// Copyright 2009 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.

package gc

import "cmd/internal/obj"

func CASE(a int, b int) int {
	return a<<16 | b
}

func overlap_cplx(f *Node, t *Node) bool {
	// check whether f and t could be overlapping stack references.
	// not exact, because it's hard to check for the stack register
	// in portable code.  close enough: worst case we will allocate
	// an extra temporary and the registerizer will clean it up.
	return f.Op == OINDREG && t.Op == OINDREG && f.Xoffset+f.Type.Width >= t.Xoffset && t.Xoffset+t.Type.Width >= f.Xoffset
}

func Complexbool(op int, nl *Node, nr *Node, true_ bool, likely int, to *obj.Prog) {
	var tnl Node
	var tnr Node
	var n1 Node
	var n2 Node
	var n3 Node
	var n4 Node
	var na Node
	var nb Node
	var nc Node

	// make both sides addable in ullman order
	if nr != nil {
		if nl.Ullman > nr.Ullman && nl.Addable == 0 {
			Tempname(&tnl, nl.Type)
			Thearch.Cgen(nl, &tnl)
			nl = &tnl
		}

		if nr.Addable == 0 {
			Tempname(&tnr, nr.Type)
			Thearch.Cgen(nr, &tnr)
			nr = &tnr
		}
	}

	if nl.Addable == 0 {
		Tempname(&tnl, nl.Type)
		Thearch.Cgen(nl, &tnl)
		nl = &tnl
	}

	// build tree
	// real(l) == real(r) && imag(l) == imag(r)

	subnode(&n1, &n2, nl)

	subnode(&n3, &n4, nr)

	na = Node{}
	na.Op = OANDAND
	na.Left = &nb
	na.Right = &nc
	na.Type = Types[TBOOL]

	nb = Node{}
	nb.Op = OEQ
	nb.Left = &n1
	nb.Right = &n3
	nb.Type = Types[TBOOL]

	nc = Node{}
	nc.Op = OEQ
	nc.Left = &n2
	nc.Right = &n4
	nc.Type = Types[TBOOL]

	if op == ONE {
		true_ = !true_
	}

	Thearch.Bgen(&na, true_, likely, to)
}

// break addable nc-complex into nr-real and ni-imaginary
func subnode(nr *Node, ni *Node, nc *Node) {
	var tc int
	var t *Type

	if nc.Addable == 0 {
		Fatal("subnode not addable")
	}

	tc = Simsimtype(nc.Type)
	tc = cplxsubtype(tc)
	t = Types[tc]

	if nc.Op == OLITERAL {
		nodfconst(nr, t, &nc.Val.U.Cval.Real)
		nodfconst(ni, t, &nc.Val.U.Cval.Imag)
		return
	}

	*nr = *nc
	nr.Type = t

	*ni = *nc
	ni.Type = t
	ni.Xoffset += t.Width
}

// generate code res = -nl
func minus(nl *Node, res *Node) {
	var ra Node

	ra = Node{}
	ra.Op = OMINUS
	ra.Left = nl
	ra.Type = nl.Type
	Thearch.Cgen(&ra, res)
}

// build and execute tree
//	real(res) = -real(nl)
//	imag(res) = -imag(nl)
func complexminus(nl *Node, res *Node) {
	var n1 Node
	var n2 Node
	var n5 Node
	var n6 Node

	subnode(&n1, &n2, nl)
	subnode(&n5, &n6, res)

	minus(&n1, &n5)
	minus(&n2, &n6)
}

// build and execute tree
//	real(res) = real(nl) op real(nr)
//	imag(res) = imag(nl) op imag(nr)
func complexadd(op int, nl *Node, nr *Node, res *Node) {
	var n1 Node
	var n2 Node
	var n3 Node
	var n4 Node
	var n5 Node
	var n6 Node
	var ra Node

	subnode(&n1, &n2, nl)
	subnode(&n3, &n4, nr)
	subnode(&n5, &n6, res)

	ra = Node{}
	ra.Op = uint8(op)
	ra.Left = &n1
	ra.Right = &n3
	ra.Type = n1.Type
	Thearch.Cgen(&ra, &n5)

	ra = Node{}
	ra.Op = uint8(op)
	ra.Left = &n2
	ra.Right = &n4
	ra.Type = n2.Type
	Thearch.Cgen(&ra, &n6)
}

