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:
34 #if !defined(_SDCC_NO_ASM_LIB_FUNCS)
39 _mulint (int a, int b)
41 a,b; /* reference to make compiler happy */
43 #if !defined(SDCC_STACK_AUTO)
104 struct { unsigned char hi,lo ;} s;
109 _mulint (int a, int b)
111 #if !defined(SDCC_STACK_AUTO) && (defined(SDCC_MODEL_LARGE) || defined(SDCC_ds390)) // still needed for large
115 x = (union uu __xdata *)&a;
116 y = (union uu __xdata *)&b;
118 register union uu *x;
119 register union uu *y;
125 t.t = x->s.lo * y->s.lo;
126 t.s.hi += (x->s.lo * y->s.hi) + (x->s.hi * y->s.lo);