JPH02197919A - Rotator and shifter dealing with different sizes - Google Patents

Abstract

PURPOSE:To obtain an excellent shifter which has a structure containing the constant bit width with high rule properties and is suited to an LSI by preparing an input data copying device and a rotator which performs the rotation with the fixed bit width. CONSTITUTION:A rotator contains an input data copying device 23 which copies the valid data on the LSB (lower rank) side to the MSB (higher rank) side based on the inputted data size, a rotator 28 which performs the rotation with the fixed width, and a shift amount qualifying device 25 which controls the rotator 28. In such a constitution, the valid data is copied to the MSB side and therefore this copied data is circulated to the LSB side from the MSB side. Thus the data can be rotated with use of the same hardware and the same control method regardless of the valid quantity of input data.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotator of different sizes that performs rotation by a rotator with a fixed bit width in an information processing device.

Also, using the different size rotators, rotate,
It is concerned with chics that perform logical shifts, arithmetic shifts, and mask operations.

Conventional technology A conventional rotator will be explained below.

FIG. 4 shows a conventional rotator.

In Fig. 4, 1 is the input data, 2 is the control line indicating the shift amount, 3 is the rotator, and internally there are 1 each of 4 to 8.
．． It consists of 2, 4, and 8.16 bit circulators, and rotates between 0 and 31 bits depending on the combination of each circulator.

9 is the output of the rotator.

The 1-bit configuration of each circulator is shown in FIG. 6(a).

10.11 is the input data or the output of the upper stage circulator, and the multiplexer 12 is instructed by the 130 control line whether or not to rotate that stage, selects 10.11, and gyrotates by 14. Outputs the rotated value or the value without rotation.

Problems to be Solved by the Invention However, with the above configuration, when the input data has a small number of effective bits compared to the bit width of each circulator, correct results cannot be obtained if the multiplexer of each circulator is operated by only two people. I can't get it.

In FIG. 4, the input data and the maximum bit width of each circulator are assumed to be 32 bits. . For this configuration, the valid number of bits of input data is 8 bits, and the MSB side is 24 bits.
Data with an undefined value in the pit (Figure 6) 15 is input, and if the n pit is rotated to the left, the output is 16, the undefined value on the MSB side is loaded to the LSB side, and the output is be done.

As mentioned above, in order to rotate data of a smaller size with respect to the bit width of the input data and the bit width of each circulator, each circulator should not be a two-man multiplexer like 12. However, since the multi-input multiplexer must correspond to the corresponding input data size, the number of gates and wiring increases.

The present invention solves the above-mentioned conventional problems, and aims to provide a rotator that can rotate data of different sizes without significantly increasing the hardware, and a chic device using the rotator. shall be.

Means for Solving the Problems To achieve this object, the rotator of the present invention converts valid data on the LSB side into MS, depending on the size of input data.
It has the configuration of an input data copying device for copying to the B side, a fixed rotator for rotating, and a shift amount modification device for controlling the rotator. Further, the shifter that performs a shift operation other than rotation has the configuration of the rotator corresponding to different sizes, a pattern generation device corresponding to the shift amount, and a logical operation device that performs a logical operation corresponding to the type of shift.

Effect With this configuration, valid data is copied to the MSB side, so the copied valid data is transferred from the MSB side to the LS
Regardless of the effective amount of input data that is circulated to the B-side, the same hardware and control method can perform the lowchieing of the data.

In addition, a shifter using rotators compatible with different sizes can similarly perform shift operations.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a sickle using rotators compatible with different sizes in a first embodiment of the present invention.

In FIG. 1, 2o is the input data, 21 is the size indicating the number of effective bits of the input data, 22 is the shift amount to be rotated, 23 is the input data copying device, 24 is the output of the input data copying device 23, and 26 is the output of the input data copying device 23. Shift amount modification device, 26
．． 27 is the output of the shift amount modifier, 28 is the rotator,
29 is the output of the rotator, 3o is the pattern generator, 3
1 is the output of the pattern generator, 32 is the logical operation device, 3
3 is an output of the logic operation device 32, 34 is a control line indicating the type of logic operation, and 36 is a control line indicating the type of shift.

In this embodiment, the bit width of input/output data and the rotator is 32 bits.

The operation of the shift configured as described above will be explained below.

When input signals 21, 22 and 36 instruct a logic shift of n(8) bits to the left for 8-bit input data, the input data copying device 23 converts the LSB
1 byte on the MSB side is copied to 1 byte on the MSB side and output from 24 (FIG. 2(a)).

The shift amount modification device 26 instructs the pattern generation device 30 and the rotator 28 to shift the amount n using 26.

The rotator outputs a value 29 which rotates the input 24 to the left by n bits, and the pattern generator outputs the value 29 from the LSB by n bits 0. A button 31 with the remaining bits set to 1 is output.

When the type of shift is a logical shift, the shift amount modification device 26 instructs the logical operation device 32 to perform the operation (pattern generator output) and (circulation device output) through 34, and the logical operation device 32 is 31 man power a
By performing 29 manual calculations, the 8-bit data is logically shifted by n bits and the result 33 is output (FIG. 2(b)).

Similarly, when the type of shift is rotate, the shift amount modification device 26 instructs the logic operation device 32 to select the rotator output through 34, and the logic operation device 32 outputs the input of 29 as it is. By doing this, you can get rotated results.

In logical shifts and arithmetic shifts, if the shift amount is larger than the data length, the shift result is all bits 0 or all bits are extended with sign bits. Compare length.

