libgcc/config/riscv/muldi3.S

   1 /* Integer multiplication routines for RISC-V.
   2
   3    Copyright (C) 2016-2018 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 Under Section 7 of GPL version 3, you are granted additional
  18 permissions described in the GCC Runtime Library Exception, version
  19 3.1, as published by the Free Software Foundation.
  20
  21 You should have received a copy of the GNU General Public License and
  22 a copy of the GCC Runtime Library Exception along with this program;
  23 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 <http://www.gnu.org/licenses/>.  */
  25
  26 #include "riscv-asm.h"
  27
  28   .text
  29   .align 2
  30
  31 #if __riscv_xlen == 32
  32 /* Our RV64 64-bit routine is equivalent to our RV32 32-bit routine.  */
  33 # define __muldi3 __mulsi3
  34 #endif
  35
  36 FUNC_BEGIN (__muldi3)
  37   mv     a2, a0
  38   li     a0, 0
  39 .L1:
  40   andi   a3, a1, 1
  41   beqz   a3, .L2
  42   add    a0, a0, a2
  43 .L2:
  44   srli   a1, a1, 1
  45   slli   a2, a2, 1
  46   bnez   a1, .L1
  47   ret
  48 FUNC_END (__muldi3)