#include "os.h"#include <mp.h>#include "dat.h" // prereq: a >= b, alen >= blen, diff has at least alen digitsvoidmpvecsub(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *diff){ int i, borrow; mpdigit x, y; borrow = 0; for(i = 0; i < blen; i++){ x = *a++; y = *b++; y += borrow; if(y < borrow) borrow = 1; else borrow = 0; if(x < y) borrow++; *diff++ = x - y; } for(; i < alen; i++){ x = *a++; y = x - borrow; if(y > x) borrow = 1; else borrow = 0; *diff++ = y; }}
#include "os.h"
#include <mp.h>
#include "dat.h"
// prereq: a >= b, alen >= blen, diff has at least alen digits
void
mpvecsub(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *diff)
{
int i, borrow;
mpdigit x, y;
borrow = 0;
for(i = 0; i < blen; i++){
x = *a++;
y = *b++;
y += borrow;
if(y < borrow)
borrow = 1;
else
borrow = 0;
if(x < y)
borrow++;
*diff++ = x - y;
}
for(; i < alen; i++){
x = *a++;
y = x - borrow;
if(y > x)
borrow = 1;
else
borrow = 0;
*diff++ = y;
}
}