SU1297039A1 - Device for calculating function values - Google Patents

Abstract

The invention permits the computation of floating point functions using the computation of an auxiliary function with a fixed comma. Objectives f (x) where (x) is the calculation of the invention — the simplification of the device is achieved by calculating the function (x X is fixed, and Cf (x) is floating point. The proposed device contains a dividing unit 1 2, counter 3, subtractor 4, memory block 5, which stores the values of the cp (x) xf (x) fixed-point function, denormalizer 6, block 7, the calculation of the mantissa module. This device can & It is made in the form of a single large integrated circuit and is used as a functional expander of the central process. ra computer 1. i. (L

Description

1 .1297039

The invention relates to computing and can be used in the construction of functional expanders of electronic computers of various classes and purposes.

The aim of the invention is to simplify the device.

Calculation of the function f (x) with floating2

Talet 4, memory block 5, denormal mash 6, block 7 calculating the module of the argument mantissa. The inputs of the 8th order of the argument are connected to the information inverse inputs of the counter 3, and the outputs are the outputs of the 9th order.

result, and to the control inputs

denormalizer 6. Inputs 10 of the mantis sy argument are connected to the information

a comma is achieved by using the inputs of block 7 by calculating the calculation in a function block (in the simplest case, a memory sample) of the function (| (x) x f (x) with after ...-. Cf (x) following calculating g (.x;

At j5

the module of the mantissa and with the inputs of the division of the division unit 1, and the input 11 of the symbol of the argument mantissa is connected to the input of the separator of the division unit 1 to the control input of the unit 7 for calculating the module of the argument mantissa.

This tf (x) is computed with a fixed, and f (x) with a floating point. Using this conversion to play: floating point function definitions are effectively applied to odd functions represented by the Taylor series of the form:

one

f (x) - (a, x + a

 +, ..)

This is true, in particular, for the functions ctg (x), cth (x), etc.

For argument values x, represented in floating point form xxx 2, in the range X in (2, / 4), the argument order is Pj, 1, N, when calculating f (x) ctgx in functionality: Nom block is calculated Cf , (x) x-ctg X with fixed comma, since c (x) e (T / 4, 1), and the result f, (x) cf, (x) / x is floating-point. Similarly, f (x) cth (x), X e (, 1), as well as other functions of this type, for example, are also calculated.

1 L + 1% in ().

Thus, a new method for calculating floating-point functions is proposed, which consists in calculating the auxiliary function cp (x) x-f (x) with a fixed comma and then calculating the ratio

f (x)

(p (x)

- and a device that implements 50

g

this way. Usually, direct calculation of f (x) with a floating point is used to perform many operations with a floating point.

The drawing shows a block diagram of the proposed device.

The device contains a block 1 division, sdzigatel 2, counter 3,

2

4, memory block 5, denormalizer 6, block 7, calculating the module of the argument mantissa. The 8-order inputs of the argument are connected to the information inverted inputs of counter 3, whose outputs are 9-order outputs.

result, and to the control inputs

denormalizer 6. The inputs 10 of the argument mantissa are connected to the informational inputs of block 7 of the calculation

on the inputs of the calculation block 7

the module of the mantissa and with the inputs of the divider of the division unit 1, and the input 11 of the symbol of the mantissa of the argument is connected to the input of the divider of the division unit 1 and to the control input of the unit 7 for calculating the module of the argument mantissa.

The proposed device works as follows.

The mantissa of argument x from inputs 10 goes to the information inputs of block 7 of the module calculation of the mantissa, in which the module of the mantissa sh is determined by the control of the sign bit of the mantissa of argument coming from input 11 (assumed mj (from inputs 10 is presented in the additional code The module of the mantissa from the outputs of block 7 is fed to the inputs of the decremented calculator 4 and to the information inputs of the denormalizer 6, in which under the control of order P

of argument x, the modulus of the mantissa is denormalized, i.e. The argument X at the output of the denormalizer 6 is represented in the firm with a fixed comma. This value x from the output of the denormalizer 6 is fed to the inputs of block 5, where the value of the function Cf (x) X f (x) is calculated with a fixed comma. From the output of block 5, the value of cp (x) is fed to the inputs of the shifter 2 and to the inputs of the subtractile subtractor 4, where the difference sign determines the value (} (x) is greater than or equal to the module mantissa / t;, /. , if (| (x) 5 then a signal is generated to increase the content of counter 3 by two (the additional unit takes additional code from the negative order of the argument to get the order of the function) and shifts the content of the shifter 2 by one bit to the right to ensure proper operation block 1 division (the dividend must be less than the divisor ), Since the module mantissa ap

3

of the argument does not come out (0.5: 1), and q (x) e (1G / 4, H (x) p I

Shu

sewing

e (0.5: 2). E

That is, only a signal to increase the content of counter 3 per unit is generated. From the outputs of the shifter 2, the value C (x) is fed to the input of the divisible block 1 of the dividend, to the input of the divider which receives the value of the mantissa of the argument m from inputs 10 and the sign of the mantissa from the input 11. As a result of the division at the outputs 12 of block 1, the value of the mantissa of the function f is obtained (x), and at outputs 9 of counter 3, the order value of the function f (x).

calculating the mantissa module of the argument The proposed device can be 20 connected to the information input on a series of microcircuits, namely division unit 1 (КР1802 ВР2), Shift 2 (К155 ИР1), counter 3 (К155 ИЕ7), subtractor 4 (К555СП1), function block 5 (K501 PE 1P or KP 556 PT4), denormalizer 6 (KP 1802 BP1), block 7 calculation of the mantissa module (K155 IE7).

the normalizer and the input of the decremented subtractor, the output of the denormalizer is connected to the address input of the memory unit, the output of which is connected to the input of the subtracted subtractor to the information input of the shifter, the output of which is connected to the input of the divisible division unit, the output of which is the output of the mantissa of the function setDornormalizer 6 real-30 solutions, information input is counted, for example, on the basis of Am25S10 microcircuits, the domestic analogue of the K531 IR il. With the appropriate connection, Ara25S10 can be used to shift any number of bits 35

The pin is connected to the control input of the denormalizer, the output of the sign subtractor is connected to the shift direction shift control input and to the counting counter input, the output of which is the output of the order of the device function.

to any number of bits right or left.

Compiled by Z. Shershneva Editor L. Povkhan Tehred M. Khodich Proofreader S. Cherni

Order 781/51 Circulation 673 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

Claims (1)

The invention of a function calculating device comprising a memory block, a subtractor, a counter, a shifter, wherein the information input of the counter is an input to the order of the device argument, characterized in that, in order to simplify the device, it contains a dividing unit, a denormalizer, the module for calculating the modulus of the argument's mantissa, whose information input is the input of the mantissa of the device argument and connected to the input of the divider of the divider, the control the input of the calculating unit of the argument mantissa module and the input of the sign of the divider of the division block are connected to the input of the sign of the argument of the device, the output of the block the normalizer and the input of the decremented subtractor, the output of the denormalizer is connected to the address input of the memory unit, the output of which is connected to the input of the subtracted subtractor to the information input of the shifter, the output of the truth, the information input of the counter- The key is connected to the control input of the denormalizer, the output of the sign bit of the subtractor is connected to the control input of the shift direction of the shift and with the counting input of the counter, the output of which is the output of the order of the device function.