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/*
* u128.c - 128 bit integer operations
*
* Written 2002 by Werner Almesberger
* Copyright 2002 Bivio Networks
*/
#include "u128.h"
/* ----- Basic 128 bit operations ------------------------------------------ */
U128 u128_add(U128 a,U128 b)
{
int i,carry = 0;
for (i = 0; i < 4; i++) {
if (carry) {
a.v[i]++;
carry = a.v[i] == 0;
}
a.v[i] += b.v[i];
if (a.v[i] < b.v[i]) carry = 1;
}
return a;
}
U128 u128_sub(U128 a,U128 b)
{
int i,borrow = 0;
for (i = 0; i < 4; i++) {
if (borrow) {
borrow = !a.v[i];
a.v[i]--;
}
if (a.v[i] < b.v[i]) borrow = 1;
a.v[i] -= b.v[i];
}
return a;
}
U128 u128_minus(U128 a)
{
int i,carry = 1;
for (i = 0; i < 4; i++) {
a.v[i] = ~a.v[i];
if (carry) {
a.v[i]++;
carry = a.v[i] == 0;
}
}
return a;
}
U128 u128_and(U128 a,U128 b)
{
int i;
for (i = 0; i < 4; i++)
a.v[i] &= b.v[i];
return a;
}
U128 u128_or(U128 a,U128 b)
{
int i;
for (i = 0; i < 4; i++)
a.v[i] |= b.v[i];
return a;
}
U128 u128_xor(U128 a,U128 b)
{
int i;
for (i = 0; i < 4; i++)
a.v[i] ^= b.v[i];
return a;
}
U128 u128_not(U128 a)
{
int i;
for (i = 0; i < 4; i++)
a.v[i] = ~a.v[i];
return a;
}
U128 u128_shift_left(U128 a,uint32_t b)
{
int words,bits,i;
words = b/32;
bits = b % 32;
for (i = 3; i >= words; i--) {
a.v[i] = a.v[i-words] << bits;
if (bits && i > words) a.v[i] |= a.v[i-words-1] >> (32-bits);
}
while (i >= 0)
a.v[i--] = 0;
return a;
}
U128 u128_shift_right(U128 a,uint32_t b)
{
int words,bits,i;
words = b/32;
bits = b % 32;
for (i = 0; i < 4-words; i++) {
a.v[i] = a.v[i+words] >> bits;
if (bits && i < 4-words-1) a.v[i] |= a.v[i+words+1] << (32-bits);
}
while (i < 4) a.v[i++] = 0;
return a;
}
/* ----- 128 bit and 32 bit mixed ------------------------------------------ */
U128 u128_from_32(uint32_t a)
{
U128 res;
res.v[0] = a;
res.v[1] = res.v[2] = res.v[3] = 0;
return res;
}
uint32_t u128_to_32(U128 a)
{
if (a.v[1] || a.v[2] || a.v[3])
u128_error_hook("128 bit value is too large for 32 bits");
return a.v[0];
}
int u128_is_32(U128 a)
{
return !a.v[1] && !a.v[2] && !a.v[3];
}
U128 u128_add_32(U128 a,uint32_t b)
{
a.v[0] += b;
if (a.v[0] < b)
if (!++a.v[1])
if (!++a.v[2]) a.v[3]++;
return a;
}
U128 u128_sub_32(U128 a,uint32_t b)
{
int i;
if (a.v[0] < b)
for (i = 1; i < 4; i++)
if (a.v[i]--) break;
a.v[0] -= b;
return a;
}
U128 u128_sub_from_32(uint32_t a,U128 b)
{
return u128_add_32(u128_minus(b),a);
}
U128 u128_and_32(U128 a,uint32_t b)
{
a.v[0] &= b;
return a;
}
U128 u128_or_32(U128 a,uint32_t b)
{
a.v[0] |= b;
return a;
}
U128 u128_xor_32(U128 a,uint32_t b)
{
a.v[0] ^= b;
return a;
}
/* ----- Miscellaneous operations ------------------------------------------ */
int u128_cmp(U128 a,U128 b)
{
int i;
for (i = 0; i < 4; i++)
if (a.v[i] != b.v[i]) return a.v[i] < b.v[i] ? -1 : 1;
return 0;
}
int u128_is_zero(U128 a)
{
int i;
for (i = 0; i < 4; i++)
if (a.v[i]) return 0;
return 1;
}
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