Available Versions - Freescale Semiconductor DSP56800E User Manual

The MLIB_MulRnd
round method is the round to nearest. The function does not saturate the output. See the
following equation:

2.33.1 Available versions

This function is available in the following versions:
• Fractional output with fractional inputs - the output is the fractional portion of the
result; the result is within the range <-1 ; 1). The inputs are the fractional values only.
The result may overflow.
• Fractional output with mixed inputs - the output is the fractional portion of the result;
the result is within the range <-1 ; 1). The inputs are the accumulator and fractional
values. The result may overflow.
• Accumulator output - the output is the accumulator type where the result can be out
of the range <-1 ; 1). The result may overflow.
The available versions of the
Function name
MLIB_MulRnd_F16 frac16_t
MLIB_MulRnd_F16as acc32_t
MLIB_MulRnd_F32ls frac32_t
MLIB_MulRnd_F32 frac32_t
MLIB_MulRnd_A32 acc32_t
Freescale Semiconductor, Inc.
functions return the rounded product of two multiplicands. The
Equation 31. Algorithm formula
MLIB_MulRnd
Table 2-33. Function versions
Input type Result
type
Mult. 1 Mult. 2
frac16_t frac16_t
frac16_t frac16_t
frac16_t frac32_t
frac32_t frac32_t
acc32_t acc32_t
MLIB User's Guide, Rev. 2, 10/2015
function are shown in the following table:
Description
Product of two 16-bit fractional multiplicands; the output is
rounded to the upper 16 bits of the results [16..31]. The output
is within the range <-1 ; 1).
Product of a 32-bit accumulator and a 16-bit fractional
multiplicand; the output is a 16-bit fractional value, which is
rounded to the upper 16 bits of the fractional portion of the
result [16..31]. The output is within the range <-1 ; 1).
Product of a 32-bit and a 16-bit fractional multiplicand; the
output is rounded to the upper 32 bits of the fractional portion
of the result [16..47]. The output is within the range <-1 ; 1).
Product of two 32-bit fractional multiplicands; the output is
rounded to the upper 32 bits of the results [16..31]. The output
is within the range <-1 ; 1).
Product of two 32-bit accumulator multiplicands; the output is
rounded to the middle bits of the result [16..47]. The output is
within the range <-65536.0 ; 65536.0).
Chapter 2 Algorithms in detail
69