Eric Lee / smarc-fsl-linux-kernel

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lib/muldi3.c 2.29 KB
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b35cd9884   Palmer Dabbelt   lib: Add shared c... 
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  /*
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, see the file COPYING, or write
   * to the Free Software Foundation, Inc.
   */
  
  #include <linux/export.h>
4db2b604c   Christoph Hellwig   move libgcc.h to ... 
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  #include <linux/libgcc.h>
b35cd9884   Palmer Dabbelt   lib: Add shared c... 
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  #define W_TYPE_SIZE 32
  
  #define __ll_B ((unsigned long) 1 << (W_TYPE_SIZE / 2))
  #define __ll_lowpart(t) ((unsigned long) (t) & (__ll_B - 1))
  #define __ll_highpart(t) ((unsigned long) (t) >> (W_TYPE_SIZE / 2))
  
  /* If we still don't have umul_ppmm, define it using plain C.  */
  #if !defined(umul_ppmm)
  #define umul_ppmm(w1, w0, u, v)						\
  	do {								\
  		unsigned long __x0, __x1, __x2, __x3;			\
  		unsigned short __ul, __vl, __uh, __vh;			\
  									\
  		__ul = __ll_lowpart(u);					\
  		__uh = __ll_highpart(u);				\
  		__vl = __ll_lowpart(v);					\
  		__vh = __ll_highpart(v);				\
  									\
  		__x0 = (unsigned long) __ul * __vl;			\
  		__x1 = (unsigned long) __ul * __vh;			\
  		__x2 = (unsigned long) __uh * __vl;			\
  		__x3 = (unsigned long) __uh * __vh;			\
  									\
  		__x1 += __ll_highpart(__x0); /* this can't give carry */\
  		__x1 += __x2; /* but this indeed can */			\
  		if (__x1 < __x2) /* did we get it? */			\
  		__x3 += __ll_B; /* yes, add it in the proper pos */	\
  									\
  		(w1) = __x3 + __ll_highpart(__x1);			\
  		(w0) = __ll_lowpart(__x1) * __ll_B + __ll_lowpart(__x0);\
  	} while (0)
  #endif
  
  #if !defined(__umulsidi3)
  #define __umulsidi3(u, v) ({				\
  	DWunion __w;					\
  	umul_ppmm(__w.s.high, __w.s.low, u, v);		\
  	__w.ll;						\
  	})
  #endif
  
  long long notrace __muldi3(long long u, long long v)
  {
  	const DWunion uu = {.ll = u};
  	const DWunion vv = {.ll = v};
  	DWunion w = {.ll = __umulsidi3(uu.s.low, vv.s.low)};
  
  	w.s.high += ((unsigned long) uu.s.low * (unsigned long) vv.s.high
  		+ (unsigned long) uu.s.high * (unsigned long) vv.s.low);
  
  	return w.ll;
  }
  EXPORT_SYMBOL(__muldi3);