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// compile
// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This tickles (a version of) the PPC64 back end to
// emit a BVS instruction.
package foo
type Flag int
const (
Identity Flag = iota - 2 // H is the identity matrix; no rotation is needed.
Rescaling // H specifies rescaling.
)
type DrotmParams struct {
Flag
}
func Drotmg(d1, d2, x1, y1 float64) (p DrotmParams, rd1, rd2, rx1 float64) {
const (
gam = 4.0
gamsq = 16.0
rgamsq = 5e-8
)
if d1 < 0 {
p.Flag = Rescaling
return
}
for rd1 <= rgamsq || rd1 >= gamsq {
if rd1 <= rgamsq {
rd1 *= gam * gam
rx1 /= gam
} else {
rd1 /= gam * gam
rx1 *= gam
}
}
return
}
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