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shifting arrays

hi,

i'm using uVision3.33 , uC-80c31x2.
my question is:
I'v initilize buffer array which is been loaded with 24 Byte each interval time.
now i want to shift the all array right/left by 1 bit.
maybe an example will clarify bettet:

unsigned char array_1[24];
unsigned char array_1[24] = {
0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x20,0x21,0x22,0x23,0x24};

the array's values in the example are just for example.
probably the operand '>>' must be use.
the result i wish for is:
(shifting all the array right only one time)

unsigned char array_1[24] = {
0x00,0x81,0x01,0x82,0x02,.....,0x92};

thanks in advance.

Parents

0 ImPer Westermark over 17 years ago in reply to Andy Neil

#include <stdio.h>

int main() {
    unsigned char array_1[24] = {
        0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,
        0x09,0x10,0x11,0x12,0x13,0x14,0x15,0x16,
        0x17,0x18,0x19,0x20,0x21,0x22,0x23,0x24};
    int i;

    for (i = 0; i < sizeof(array_1); i++) {
        printf("%02x ",array_1[i]);
    }
    printf("\n");

    // Shift all data right one bit, with carry from lower index.
    for (i = 23; i >= 1; --i) {
        array_1[i] = (array_1[i]>>1) | ((array_1[i-1] << 7) & 0x80);
    }
    array_1[0] >>= 1; // possibly take care of rotate from last entry too.
    for (i = 0; i < sizeof(array_1); i++) {
        printf("%02x ",array_1[i]);
    }
    printf("\n");

    // Shift all data left one bit, with carry from higher index.
    for (i = 0; i < 23; i++) {
        array_1[i] = (array_1[i] << 1) | ((array_1[i+1] >> 7) & 0x01);
    }
    array_1[23] <<= 1; // possibly take care of rotate from first entry too.
    for (i = 0; i < sizeof(array_1); i++) {
        printf("%02x ",array_1[i]);
    }
    printf("\n");
    return 0;
}

Gives result:

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
00 81 01 82 02 83 03 84 04 88 08 89 09 8a 0a 8b 0b 8c 0c 90 10 91 11 92
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Reply

0 ImPer Westermark over 17 years ago in reply to Andy Neil

#include <stdio.h>

int main() {
    unsigned char array_1[24] = {
        0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,
        0x09,0x10,0x11,0x12,0x13,0x14,0x15,0x16,
        0x17,0x18,0x19,0x20,0x21,0x22,0x23,0x24};
    int i;

    for (i = 0; i < sizeof(array_1); i++) {
        printf("%02x ",array_1[i]);
    }
    printf("\n");

    // Shift all data right one bit, with carry from lower index.
    for (i = 23; i >= 1; --i) {
        array_1[i] = (array_1[i]>>1) | ((array_1[i-1] << 7) & 0x80);
    }
    array_1[0] >>= 1; // possibly take care of rotate from last entry too.
    for (i = 0; i < sizeof(array_1); i++) {
        printf("%02x ",array_1[i]);
    }
    printf("\n");

    // Shift all data left one bit, with carry from higher index.
    for (i = 0; i < 23; i++) {
        array_1[i] = (array_1[i] << 1) | ((array_1[i+1] >> 7) & 0x01);
    }
    array_1[23] <<= 1; // possibly take care of rotate from first entry too.
    for (i = 0; i < sizeof(array_1); i++) {
        printf("%02x ",array_1[i]);
    }
    printf("\n");
    return 0;
}

Gives result:

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
00 81 01 82 02 83 03 84 04 88 08 89 09 8a 0a 8b 0b 8c 0c 90 10 91 11 92
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Children

No data