1 /*-------------------------------------------------------------------------
2 _mulint.c :- routine for (unsigned) int (16 bit) multiplication
4 Written By - Sandeep Dutta . sandeep.dutta@usa.net (1999)
6 This library is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Library General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
11 This library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU Library General Public License for more details.
16 You should have received a copy of the GNU Library General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20 In other words, you are welcome to use, share and improve this program.
21 You are forbidden to forbid anyone else to use, share and improve
22 what you give them. Help stamp out software-hoarding!
23 -------------------------------------------------------------------------*/
25 /* Signed and unsigned multiplication are the same - as long as the output
26 has the same precision as the input.
28 Assembler-functions are provided for:
31 mcs51 small stack-auto
37 struct { unsigned char hi,lo ;} s;
42 _mulint (int a, int b)
44 #if !defined(SDCC_STACK_AUTO) && (defined(SDCC_MODEL_LARGE) || defined(SDCC_ds390)) // still needed for large
48 x = (union uu xdata *)&a;
49 y = (union uu xdata *)&b;
58 t.t = x->s.lo * y->s.lo;
59 t.s.hi += (x->s.lo * y->s.hi) + (x->s.hi * y->s.lo);