1/* Multiply a limb vector by a single limb, for PowerPC.
2 Copyright (C) 1993-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <sysdep.h>
20
21/* mp_limb_t mpn_submul_1 (mp_ptr res_ptr, mp_srcptr s1_ptr,
22 mp_size_t s1_size, mp_limb_t s2_limb)
23 Calculate res-s1*s2 and put result back in res; return carry. */
24
25ENTRY (__mpn_submul_1)
26 mtctr r5
27
28 lwz r0,0(r4)
29 mullw r7,r0,r6
30 mulhwu r10,r0,r6
31 lwz r9,0(r3)
32 subf r8,r7,r9
33 addc r7,r7,r8 # invert cy (r7 is junk)
34 addi r3,r3,-4 # adjust res_ptr
35 bdz L(1)
36
37L(0): lwzu r0,4(r4)
38 stwu r8,4(r3)
39 mullw r8,r0,r6
40 adde r7,r8,r10
41 mulhwu r10,r0,r6
42 lwz r9,4(r3)
43 addze r10,r10
44 subf r8,r7,r9
45 addc r7,r7,r8 # invert cy (r7 is junk)
46 bdnz L(0)
47
48L(1): stw r8,4(r3)
49 addze r3,r10
50 blr
51END (__mpn_submul_1)
52

source code of glibc/sysdeps/powerpc/powerpc32/submul_1.S