PM0014 datasheet(29/46 Pages) STMICROELECTRONICS

29 / 46 page

PM0014

Arithmetic library functions

29/46

5.5.4

cDiv_q31

cDiv_q31 (short LeftOpIMsb, short LeftOpILsb, short LeftOpRMsb, short LeftOpRLsb,

short RightOpIMsb, short RightOpILsb, short RightOpRMsb, short RightOpRLsb, long

*Output).

Description:

Division of two complex fractional inputs. Dividend, divisor and

quotient are on 64 bits (32 bits for each part).

Argument:

LeftOpIMsb

Left operand imaginary part most significant bits.

LeftOpILsb

Left operand imaginary part least significant bits.

LeftOpRMsb

Left operand real part most significant bits.

LeftOpRLsb

Left operand real part least significant bits.

RightOpIMsb Right operand imaginary part most significant bits.

RightOpILsb

Right operand imaginary part least significant bits.

RightOpRMsb Right operand real part most significant bits.

RightOpRLsb Right operand real part least significant bits.

Output

Output pointer.

Algorithm:

Note:

Output imaginary part is contained in the lowest addresses

(pointed by Output). Output real part is in the highest addresses

(pointed by Output + 4).

If c2 + d2 is equal to 0, result saturates to the maximum positive

value.

c2 + d2 must be smaller than the dividend real part and than the

dividend imaginary part for a valid result. Else, there is a result

saturation to the maximum positive or negative value.

If c2 + d2 and ac + bd (respectively c2 + d2 and bc - ad) are both a

maximum value. The result real part is not valid (respectively the

result imaginary part).

The implemented algorithm doesn’t allow integer division. For

dividing 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:

cDiv_q31.asm

Code size and cycles: Size: 442 bytes

Instruction cycles: 1148

aib

cid

--------------

--------------------i

–

-------------------

PM0014 Datenblatt(PDF) 29 Page - STMicroelectronics

PM0014 Datenblatt(HTML) 29 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46

Datenblatt Download

Link URL