OpenBLAS/kernel/power/izamin.c

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#include "common.h"
#include <math.h>
 
#define ABS fabs 
#define CABS1(x,i)    ABS(x[i])+ABS(x[i+1])

 
/**
 * Find  minimum index 
 * Warning: requirements n>0  and n % 16 == 0
 * @param n     
 * @param x     pointer to the vector
 * @param minf  (out) minimum absolute value .( only for output )
 * @return minimum index 
 */
static BLASLONG ziamin_kernel_16_TUNED(BLASLONG n, FLOAT *x, FLOAT *minf) { 

    BLASLONG index;
    register __vector long long start = {1,0};
    register __vector long long temp_add_index = {2, 2}; 
   __asm__(

            "lxvd2x  44,      0,%[ptr_tmp] \n\t"
            "lxvd2x  45, %[i16],%[ptr_tmp] \n\t"
            "lxvd2x  46, %[i32],%[ptr_tmp] \n\t"
            "lxvd2x  47, %[i48],%[ptr_tmp] \n\t"
            "lxvd2x  48, %[i64],%[ptr_tmp] \n\t"
            "lxvd2x  49, %[i80],%[ptr_tmp] \n\t"  
            "lxvd2x  50, %[i96],%[ptr_tmp] \n\t"
            "lxvd2x  51,%[i112],%[ptr_tmp] \n\t"      

            "xxlor  40,%x[start],%x[start]  \n\t" //{ 1,0} vs40 | v8 
            "vaddudm  9,8,%[adder]   \n\t" //{3,2} vs41 
            "xxlxor  37,37 ,37       \n\t" //v5 v37 index_count
            "vaddudm  10,9,%[adder]  \n\t" //{5,4} vs42
            "xxlxor  38 ,38 ,38      \n\t"  // v6 | vs38 vec_min_index
            "vaddudm  11,10,%[adder] \n\t" //{7,6} vs43
            "lxvdsx  39,0,%[ptr_minf] \n\t" //   vs39 vec_min_value
            "vaddudm 4,11,  %[adder] \n\t" // {9,8} -{8;8} vs36 | v4
            "xxspltd   36,36,0       \n\t"



            "xvabsdp  44, 44 \n\t"
            "xvabsdp  45, 45 \n\t" 
            "xvabsdp  46, 46 \n\t"
            "xvabsdp  47, 47 \n\t"   
            "xvabsdp  48, 48 \n\t"
            "xvabsdp  49, 49 \n\t"   
            "xvabsdp  50, 50 \n\t"
            "xvabsdp  51, 51 \n\t"

            //jump first half forward 
            "b 2f  \n\t"

            ".p2align   5            \n\t"
            "1: \n\t"

 
            "xxmrghd    0,44,45  \n\t"
            "xxmrgld    1,44,45  \n\t"
            "xxmrghd    2,46,47  \n\t"
            "xxmrgld    3,46,47  \n\t"
            "xxmrghd    4,48,49  \n\t"
            "xxmrgld    5,48,49  \n\t"
            "xxmrghd    44,50,51  \n\t"
            "xxmrgld    45,50,51  \n\t"

            "xvadddp    46,  0,1 \n\t"
            "xvadddp    47,  2,3 \n\t" 
            "xvadddp    48,  4,5 \n\t"
            "xvadddp    49,  44,45 \n\t"



            "xvcmpgtdp  50,46,47  \n\t "
            "xvcmpgtdp  51,48,49  \n\t "

            "addi     %[ptr_tmp] ,%[ptr_tmp] , 128 \n\t"   

            "xxsel    32,40,41,50 \n\t"
            "xxsel     0,46,47,50 \n\t" 
            "xxsel    33,42,43,51 \n\t"
            "xxsel     1,48,49,51 \n\t"  

            "lxvd2x  44,      0,%[ptr_tmp] \n\t"
            "lxvd2x  45, %[i16],%[ptr_tmp] \n\t"

            "xvcmpgtdp  2,0,1  \n\t "             
            "lxvd2x  46, %[i32],%[ptr_tmp] \n\t"
            "lxvd2x  47, %[i48],%[ptr_tmp] \n\t"


            "xxsel    32,32,33,2 \n\t" 
            "xxsel    3,0,1,2 \n\t" 
     
