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PM0014

Arithmetic library functions

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5.5

Division

5.5.1

div_q31_q15_q15

div_q31_q15_q15 (short LeftOpMsb, short LeftOpLsb, short RightOp, short *Output).

Description:

Division of two real fractional inputs. Dividend is on 32 bits, divisor

on 16 bits and quotient on 16 bits.

Argument:

LeftOpMsb

Left operand most significant bits.

LeftOpLs

Left operand least significant bits.

RightOp

Right operand.

Output

Output pointer.

Algorithm:

LeftOp / RightOp = Output

Note:

The dividend must be smaller than the divisor for a valid result.

Divisions on limits (for example, division of 1 by 1 or of -1 by -1) are

not computed by this routine.

The algorithm implemented does not allow integer division. For

dividing two integers (dividend in 32.0 format and divisor in 16.0),

shift the dividend one bit to the left (into 31.1 format) before

dividing.

Assembly source

code:

div_q31_q15_q15.asm

Code size and cycles: Size: 98 bytes

Instruction cycles: 216

Test:

Two files are provided to test the function: an input vector file

(div_q31_q15_q15.in) and an output vector file

(div_q31_q15_q15.res):

div_q31_q15_q15.in is made as follows:

LeftOpMsb1, LeftOpLsb1, RightOp1

...

div_q31_q15_q15.res is made as follows:

Output1,

...

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