Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: 64 bit 90 degree rotations -- a summary from USENET

Author: Robert Hyatt

Date: 08:50:51 06/11/02

Go up one level in this thread


On June 10, 2002 at 17:21:32, Peter Fendrich wrote:

>On June 10, 2002 at 15:47:14, Dann Corbit wrote:
>
>Dann,
>why do you collect these rotating functions?
>When it comes to me I don't make any rotating during search just during the
>initial phase when the program starts.
>During search it is lookups in order to get the rotated file or diagonal.
>
>Peter
>

It is an attempt to avoid the incremental updates in Make/Unmake.  The cost
of incremental updating is not free.  Whether it is less or more expensive
than the cost of direct rotating is another issue...



>>#include <stdio.h>
>>#include <stdlib.h>
>>
>>#ifdef _MSC_VER
>>typedef unsigned __int64 uint64;
>>#else
>>typedef unsigned long long uint64;
>>#endif
>>#ifndef ASSEMBLY_GOO
>>extern double long get_time(void);
>>extern double   time_diff(double t1, double t2);
>>
>>#endif
>>static uint64   LUT[256];
>>
>>extern uint64   NOP(uint64 a);
>>extern uint64   rotate90a(uint64 a);
>>extern uint64   rotate90b(uint64 a);
>>extern uint64   rotateLa(uint64 x);
>>extern uint64   rotateLb(uint64 x);
>>extern uint64   rotateLc(uint64 x);
>>
>>extern void     dump(uint64 x);
>>extern void     fillLUT(void);
>>
>>typedef         uint64(*rotfunc) (uint64);
>>
>>typedef struct tag_rotlist {
>>    char           *description;
>>    rotfunc         r;
>>}               rotlist;
>>
>>static rotlist  rlist[] = {
>>    {"NOP", NOP},
>>    {"rotate90a", rotate90a},
>>    {"rotate90b", rotate90b},
>>    {"rotateLa", rotateLa},
>>    /* {"rotateLb", rotateLb}, */
>>    {"rotateLc", rotateLc},
>>    {0, 0}
>>};
>>
>>uint64          rotate90a(uint64 a)
>>{
>>    a = (a & 0xf0f0f0f000000000) >> 32
>>        | (a & 0x0f0f0f0f00000000) << 4
>>        | (a & 0x00000000f0f0f0f0) >> 4
>>        | (a & 0x000000000f0f0f0f) << 32;
>>    a = (a & 0xcccc0000cccc0000) >> 16
>>        | (a & 0x3333000033330000) << 2
>>        | (a & 0x0000cccc0000cccc) >> 2
>>        | (a & 0x0000333300003333) << 16;
>>    a = (a & 0xaa00aa00aa00aa00) >> 8
>>        | (a & 0x5500550055005500) << 1
>>        | (a & 0x00aa00aa00aa00aa) >> 1
>>        | (a & 0x0055005500550055) << 8;
>>    return a;
>>}
>>
>>uint64          rotate90b(uint64 a)
>>{
>>    a = (a & 0xf0f0f0f000000000) >> 32
>>        | (a << 4 & 0xf0f0f0f000000000)
>>        | (a >> 4 & 0x000000000f0f0f0f)
>>        | (a & 0x000000000f0f0f0f) << 32;
>>    a = (a & 0xcccc0000cccc0000) >> 16
>>        | (a << 2 & 0xcccc0000cccc0000)
>>        | (a >> 2 & 0x0000333300003333)
>>        | (a & 0x0000333300003333) << 16;
>>    a = (a & 0xaa00aa00aa00aa00) >> 8
>>        | (a << 1 & 0xaa00aa00aa00aa00)
>>        | (a >> 1 & 0x0055005500550055)
>>        | (a & 0x0055005500550055) << 8;
>>    return a;
>>}
>>
>>uint64          rotateLa(uint64 x)
>>{
>>    return LUT[x >> 56 & 0xff] << 7
>>         | LUT[x >> 48 & 0xff] << 6
>>         | LUT[x >> 40 & 0xff] << 5