            "vaddudm   0,0,5       \n\t"

             //cmp with previous

            "xvcmpgtdp 4,39,3     \n\t "  
            "vaddudm   5,5,4      \n\t"     

            "lxvd2x  48, %[i64],%[ptr_tmp] \n\t"
            "lxvd2x  49, %[i80],%[ptr_tmp] \n\t"  
            "lxvd2x  50, %[i96],%[ptr_tmp] \n\t"
            "lxvd2x  51,%[i112],%[ptr_tmp] \n\t"        
             //select with previous 
            "xxsel     38,38,32,4 \n\t" 
            "xxsel    39,39,3,4    \n\t" 




            "xvabsdp  44, 44 \n\t"
            "xvabsdp  45, 45 \n\t" 
            "xvabsdp  46, 46 \n\t"
            "xvabsdp  47, 47 \n\t"   
            "xvabsdp  48, 48 \n\t"
            "xvabsdp  49, 49 \n\t"   
            "xvabsdp  50, 50 \n\t"
            "xvabsdp  51, 51 \n\t"


//>>///////////////////////////////  half start
            "2:   \n\t"
            "xxmrghd    0,44,45  \n\t"
            "xxmrgld    1,44,45  \n\t"
            "xxmrghd    2,46,47  \n\t"
            "xxmrgld    3,46,47  \n\t"
            "xxmrghd    4,48,49  \n\t"
            "xxmrgld    5,48,49  \n\t"
            "xxmrghd    44,50,51  \n\t"
            "xxmrgld    45,50,51  \n\t"

            "xvadddp    46,  0,1 \n\t"
            "xvadddp    47,  2,3 \n\t" 
            "xvadddp    48,  4,5 \n\t"
            "xvadddp    49,  44,45 \n\t"

            "xvcmpgtdp  50,46,47  \n\t "
            "xvcmpgtdp  51,48,49  \n\t "

            "addi     %[ptr_tmp] ,%[ptr_tmp] , 128 \n\t"   

            "xxsel    32,40,41,50 \n\t"
            "xxsel     0,46,47,50 \n\t" 
            "xxsel    33,42,43,51 \n\t"
            "xxsel     1,48,49,51 \n\t"  

            "lxvd2x  44,      0,%[ptr_tmp] \n\t"
            "lxvd2x  45, %[i16],%[ptr_tmp] \n\t"

            "xvcmpgtdp  2,0,1  \n\t "             
            "lxvd2x  46, %[i32],%[ptr_tmp] \n\t"
            "lxvd2x  47, %[i48],%[ptr_tmp] \n\t"


            "xxsel    32,32,33,2 \n\t" 
            "xxsel    3,0,1,2 \n\t" 
     
            "vaddudm   0,0,5       \n\t"

             //cmp with previous

            "xvcmpgtdp 4,39,3     \n\t "  
            "vaddudm   5,5,4      \n\t"     

            "lxvd2x  48, %[i64],%[ptr_tmp] \n\t"
            "lxvd2x  49, %[i80],%[ptr_tmp] \n\t"  
            "lxvd2x  50, %[i96],%[ptr_tmp] \n\t"
            "lxvd2x  51,%[i112],%[ptr_tmp] \n\t"        
             //select with previous 
            "xxsel     38,38,32,4 \n\t" 
            "xxsel    39,39,3,4    \n\t" 
 

            "xvabsdp  44, 44 \n\t"
            "xvabsdp  45, 45 \n\t" 
            "xvabsdp  46, 46 \n\t"
            "xvabsdp  47, 47 \n\t"   
            "xvabsdp  48, 48 \n\t"
            "xvabsdp  49, 49 \n\t"   
            "xvabsdp  50, 50 \n\t"
            "xvabsdp  51, 51 \n\t"


            //decrement n
            "addic.    %[n], %[n], -16 \n\t"
            //Loop back if >0
            "bgt+ 1b  \n\t"


            "xxmrghd    0,44,45  \n\t"
            "xxmrgld    1,44,45  \n\t"
            "xxmrghd    2,46,47  \n\t"
            "xxmrgld    3,46,47  \n\t"
            "xxmrghd    4,48,49  \n\t"
            "xxmrgld    5,48,49  \n\t"
            "xxmrghd    44,50,51  \n\t"
            "xxmrgld    45,50,51  \n\t"

