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1 | /* Multiplication two double word integers for RISC-V. |
2 | ||
99dee823 | 3 | Copyright (C) 2016-2021 Free Software Foundation, Inc. |
b8d7e076 KC |
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 "tconfig.h" | |
27 | #include "tsystem.h" | |
28 | #include "coretypes.h" | |
29 | #include "tm.h" | |
30 | #include "libgcc_tm.h" | |
31 | #define LIBGCC2_UNITS_PER_WORD (__riscv_xlen / 8) | |
32 | ||
33 | #include "libgcc2.h" | |
34 | ||
35 | #if __riscv_xlen == 32 | |
36 | /* Our RV64 64-bit routines are equivalent to our RV32 32-bit routines. */ | |
37 | # define __multi3 __muldi3 | |
38 | #endif | |
39 | ||
40 | DWtype | |
41 | __multi3 (DWtype u, DWtype v) | |
42 | { | |
43 | const DWunion uu = {.ll = u}; | |
44 | const DWunion vv = {.ll = v}; | |
45 | DWunion w; | |
46 | UWtype u_low = uu.s.low; | |
47 | UWtype v_low = vv.s.low; | |
48 | UWtype u_low_msb; | |
49 | UWtype w_low = 0; | |
50 | UWtype new_w_low; | |
51 | UWtype w_high = 0; | |
52 | UWtype w_high_tmp = 0; | |
53 | UWtype w_high_tmp2x; | |
54 | UWtype carry; | |
55 | ||
56 | /* Calculate low half part of u and v, and get a UDWtype result just like | |
57 | what __umulsidi3 do. */ | |
58 | do | |
59 | { | |
60 | new_w_low = w_low + u_low; | |
61 | w_high_tmp2x = w_high_tmp << 1; | |
62 | w_high_tmp += w_high; | |
63 | if (v_low & 1) | |
64 | { | |
65 | carry = new_w_low < w_low; | |
66 | w_low = new_w_low; | |
67 | w_high = carry + w_high_tmp; | |
68 | } | |
69 | u_low_msb = (u_low >> ((sizeof (UWtype) * 8) - 1)); | |
70 | v_low >>= 1; | |
71 | u_low <<= 1; | |
72 | w_high_tmp = u_low_msb | w_high_tmp2x; | |
73 | } | |
74 | while (v_low); | |
75 | ||
76 | w.s.low = w_low; | |
77 | w.s.high = w_high; | |
78 | ||
79 | if (uu.s.high) | |
80 | w.s.high = w.s.high + __muluw3(vv.s.low, uu.s.high); | |
81 | ||
82 | if (vv.s.high) | |
83 | w.s.high += __muluw3(uu.s.low, vv.s.high); | |
84 | ||
85 | return w.ll; | |
86 | } |