>>         | LUT[x >> 32 & 0xff] << 4
>>         | LUT[x >> 24 & 0xff] << 3
>>         | LUT[x >> 16 & 0xff] << 2
>>         | LUT[x >> 8 & 0xff] << 1
>>         | LUT[x & 0xff];
>>}
>>
>>static const uint64 bytemask = 0xff;
>>static const uint64 longone = 1;
>>/* This one is broken
>>uint64          rotateLb(uint64 x)
>>{
>>    return LUT[x >> 56 & 0xff] & 0x80808080808080
>>    | LUT[x >> 48 & 0xff] & 0x40404040404040
>>    | LUT[x >> 40 & 0xff] & 0x20202020202020
>>    | LUT[x >> 32 & 0xff] & 0x10101010101010
>>    | LUT[x >> 24 & 0xff] & 0x08080808080808
>>    | LUT[x >> 16 & 0xff] & 0x04040404040404
>>    | LUT[x >> 8 & 0xff] & 0x02020202020202
>>    | LUT[x & 0xff] & 0x01010101010101;
>>}
>>*/
>>uint64          rotateLc(uint64 x)
>>{
>>    uint64          c7 = (x >> 56) & bytemask;
>>    uint64          c6 = (x >> 48) & bytemask;
>>    uint64          c5 = (x >> 40) & bytemask;
>>    uint64          c4 = (x >> 32) & bytemask;
>>    uint64          c3 = (x >> 24) & bytemask;
>>    uint64          c2 = (x >> 16) & bytemask;
>>    uint64          c1 = (x >> 8) & bytemask;
>>    uint64          c0 = (x) & bytemask;
>>    c7 = LUT[c7];
>>    c6 = LUT[c6];
>>    c5 = LUT[c5];
>>    c4 = LUT[c4];
>>    c3 = LUT[c3];
>>    c2 = LUT[c2];
>>    c1 = LUT[c1];
>>    c0 = LUT[c0];
>>    c5 = (c7 << 2) + c5;
>>    c4 = (c6 << 2) + c4;
>>    c3 = (c5 << 2) + c3;
>>    c2 = (c4 << 2) + c2;
>>    c1 = (c3 << 2) + c1;
>>    c0 = (c2 << 2) + c0;
>>    return (c1 << 1) + c0;
>>}
>>
>>
>>uint64          NOP(uint64 a)
>>{
>>    return a;
>>}
>>
>>#ifdef ASSEMBLY_GOO
>>uint64          getrpc(uint64 from)
>>{
>>    register uint64 result,
>>                    scratch;
>> __asm__ volatile ("rpcc %0":
>>                "=r" (result));
>>    scratch = result >> 32;
>>    result += scratch - from;
>>    result &= 0xffffffff;
>>    return result;
>>}
>>#endif
>>
>>extern uint64   NOP(uint64);
>>extern uint64   rotateL(uint64);
>>extern uint64   rotate90(uint64);
>>extern void     fillLUT(void);
>>
>>#define B1(s) (*(s)&1u)
>>#define B2(s) (B1(s)*2+B1(s+1))
>>#define B4(s) (B2(s)*4+B2(s+2))
>>#define B8(s) (B4(s)*16+B4(s+4))
>>#define B16(s) (B8(s)*256+B8(s+8))
>>#define B32(s) ((B16(s)<<16)+B16(s+16))
>>#define B64(s) (((uint64)B32(s)<<32)+B32(s+32))
>>
>>#define NUMTESTS 1
>>static uint64   test[NUMTESTS] =
>>#ifndef BROKEN_COMPILER
>>{
>>    B64("  ####  "
>>        " #  ### "
>>        "#   ####"
>>        "#   ####"
>>        "#      #"
>>        "#      #"
>>        " #    # "
>>        "  ####  ")
>>};
>>#else
>>{0};
>>#endif
>>
>>void            dump(uint64 x)
>>{
>>    int             b = 64;
>>    while (--b >= 0) {
>>        putchar(x & (longone << b) ? '#' : ' ');
>>        if ((b % 8) == 0)
>>            putchar('\n');
>>    }
>>}
>>
>>int             main(int argc, char **argv)
>>{
>>    int             r,
>>                    i;
>>#ifdef ASSEMBLY_GOO
>>    uint64          tick;
>>#else
>>    double          start,
>>                    end,
>>                    difference;
>>#endif
>>    int             index = 0;
>>    fillLUT();
