1 // Copyright ©2017 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.
5 //+build !noasm,!appengine
17 #define MOVDDUP_ALPHA LONG $0x44120FF2; WORD $0x0824 // MOVDDUP 8(SP), X0
19 // func DscalUnitary(alpha float64, x []complex128)
20 TEXT ·DscalUnitary(SB), NOSPLIT, $0
21 MOVQ x_base+8(FP), SRC // SRC = &x
22 MOVQ x_len+16(FP), LEN // LEN = len(x)
23 CMPQ LEN, $0 // if LEN == 0 { return }
26 MOVDDUP_ALPHA // ALPHA = alpha
27 XORQ IDX, IDX // IDX = 0
28 MOVUPS ALPHA, ALPHA_2 // Copy ALPHA to ALPHA_2 for pipelining
29 MOVQ LEN, TAIL // TAIL = LEN
30 SHRQ $2, LEN // LEN = floor( n / 4 )
31 JZ dscal_tail // if LEN == 0 { goto dscal_tail }
34 MOVUPS (SRC)(IDX*8), X2 // X_i = x[i]
35 MOVUPS 16(SRC)(IDX*8), X3
36 MOVUPS 32(SRC)(IDX*8), X4
37 MOVUPS 48(SRC)(IDX*8), X5
39 MULPD ALPHA, X2 // X_i *= ALPHA
44 MOVUPS X2, (DST)(IDX*8) // x[i] = X_i
45 MOVUPS X3, 16(DST)(IDX*8)
46 MOVUPS X4, 32(DST)(IDX*8)
47 MOVUPS X5, 48(DST)(IDX*8)
49 ADDQ $8, IDX // IDX += 8
51 JNZ dscal_loop // } while --LEN > 0
54 ANDQ $3, TAIL // TAIL = TAIL % 4
55 JZ dscal_end // if TAIL == 0 { return }
57 dscal_tail_loop: // do {
58 MOVUPS (SRC)(IDX*8), X2 // X_i = x[i]
59 MULPD ALPHA, X2 // X_i *= ALPHA
60 MOVUPS X2, (DST)(IDX*8) // x[i] = X_i
61 ADDQ $2, IDX // IDX += 2
63 JNZ dscal_tail_loop // } while --TAIL > 0