A = b = b = 32 32 - - bits bits a * b = (a, 16 + a, 16 + b – Vodafone SS 08 User Manual
Page 39: 32] + [(a, 16] + [(a, 16] + [a
TU Dresden, 4/29/2008
Slide 39
chair
Numerical Issues - 32-bit Multiplication
It is possible to perform 32-bit multiplication
using 16-bit multipliers.
Example: c = a x b (with 32-bit values).
a
a
h
h
a
a
l
l
b
b
h
h
b
b
l
l
a =
a =
b =
b =
32
32
-
-
bits
bits
a * b = (a
h
<< 16 + a
l
)* (b
h
<< 16 + b
l
)
= [(a
h
* b
h
) << 32] + [(a
l
* b
h
) << 16] +
[(a
h
* b
l
) << 16] + [a
l
* b
l
]