>>
>>#define NUMREPS 10000000L
>>    while (rlist[index].description) {
>>
>>#ifdef ASSEMBLY_GOO
>>        tick = getrpc(0);
>>#else
>>        start = get_time();
>>#endif
>>        puts(rlist[index].description);
>>        for (r = 0; r < NUMREPS; ++r) {
>>            for (i = 0; i < NUMTESTS; ++i) {
>>                uint64          t = test[i];
>>                t = rlist[index].r(t);
>>                t = rlist[index].r(t);
>>                t = rlist[index].r(t);
>>                t = rlist[index].r(t);
>>                if (t != test[i]) {
>>                    printf("%s test %i failed, %016llx->%016llx\n",
>>rlist[index].description, i, test[i], t);
>>                    t = test[i];
>>                    dump(t);
>>                    t = rlist[index].r(t);
>>                    dump(t);
>>                    t = rlist[index].r(t);
>>                    dump(t);
>>                    t = rlist[index].r(t);
>>                    dump(t);
>>                    t = rlist[index].r(t);
>>                    dump(t);
>>                    exit(EXIT_FAILURE);
>>                }
>>            }
>>        }
>>#ifdef ASSEMBLY_GOO
>>        tick = getrpc(0);
>>        printf("%s test time %llu %g\n", rlist[index].description, tick,
>>               tick * (1.0 / (4 * NUMREPS * NUMTESTS)));
>>#else
>>        end = get_time();
>>        difference = time_diff(start, end);
>>
>>        printf("%s test time %f %g\n", rlist[index].description, difference,
>>               difference * (0.25 / (NUMREPS * NUMTESTS)));
>>#endif
>>        index++;
>>    }
>>
>>    return 0;
>>}
>>
>>void            fillLUT()
>>{
>>    int             i;
>>    for (i = 0; i < 256; ++i) {
>>        if (i & 1)
>>            LUT[i] |= longone << 56;
>>        if (i & 2)
>>            LUT[i] |= longone << 48;
>>        if (i & 4)
>>            LUT[i] |= longone << 40;
>>        if (i & 8)
>>            LUT[i] |= longone << 32;
>>        if (i & 16)
>>            LUT[i] |= longone << 24;
>>        if (i & 32)
>>            LUT[i] |= longone << 16;
>>        if (i & 64)
>>            LUT[i] |= longone << 8;
>>        if (i & 128)
>>            LUT[i] |= longone << 0;
>>    }
>>#ifdef BROKEN_COMPILER
>>    test[0] =
>>        B64("  ####  "
>>            " #  ### "
>>            "#   ####"
>>            "#   ####"
>>            "#      #"
>>            "#      #"
>>            " #    # "
>>            "  ####  ");
>>#endif
>>}
>>
>>/*
>>A couple runs produce this:
>>
>>NOP
>>NOP test time 0.321925 8.04812e-009
>>rotate90a
>>rotate90a test time 2.485504 6.21376e-008
>>rotate90b
>>rotate90b test time 2.367185 5.91796e-008
>>rotateLa
>>rotateLa test time 2.721986 6.80496e-008
>>rotateLc
>>rotateLc test time 3.308488 8.27122e-008
>>
>>NOP
>>NOP test time 0.340500 8.51249e-009
>>rotate90a
>>rotate90a test time 2.520052 6.30013e-008
>>rotate90b
>>rotate90b test time 2.463799 6.1595e-008
>>rotateLa
>>rotateLa test time 2.732862 6.83215e-008
>>rotateLc
>>rotateLc test time 3.330550 8.32637e-008
>>*/



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.