github.com/gopherd/gonum@v0.0.4/internal/asm/f32/axpyunitaryto_amd64.s (about)

     1  // Copyright ©2016 The Gonum Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build !noasm,!gccgo,!safe
     6  
     7  #include "textflag.h"
     8  
     9  // func AxpyUnitaryTo(dst []float32, alpha float32, x, y []float32)
    10  TEXT ·AxpyUnitaryTo(SB), NOSPLIT, $0
    11  	MOVQ    dst_base+0(FP), DI // DI = &dst
    12  	MOVQ    x_base+32(FP), SI  // SI = &x
    13  	MOVQ    y_base+56(FP), DX  // DX = &y
    14  	MOVQ    x_len+40(FP), BX   // BX = min( len(x), len(y), len(dst) )
    15  	CMPQ    y_len+64(FP), BX
    16  	CMOVQLE y_len+64(FP), BX
    17  	CMPQ    dst_len+8(FP), BX
    18  	CMOVQLE dst_len+8(FP), BX
    19  	CMPQ    BX, $0             // if BX == 0 { return }
    20  	JE      axpy_end
    21  	MOVSS   alpha+24(FP), X0
    22  	SHUFPS  $0, X0, X0         // X0 = { a, a, a, a, }
    23  	XORQ    AX, AX             // i = 0
    24  	MOVQ    DX, CX
    25  	ANDQ    $0xF, CX           // Align on 16-byte boundary for ADDPS
    26  	JZ      axpy_no_trim       // if CX == 0 { goto axpy_no_trim }
    27  
    28  	XORQ $0xF, CX // CX = 4 - floor ( B % 16 / 4 )
    29  	INCQ CX
    30  	SHRQ $2, CX
    31  
    32  axpy_align: // Trim first value(s) in unaligned buffer  do {
    33  	MOVSS (SI)(AX*4), X2 // X2 = x[i]
    34  	MULSS X0, X2         // X2 *= a
    35  	ADDSS (DX)(AX*4), X2 // X2 += y[i]
    36  	MOVSS X2, (DI)(AX*4) // y[i] = X2
    37  	INCQ  AX             // i++
    38  	DECQ  BX
    39  	JZ    axpy_end       // if --BX == 0 { return }
    40  	LOOP  axpy_align     // } while --CX > 0
    41  
    42  axpy_no_trim:
    43  	MOVUPS X0, X1           // Copy X0 to X1 for pipelining
    44  	MOVQ   BX, CX
    45  	ANDQ   $0xF, BX         // BX = len % 16
    46  	SHRQ   $4, CX           // CX = floor( len / 16 )
    47  	JZ     axpy_tail4_start // if CX == 0 { return }
    48  
    49  axpy_loop: // Loop unrolled 16x  do {
    50  	MOVUPS (SI)(AX*4), X2   // X2 = x[i:i+4]
    51  	MOVUPS 16(SI)(AX*4), X3
    52  	MOVUPS 32(SI)(AX*4), X4
    53  	MOVUPS 48(SI)(AX*4), X5
    54  	MULPS  X0, X2           // X2 *= a
    55  	MULPS  X1, X3
    56  	MULPS  X0, X4
    57  	MULPS  X1, X5
    58  	ADDPS  (DX)(AX*4), X2   // X2 += y[i:i+4]
    59  	ADDPS  16(DX)(AX*4), X3
    60  	ADDPS  32(DX)(AX*4), X4
    61  	ADDPS  48(DX)(AX*4), X5
    62  	MOVUPS X2, (DI)(AX*4)   // dst[i:i+4] = X2
    63  	MOVUPS X3, 16(DI)(AX*4)
    64  	MOVUPS X4, 32(DI)(AX*4)
    65  	MOVUPS X5, 48(DI)(AX*4)
    66  	ADDQ   $16, AX          // i += 16
    67  	LOOP   axpy_loop        // while (--CX) > 0
    68  	CMPQ   BX, $0           // if BX == 0 { return }
    69  	JE     axpy_end
    70  
    71  axpy_tail4_start: // Reset loop counter for 4-wide tail loop
    72  	MOVQ BX, CX          // CX = floor( BX / 4 )
    73  	SHRQ $2, CX
    74  	JZ   axpy_tail_start // if CX == 0 { goto axpy_tail_start }
    75  
    76  axpy_tail4: // Loop unrolled 4x  do {
    77  	MOVUPS (SI)(AX*4), X2 // X2 = x[i]
    78  	MULPS  X0, X2         // X2 *= a
    79  	ADDPS  (DX)(AX*4), X2 // X2 += y[i]
    80  	MOVUPS X2, (DI)(AX*4) // y[i] = X2
    81  	ADDQ   $4, AX         // i += 4
    82  	LOOP   axpy_tail4     // } while --CX > 0
    83  
    84  axpy_tail_start: // Reset loop counter for 1-wide tail loop
    85  	MOVQ BX, CX   // CX = BX % 4
    86  	ANDQ $3, CX
    87  	JZ   axpy_end // if CX == 0 { return }
    88  
    89  axpy_tail:
    90  	MOVSS (SI)(AX*4), X1 // X1 = x[i]
    91  	MULSS X0, X1         // X1 *= a
    92  	ADDSS (DX)(AX*4), X1 // X1 += y[i]
    93  	MOVSS X1, (DI)(AX*4) // y[i] = X1
    94  	INCQ  AX             // i++
    95  	LOOP  axpy_tail      // } while --CX > 0
    96  
    97  axpy_end:
    98  	RET