & b
void and_INT128(struct INT128* a, struct INT128* b)
{
int i=16;
    while(i--) { a->i[i]&=b->i[i];}
}

// a = a | b
void or_INT128(struct INT128* a, struct INT128* b)
{
int i=16;
    while(i--) { a->i[i]|=b->i[i];}
}

// a = a ^ b
void xor_INT128(struct INT128* a, struct INT128* b)
{
int i=16;
    while(i--) { a->i[i]^=b->i[i];}
}







void print_0x_INT128(struct INT128* a)
{
	printf("0x");

	unsigned char* p = a->i + (16 - 1);
	int i=16; while(i-->0){ printf("%02X", *p--); }
}





//test
void main()
{
	unsigned char c[16] = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160};

	struct INT128 a;	write_INT128(&a,c);
	struct INT128 b;	write_INT128(&b,c);
	
	
	// add test
	printf("add test\n");
	printf("a = ");		print_0x_INT128(&a);	printf("\n");
	printf("b = ");		print_0x_INT128(&b);	printf("\n");
	
	printf("a = a + b\n");
	add_INT128(&a,&b);
	
	printf("a = ");		print_0x_INT128(&a);	printf("\n");
	

	// right shift test
	int right_shift = 81;
	printf("right shift test\n");
	printf("a = ");		print_0x_INT128(&a);	printf("\n");
	printf("right shift = %d\n", right_shift);
			
	printf("a = a >> %d\n", right_shift);
	right_shift_INT128(&a, right_shift);
	
	printf("a = ");		print_0x_INT128(&a);	printf("\n");
	
	
}

add test
a = 0xA0968C82786E645A50463C32281E140A
b = 0xA0968C82786E645A50463C32281E140A
a = a + b
a = 0x412D1904F0DCC8B4A08C7864503C2814
right shift test
a = 0x412D1904F0DCC8B4A08C7864503C2814
right shift = 81
a = a >> 81
a = 0x0000000000000000000020968C82786E