In calculation #i shift, the following specifications: 0 shift amount ≧ data length (left shift): all bits 0 0 shift amount ≦ data length (right shift); all bits sign 0 Otherwise: normal shift. In this case, the shift amount modification device performs a comparison and determines that the shift amount ≧
When the data length is specified, the logic unit is instructed to output all bits 0, and when the shift amount ≦ data length, when the sign bit of the data is 0, all bits are 0 output, and when the sign bit is 1, the output is 0. Instructs all bits to be output as 1.

The shift amount modifying device inputs the sign bit of the data through 20 input lines.

The data length and shift amount in the shift amount modification device are compared in the following manner.

Assuming that the shift amount input 22 is 8 bits and is input in two's complement representation, the shift amount is divided into three groups depending on the data length.
Divide into groups.

Figure 3(a) shows the case where the data length is 8 bits, and bit 7
~Bit 4 is HI, bit 3 is MID, and bits 2 to 0 are L. When the data length is 16 bits or 32 bits, as shown in Fig. 3 Φ), (C), HI, MID
, L.

The number of shifts≧data length is satisfied when the condition of MSB (bit 7)=Oand ((HI=all O) or (MID=1 ang L + all O)) is satisfied, and the number of shifts≦data length. MSB=1 and (HI Heor Oor MID=Oor (HI,,, O/L/1 and MID=1
and L=all 0)) is satisfied.

In this way, by changing the shift amount and the bits of interest according to the data length, 8 bits corresponding to the data length,
There is no need to have a shift amount comparing device for 16 pits and 32 bits.

Also, when performing a mask operation on the upper n bits or the lower n bits for bit field operations, 2
Data to be remasked from 0, effective data length from 21 to 22
The amount of bits to be re-masked is 35, which instructs a mask operation on the upper or lower side.

As a result, the shift amount modification device 26 sends an instruction to the pattern generation device 3o from 27 to generate a pattern that outputs the LSBg111n bits o.

The rotator 28 is instructed by the 26 to rotate 0 bits so as to output the input data without loading it.

As a result, the output 31 of the Shibata turn generator 30 has the same pattern as the normal shift, with n bits on the lower side being '0' and the remaining upper side 1, and the output 28 of the circulation device is the input data 24 as it is. The control line to the logical operation device 32 indicates @nd (rotator output) when the lower n bits are masked (pattern generator output), and the output 33 of the logical operation device 32 is input ≠ − evening. The lower n bits of the input data are masked.In addition, by instructing the upper 32-n bits to be output when the upper 32-n bits are masked, the output 33 of the logical operation unit 32 is such that the upper 32-n bits of the input data are set to 0. It will be masked.

Effects of the Invention As described above, the present invention has a structure in which the input data copying device and the fixed width rotator are provided, so that the inside of the bit is constant and has a highly regular structure, and an excellent thickness suitable for LSI can be realized.

In addition, different size shifts can be realized for input data with different numbers of effective bits without adding any hardware.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a rotator compatible with different sizes and a shift F using the same in a first embodiment of the present invention, FIG. 2 is an explanatory diagram of a shift operation in the first embodiment of the present invention, and FIG.
The figure is an explanatory diagram of a comparison of the shift amount and data size of the shift amount modification device in the first embodiment of the present invention, FIG. 4 is a configuration diagram of a conventional circulation device, and FIG. 6(a) is a conventional circulation device. The internal configuration diagram in FIG. 6 is an explanatory diagram of the circulation operation of a conventional circulation device. 1... Input data, 2... Control line indicating shift amount, 3... Rotator, 4, 5, 6,
7.8... Bit circulator, 9... Output data, 10.11... Input data, 12...
...Multiplexer, 13... Control line for instructing rotation, 14... Output of multiplexer, 16... Input data to rotator, -
516...Rotator output data, 20...
... Input data, 21 ... Input data size, 22 ... Shift amount, 23 ... Input data copying device, 24 ... Input data Output of copying device, 25...shift amount modification device, 26.
27...Schiff [output of quantity modifier, 28...
... Rotator, 29 ... Rotator output, 30 ... Pattern generator, 11 ...
- Output of pattern generator, 32...Logic operation device, 33...Output of logic operation device, 34...
...Control line indicating the type of logical operation, 36...
・Control line. Name of agent: Patent attorney Shigetaka Awano and 1 other person 1st
Figure Figure Figure 82 Noshi7 Topp Figure ID M(bn(C)) z ID Figure (λ) (b)

Claims (2)

[Claims] (1) A first input line for inputting data, a second input line for indicating the amount of shift, a third input line for indicating the effective data size of the first input line, and 2. A shift amount modification device inputting a third input line and instructing a shift; inputting the first input line and the third input line;
The data on the LSB (lower) side of the first input line is MSB.
a data copying device that copies data to the (upper) side; a rotator that receives the output of the copying device and the first control line of the shift amount modification device as inputs and performs rotation with a fixed bit width; A rotator compatible with different sizes, characterized by being equipped with 1 output line. (2) A fourth input line indicating the type of shift and a second control line output from the shift amount modification device are inputted to the rotator corresponding to different sizes and the shift amount modification device according to claim 1. , a pattern generation device that generates a specific bit pattern, the output of the rotator compatible with different sizes, the output of the pattern generation device, and the third control line of the shift amount modification device are inputted, and the pattern generation device and ,
A shifter comprising: a logic operation device that performs a logic operation with the output of the rotator corresponding to different sizes; and an output line of the logic operation device.