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tmuldiv.3 (640B)
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1 .TH MULDIV 3
2 .SH NAME
3 muldiv, umuldiv \- high-precision multiplication and division
4 .SH SYNOPSIS
5 .B #include <u.h>
6 .br
7 .B #include <libc.h>
8 .PP
9 .B
10 long muldiv(long a, long b, long c)
11 .PP
12 .B
13 ulong umuldiv(ulong a, ulong b, ulong c)
14 .SH DESCRIPTION
15 .I Muldiv
16 returns
17 .BR a*b/c ,
18 using a
19 .B vlong
20 to hold the intermediate result.
21 .I Umuldiv
22 is the equivalent for unsigned integers.
23 They can be used to scale integer values without worry about
24 overflowing the intermediate result.
25 .PP
26 On some architectures, these routines can generate a trap if the
27 final result does not fit in a
28 .B long
29 or
30 .BR ulong ;
31 on others they will silently truncate.