void fb_mul_basic(fb_t c, const fb_t a, const fb_t b) { int i; dv_t s; fb_t t; dv_null(s); fb_null(t); TRY { /* We need a temporary variable so that c can be a or b. */ fb_new(t); dv_new(s); fb_zero(t); dv_zero(s + FB_DIGS, FB_DIGS); fb_copy(s, b); if (a[0] & 1) { fb_copy(t, b); } for (i = 1; i < FB_BITS; i++) { /* We are already shifting a temporary value, so this is more efficient * than calling fb_lsh(). */ s[FB_DIGS] = fb_lsh1_low(s, s); fb_rdc(s, s); if (fb_get_bit(a, i)) { fb_add(t, t, s); } } if (fb_bits(t) > FB_BITS) { fb_poly_add(c, t); } else { fb_copy(c, t); } } CATCH_ANY { THROW(ERR_CAUGHT); } FINALLY { fb_free(t); fb_free(s); } }
void fb_poly_sub(fb_t c, fb_t a) { fb_poly_add(c, a); }
void fb_poly_sub(fb_t c, const fb_t a) { fb_poly_add(c, a); }