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      1 /*
      2  * Utility compute operations used by translated code.
      3  *
      4  * Copyright (c) 2003 Fabrice Bellard
      5  * Copyright (c) 2007 Aurelien Jarno
      6  *
      7  * Permission is hereby granted, free of charge, to any person obtaining a copy
      8  * of this software and associated documentation files (the "Software"), to deal
      9  * in the Software without restriction, including without limitation the rights
     10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     11  * copies of the Software, and to permit persons to whom the Software is
     12  * furnished to do so, subject to the following conditions:
     13  *
     14  * The above copyright notice and this permission notice shall be included in
     15  * all copies or substantial portions of the Software.
     16  *
     17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
     20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
     23  * THE SOFTWARE.
     24  */
     25 
     26 #include <stdlib.h>
     27 #include <stdint.h>
     28 #include "qemu/host-utils.h"
     29 
     30 /* Long integer helpers */
     31 #ifndef CONFIG_INT128
     32 static inline void mul64(uint64_t *plow, uint64_t *phigh,
     33                          uint64_t a, uint64_t b)
     34 {
     35     typedef union {
     36         uint64_t ll;
     37         struct {
     38 #ifdef HOST_WORDS_BIGENDIAN
     39             uint32_t high, low;
     40 #else
     41             uint32_t low, high;
     42 #endif
     43         } l;
     44     } LL;
     45     LL rl, rm, rn, rh, a0, b0;
     46     uint64_t c;
     47 
     48     a0.ll = a;
     49     b0.ll = b;
     50 
     51     rl.ll = (uint64_t)a0.l.low * b0.l.low;
     52     rm.ll = (uint64_t)a0.l.low * b0.l.high;
     53     rn.ll = (uint64_t)a0.l.high * b0.l.low;
     54     rh.ll = (uint64_t)a0.l.high * b0.l.high;
     55 
     56     c = (uint64_t)rl.l.high + rm.l.low + rn.l.low;
     57     rl.l.high = c;
     58     c >>= 32;
     59     c = c + rm.l.high + rn.l.high + rh.l.low;
     60     rh.l.low = c;
     61     rh.l.high += (uint32_t)(c >> 32);
     62 
     63     *plow = rl.ll;
     64     *phigh = rh.ll;
     65 }
     66 
     67 /* Unsigned 64x64 -> 128 multiplication */
     68 void mulu64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
     69 {
     70     mul64(plow, phigh, a, b);
     71 }
     72 
     73 /* Signed 64x64 -> 128 multiplication */
     74 void muls64 (uint64_t *plow, uint64_t *phigh, int64_t a, int64_t b)
     75 {
     76     uint64_t rh;
     77 
     78     mul64(plow, &rh, a, b);
     79 
     80     /* Adjust for signs.  */
     81     if (b < 0) {
     82         rh -= a;
     83     }
     84     if (a < 0) {
     85         rh -= b;
     86     }
     87     *phigh = rh;
     88 }
     89 #endif /* !CONFIG_INT128 */
     90