kernel / pub / scm / linux / kernel / git / kdave / linux / 899537b73557aafbdd11050b501cf54b4f5c45af / . / lib / muldi3.c

/* | |

* 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> | |

#include <linux/libgcc.h> | |

#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); |