            "xvadddp    46,  0,1 \n\t"
            "xvadddp    47,  2,3 \n\t" 
            "xvadddp    48,  4,5 \n\t"
            "xvadddp    49,  44,45 \n\t"



            "xvcmpgtdp  50,46,47  \n\t "
            "xvcmpgtdp  51,48,49  \n\t "

            "xxsel    32,40,41,50 \n\t"
            "xxsel     0,46,47,50 \n\t" 
            "xxsel    33,42,43,51 \n\t"
            "xxsel     1,48,49,51 \n\t"  

            "xvcmpgtdp  2,0,1  \n\t " 
            "xxsel    32,32,33,2 \n\t" 
            "xxsel    3,0,1,2 \n\t" 
     
            "vaddudm   0,0,5       \n\t"

            "addi     %[ptr_tmp] ,%[ptr_tmp] , 128 \n\t"            
             //cmp with previous

            "xvcmpgtdp 4,39,3     \n\t "  
            "vaddudm   5,5,4      \n\t"     
            "xxsel     38,38,32,4 \n\t" 
            "xxsel    39,39,3,4    \n\t" 


            ///////extract min value and min index from vector

            "xxspltd   32,38,1     \n\t"
            "xxspltd   40,39,1     \n\t"
            "xvcmpeqdp.  2, 40,39  \n\t"
    
            //cr6 0 bit set if all true, cr6=4*6+bit_ind=24,0011at CR(BI)==1, at=10 hint that it occurs rarely
             //0b001110=14
            "bc 14,24, 3f  \n\t" 
            "xvcmpgtdp  4,39, 40  \n\t"
            "xxsel    0,39,40,4           \n\t"
            "xxsel    1,38,32,4  \n\t"
            "stxsdx    0,0,%[ptr_minf]     \n\t" 
            "b 4f    \n\t"

            "3:      \n\t" 
                //if elements value are equal then choose minimum index
            "xxspltd  0,40,0          \n\t"
            "vminud   0,0,6    \n\t"  //vs32 vs38
            "xxlor 1,32,32     \n\t"
            "stxsdx   0,0,%[ptr_minf]  \n\t"
          

            "4:      \n\t"
            "mfvsrd   %[index],1 \n\t"

            : [minf] "=m"(*minf),[ptr_tmp] "+&b"(x),[index] "=r"(index), [n] "+&r"(n)
            : [mem] "m"(*(const double (*)[2*n])x), [ptr_x] "b"(x), [ptr_minf] "b"(minf) ,
            [i16] "b"(16), [i32] "b"(32), [i48] "b"(48),
            [i64] "b"(64), [i80] "b"(80), [i96] "b"(96), [i112] "b"(112),
            [start] "v"(start),  [adder] "v"(temp_add_index)
            : "cc", "vs0", "vs1","vs2","vs3", "vs4","vs5","vs32", "vs33", "vs34", "vs35", "vs36",
            "vs37", "vs38", "vs39", "vs40", "vs41", "vs42", "vs43", "vs44", "vs45", "vs46", "vs47", "vs48", "vs49", "vs50", "vs51"
            );
 
    return index; 
}

 

 
 

BLASLONG CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x)
{
    BLASLONG i=0;
    BLASLONG ix=0;
    FLOAT minf;
    BLASLONG min=0;
    BLASLONG inc_x2;

    if (n <= 0 || inc_x <= 0) return(min);
    

    if (inc_x == 1) {
        minf = CABS1(x,0); //index will not be incremented
        BLASLONG n1 = n & -16;
        if (n1 > 0) {

            min = ziamin_kernel_16_TUNED(n1, x, &minf);
            i = n1;
            ix = n1 << 1;
        }
      

        while(i < n)
        {
            if( CABS1(x,ix) < minf )
            {
                min = i;
                minf = CABS1(x,ix);
            }
            ix += 2;
            i++;
        }
        return (min + 1);

    } else {
 
        inc_x2 = 2 * inc_x;

        minf = CABS1(x,0);
        ix += inc_x2;
        i++;

        while(i < n)
        {
            if( CABS1(x,ix) < minf )
            {
                min = i;
                minf = CABS1(x,ix);
            }
            ix += inc_x2;
            i++;
        }
        return (min + 1);
    }
 
}