sub_n.c

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/*
 * LAMMP - Copyright (C) 2025-2026 HJimmyK(Jericho Knox)
 * This file is part of lammp, under the GNU LGPL v2 license.
 * See LICENSE in the project root for the full license text.
 */
 
#include "../../../include/lammp/lmmpn.h"
 
mp_limb_t lmmp_sub_nc_(mp_ptr dst, mp_srcptr numa, mp_srcptr numb, mp_size_t n, mp_limb_t c) {
    mp_size_t i = 0;
    mp_limb_t cy = c;
 
    for (; i + 4 <= n; i += 4) {
        mp_limb_t a0, b0, r0;
        mp_limb_t a1, b1, r1;
        mp_limb_t a2, b2, r2;
        mp_limb_t a3, b3, r3;
 
        a0 = numa[i + 0];
        b0 = numb[i + 0];
 
        a1 = numa[i + 1];
        b1 = numb[i + 1];
 
        a2 = numa[i + 2];
        b2 = numb[i + 2];
 
        a3 = numa[i + 3];
        b3 = numb[i + 3];
 
        b0 += cy;
        cy = (b0 < cy);
        cy += (a0 < b0);
        r0 = a0 - b0;
 
        b1 += cy;
        cy = (b1 < cy);
        cy += (a1 < b1);
        r1 = a1 - b1;
 
        b2 += cy;
        cy = (b2 < cy);
        cy += (a2 < b2);
        r2 = a2 - b2;
 
        b3 += cy;
        cy = (b3 < cy);
        cy += (a3 < b3);
        r3 = a3 - b3;
 
        dst[i + 0] = r0;
        dst[i + 1] = r1;
        dst[i + 2] = r2;
        dst[i + 3] = r3;
    }
 
    for (; i < n; i++) {
        mp_limb_t a, b;
        a = numa[i];
        b = numb[i];
        b += cy;
        cy = (b < cy);
        cy += (a < b);
        dst[i] = a - b;
    }
 
    return cy;
}
 
mp_limb_t lmmp_sub_n_(mp_ptr dst, mp_srcptr numa, mp_srcptr numb, mp_size_t n) {
    mp_size_t i = 0;
    mp_limb_t cy = 0;
 
    for (; i + 4 <= n; i += 4) {
        mp_limb_t a0, b0, r0;
        mp_limb_t a1, b1, r1;
        mp_limb_t a2, b2, r2;
        mp_limb_t a3, b3, r3;
 
        a0 = numa[i + 0];
        b0 = numb[i + 0];
 
        a1 = numa[i + 1];
        b1 = numb[i + 1];
 
        a2 = numa[i + 2];
        b2 = numb[i + 2];
 
        a3 = numa[i + 3];
        b3 = numb[i + 3];
 
        b0 += cy;
        cy = (b0 < cy);
        cy += (a0 < b0);
        r0 = a0 - b0;
 
        b1 += cy;
        cy = (b1 < cy);
        cy += (a1 < b1);
        r1 = a1 - b1;
 
        b2 += cy;
        cy = (b2 < cy);
        cy += (a2 < b2);
        r2 = a2 - b2;
 
        b3 += cy;
        cy = (b3 < cy);
        cy += (a3 < b3);
        r3 = a3 - b3;
 
        dst[i + 0] = r0;
        dst[i + 1] = r1;
        dst[i + 2] = r2;
        dst[i + 3] = r3;
    }
 
    for (; i < n; i++) {
        mp_limb_t a, b;
        a = numa[i];
        b = numb[i];
        b += cy;
        cy = (b < cy);
        cy += (a < b);
        dst[i] = a - b;
    }
 
    return cy;
}