math.c revision 1.1.1.1.2.2
1 1.1.1.1.2.2 pgoyette /* $NetBSD: math.c,v 1.1.1.1.2.2 2018/09/06 06:56:39 pgoyette Exp $ */ 2 1.1.1.1.2.2 pgoyette 3 1.1.1.1.2.2 pgoyette /* 4 1.1.1.1.2.2 pgoyette * Copright (C) 2014 Linaro Ltd. 5 1.1.1.1.2.2 pgoyette * Author: Ard Biesheuvel <ard.biesheuvel (at) linaro.org> 6 1.1.1.1.2.2 pgoyette * 7 1.1.1.1.2.2 pgoyette * Redistribution and use in source and binary forms, with or without 8 1.1.1.1.2.2 pgoyette * modification, are permitted provided that the following conditions 9 1.1.1.1.2.2 pgoyette * are met: 10 1.1.1.1.2.2 pgoyette * 1. Redistributions of source code must retain the above copyright 11 1.1.1.1.2.2 pgoyette * notice and this list of conditions, without modification. 12 1.1.1.1.2.2 pgoyette * 2. The name of the author may not be used to endorse or promote products 13 1.1.1.1.2.2 pgoyette * derived from this software without specific prior written permission. 14 1.1.1.1.2.2 pgoyette * 15 1.1.1.1.2.2 pgoyette * Alternatively, this software may be distributed under the terms of the 16 1.1.1.1.2.2 pgoyette * GNU General Public License as published by the Free Software Foundation; 17 1.1.1.1.2.2 pgoyette * either version 2 of the License, or (at your option) any later version. 18 1.1.1.1.2.2 pgoyette */ 19 1.1.1.1.2.2 pgoyette 20 1.1.1.1.2.2 pgoyette #include "lib.h" 21 1.1.1.1.2.2 pgoyette 22 1.1.1.1.2.2 pgoyette UINT64 23 1.1.1.1.2.2 pgoyette LShiftU64 ( 24 1.1.1.1.2.2 pgoyette IN UINT64 Operand, 25 1.1.1.1.2.2 pgoyette IN UINTN Count 26 1.1.1.1.2.2 pgoyette ) 27 1.1.1.1.2.2 pgoyette // Left shift 64bit by 32bit and get a 64bit result 28 1.1.1.1.2.2 pgoyette { 29 1.1.1.1.2.2 pgoyette return Operand << Count; 30 1.1.1.1.2.2 pgoyette } 31 1.1.1.1.2.2 pgoyette 32 1.1.1.1.2.2 pgoyette UINT64 33 1.1.1.1.2.2 pgoyette RShiftU64 ( 34 1.1.1.1.2.2 pgoyette IN UINT64 Operand, 35 1.1.1.1.2.2 pgoyette IN UINTN Count 36 1.1.1.1.2.2 pgoyette ) 37 1.1.1.1.2.2 pgoyette // Right shift 64bit by 32bit and get a 64bit result 38 1.1.1.1.2.2 pgoyette { 39 1.1.1.1.2.2 pgoyette return Operand >> Count; 40 1.1.1.1.2.2 pgoyette } 41 1.1.1.1.2.2 pgoyette 42 1.1.1.1.2.2 pgoyette 43 1.1.1.1.2.2 pgoyette UINT64 44 1.1.1.1.2.2 pgoyette MultU64x32 ( 45 1.1.1.1.2.2 pgoyette IN UINT64 Multiplicand, 46 1.1.1.1.2.2 pgoyette IN UINTN Multiplier 47 1.1.1.1.2.2 pgoyette ) 48 1.1.1.1.2.2 pgoyette // Multiply 64bit by 32bit and get a 64bit result 49 1.1.1.1.2.2 pgoyette { 50 1.1.1.1.2.2 pgoyette return Multiplicand * Multiplier; 51 1.1.1.1.2.2 pgoyette } 52 1.1.1.1.2.2 pgoyette 53 1.1.1.1.2.2 pgoyette UINT64 54 1.1.1.1.2.2 pgoyette DivU64x32 ( 55 1.1.1.1.2.2 pgoyette IN UINT64 Dividend, 56 1.1.1.1.2.2 pgoyette IN UINTN Divisor, 57 1.1.1.1.2.2 pgoyette OUT UINTN *Remainder OPTIONAL 58 1.1.1.1.2.2 pgoyette ) 59 1.1.1.1.2.2 pgoyette { 60 1.1.1.1.2.2 pgoyette /* 61 1.1.1.1.2.2 pgoyette * GCC turns a division into a multiplication and shift with precalculated 62 1.1.1.1.2.2 pgoyette * constants if the divisor is constant and the dividend fits into a 32 bit 63 1.1.1.1.2.2 pgoyette * variable. Otherwise, it will turn this into calls into the 32-bit div 64 1.1.1.1.2.2 pgoyette * library functions. 65 1.1.1.1.2.2 pgoyette */ 66 1.1.1.1.2.2 pgoyette if (Remainder) 67 1.1.1.1.2.2 pgoyette *Remainder = Dividend % Divisor; 68 1.1.1.1.2.2 pgoyette return Dividend / Divisor; 69 1.1.1.1.2.2 pgoyette } 70
Indexes created Tue Sep 30 20:09:53 GMT 2025