/* Multiplication two double word integers for RISC-V. Copyright (C) 2016-2020 Free Software Foundation, Inc. This file is part of GCC. GCC 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 3, or (at your option) any later version. GCC 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. Under Section 7 of GPL version 3, you are granted additional permissions described in the GCC Runtime Library Exception, version 3.1, as published by the Free Software Foundation. You should have received a copy of the GNU General Public License and a copy of the GCC Runtime Library Exception along with this program; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see <http://www.gnu.org/licenses/>. */ #include "tconfig.h" #include "tsystem.h" #include "coretypes.h" #include "tm.h" #include "libgcc_tm.h" #define LIBGCC2_UNITS_PER_WORD (__riscv_xlen / 8) #include "libgcc2.h" #if __riscv_xlen == 32 /* Our RV64 64-bit routines are equivalent to our RV32 32-bit routines. */ # define __multi3 __muldi3 #endif DWtype __multi3 (DWtype u, DWtype v) { const DWunion uu = {.ll = u}; const DWunion vv = {.ll = v}; DWunion w; UWtype u_low = uu.s.low; UWtype v_low = vv.s.low; UWtype u_low_msb; UWtype w_low = 0; UWtype new_w_low; UWtype w_high = 0; UWtype w_high_tmp = 0; UWtype w_high_tmp2x; UWtype carry; /* Calculate low half part of u and v, and get a UDWtype result just like what __umulsidi3 do. */ do { new_w_low = w_low + u_low; w_high_tmp2x = w_high_tmp << 1; w_high_tmp += w_high; if (v_low & 1) { carry = new_w_low < w_low; w_low = new_w_low; w_high = carry + w_high_tmp; } u_low_msb = (u_low >> ((sizeof (UWtype) * 8) - 1)); v_low >>= 1; u_low <<= 1; w_high_tmp = u_low_msb | w_high_tmp2x; } while (v_low); w.s.low = w_low; w.s.high = w_high; if (uu.s.high) w.s.high = w.s.high + __muluw3(vv.s.low, uu.s.high); if (vv.s.high) w.s.high += __muluw3(uu.s.low, vv.s.high); return w.ll; } |