OpenBLAS/kernel/loongarch64/snrm2_lsx.S

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#define ASSEMBLER

#include "common.h"

#define N      $r4
#define X      $r5
#define INCX   $r6
#define I      $r17
#define TEMP   $r18
#define t1     $r12
#define t2     $r13
#define t3     $r14
#define t4     $r15
#define VX0    $vr15
#define VX1    $vr16
#define VX2    $vr17
#define VX3    $vr18
#define VX4    $vr21
#define VX5    $vr22
/* Don't change following FR unless you know the effects. */
#define res1   $vr19
#define res2   $vr20
#define RCP    $f2
#define VALPHA $vr3

// The optimization for snrm2 cannot simply involve
// extending the data type from float to double and
// then summing the squares of the data. LAPACK tests
// have shown that this approach can still lead to data overflow.
// Instead, we need to find the maximum absolute value in the entire
// array and divide each data element by this maximum value before
// performing the calculation. This approach can avoid overflow (and does not require extending the data type).

   PROLOGUE

#ifdef F_INTERFACE
   LDINT   N,     0(N)
   LDINT   INCX,  0(INCX)
#endif
   bge $r0,    N, .L999
   beq $r0, INCX, .L999

   addi.d  $sp,     $sp,     -32
   st.d    $ra,     $sp,     0
   st.d    N,       $sp,     8
   st.d    X,       $sp,     16
   st.d    INCX,    $sp,     24
#ifdef DYNAMIC_ARCH
   bl samax_k_LA264
#else
   bl samax_k
#endif
   ld.d    $ra,     $sp,     0
   ld.d    N,       $sp,     8
   ld.d    X,       $sp,     16
   ld.d    INCX,    $sp,     24
   addi.d  $sp,     $sp,     32

   frecip.s RCP, $f0
   vreplvei.w   VALPHA, $vr2, 0
   vxor.v res1, res1, res1
   vxor.v res2, res2, res2
   fcmp.ceq.s  $fcc0, $f0,  $f19
   bcnez  $fcc0, .L999
   li.d  TEMP, SIZE
   slli.d INCX, INCX, BASE_SHIFT
   srai.d I, N, 3
   bne INCX, TEMP, .L20
   bge  $r0,    I, .L997
   .align 3

.L10:
   vld  VX0, X, 0
   vld  VX5, X, 4 * SIZE
   addi.d I, I, -1
   addi.d X, X, 8 * SIZE

   vfmul.s  VX0,  VX0,  VALPHA
   vfmul.s  VX5,  VX5,  VALPHA

   vfmadd.s res1, VX0, VX0, res1
   vfmadd.s res2, VX5, VX5, res2
   blt $r0, I, .L10
   b .L996
   .align 3

.L20:
   bge $r0, I, .L997
   .align 3

.L21:
   ld.w t1, X, 0
   add.d X, X, INCX
   ld.w t2, X, 0
   add.d X, X, INCX
   ld.w t3, X, 0
   add.d X, X, INCX
   ld.w t4, X, 0
   add.d X, X, INCX
   vinsgr2vr.w VX0, t1, 0
   vinsgr2vr.w VX0, t2, 1
   vinsgr2vr.w VX0, t3, 2
   vinsgr2vr.w VX0, t4, 3
   vfmul.s  VX0,  VX0,  VALPHA
   vfmadd.s res1, VX0, VX0, res1

   ld.w t1, X, 0
   add.d X, X, INCX
   ld.w t2, X, 0
   add.d X, X, INCX
   ld.w t3, X, 0
   add.d X, X, INCX
   ld.w t4, X, 0
   add.d X, X, INCX
   vinsgr2vr.w VX0, t1, 0
   vinsgr2vr.w VX0, t2, 1
   vinsgr2vr.w VX0, t3, 2
   vinsgr2vr.w VX0, t4, 3
   vfmul.s  VX0,  VX0,  VALPHA
   vfmadd.s res2, VX0, VX0, res2
   addi.d  I, I, -1
   blt $r0, I, .L21
   .align 3

.L996:
   vfadd.s res1, res1, res2
   vreplvei.w VX1, res1, 1
   vreplvei.w VX2, res1, 2
   vreplvei.w VX3, res1, 3
   vfadd.s res1, VX1, res1
   vfadd.s res1, VX2, res1
   vfadd.s res1, VX3, res1
   .align 3

.L997:
   andi I, N, 7
   bge $r0, I, .L999
   .align 3

.L998:
   fld.s $f15, X, 0
   addi.d I, I, -1
   fmul.s  $f15, $f15, RCP
   fmadd.s $f19, $f15, $f15, $f19
   add.d X, X, INCX
   blt $r0, I, .L998
   .align 3

.L999:
   fsqrt.s $f19, $f19
   fmul.s  $f0, $f19, $f0
   move $r4, $r17
   jirl $r0, $r1, 0x0
   .align 3

   EPILOGUE