// build and execute tree
//	tmp       = real(nl)*real(nr) - imag(nl)*imag(nr)
//	imag(res) = real(nl)*imag(nr) + imag(nl)*real(nr)
//	real(res) = tmp
func complexmul(nl *Node, nr *Node, res *Node) {
	var n1 Node
	var n2 Node
	var n3 Node
	var n4 Node
	var n5 Node
	var n6 Node
	var rm1 Node
	var rm2 Node
	var ra Node
	var tmp Node

	subnode(&n1, &n2, nl)
	subnode(&n3, &n4, nr)
	subnode(&n5, &n6, res)
	Tempname(&tmp, n5.Type)

	// real part -> tmp
	rm1 = Node{}

	rm1.Op = OMUL
	rm1.Left = &n1
	rm1.Right = &n3
	rm1.Type = n1.Type

	rm2 = Node{}
	rm2.Op = OMUL
	rm2.Left = &n2
	rm2.Right = &n4
	rm2.Type = n2.Type

	ra = Node{}
	ra.Op = OSUB
	ra.Left = &rm1
	ra.Right = &rm2
	ra.Type = rm1.Type
	Thearch.Cgen(&ra, &tmp)

	// imag part
	rm1 = Node{}

	rm1.Op = OMUL
	rm1.Left = &n1
	rm1.Right = &n4
	rm1.Type = n1.Type

	rm2 = Node{}
	rm2.Op = OMUL
	rm2.Left = &n2
	rm2.Right = &n3
	rm2.Type = n2.Type

	ra = Node{}
	ra.Op = OADD
	ra.Left = &rm1
	ra.Right = &rm2
	ra.Type = rm1.Type
	Thearch.Cgen(&ra, &n6)

	// tmp ->real part
	Thearch.Cgen(&tmp, &n5)
}

func nodfconst(n *Node, t *Type, fval *Mpflt) {
	*n = Node{}
	n.Op = OLITERAL
	n.Addable = 1
	ullmancalc(n)
	n.Val.U.Fval = fval
	n.Val.Ctype = CTFLT
	n.Type = t

	if Isfloat[t.Etype] == 0 {
		Fatal("nodfconst: bad type %v", Tconv(t, 0))
	}
}

/*
 * cplx.c
 */
func Complexop(n *Node, res *Node) bool {
	if n != nil && n.Type != nil {
		if Iscomplex[n.Type.Etype] != 0 {
			goto maybe
		}
	}

	if res != nil && res.Type != nil {
		if Iscomplex[res.Type.Etype] != 0 {
			goto maybe
		}
	}

	if n.Op == OREAL || n.Op == OIMAG {
		goto yes
	}

	goto no

maybe:
	switch n.Op {
	case OCONV, // implemented ops
		OADD,
		OSUB,
		OMUL,
		OMINUS,
		OCOMPLEX,
		OREAL,
		OIMAG:
		goto yes

	case ODOT,
		ODOTPTR,
		OINDEX,
		OIND,
		ONAME:
		goto yes
	}

	//dump("\ncomplex-no", n);
no:
	return false

	//dump("\ncomplex-yes", n);
yes:
	return true
}

func Complexmove(f *Node, t *Node) {
	var ft int
	var tt int
	var n1 Node
	var n2 Node
	var n3 Node
	var n4 Node
	var tmp Node

	if Debug['g'] != 0 {
		Dump("\ncomplexmove-f", f)
		Dump("complexmove-t", t)
	}

	if t.Addable == 0 {
		Fatal("complexmove: to not addable")
	}

	ft = Simsimtype(f.Type)
	tt = Simsimtype(t.Type)
	switch uint32(ft)<<16 | uint32(tt) {
	default:
		Fatal("complexmove: unknown conversion: %v -> %v\n", Tconv(f.Type, 0), Tconv(t.Type, 0))

		// complex to complex move/convert.
	// make f addable.
	// also use temporary if possible stack overlap.
	case TCOMPLEX64<<16 | TCOMPLEX64,
		TCOMPLEX64<<16 | TCOMPLEX128,
		TCOMPLEX128<<16 | TCOMPLEX64,
		TCOMPLEX128<<16 | TCOMPLEX128:
		if f.Addable == 0 || overlap_cplx(f, t) {
			Tempname(&tmp, f.Type)
			Complexmove(f, &tmp)
			f = &tmp
		}

		subnode(&n1, &n2, f)
		subnode(&n3, &n4, t)

		Thearch.Cgen(&n1, &n3)
		Thearch.Cgen(&n2, &n4)
	}
}

func Complexgen(n *Node, res *Node) {
	var nl *Node
	var nr *Node
	var tnl Node
	var tnr Node
	var n1 Node
	var n2 Node
	var tmp Node
	var tl int
	var tr int

	if Debug['g'] != 0 {
		Dump("\ncomplexgen-n", n)
		Dump("complexgen-res", res)
	}

	for n.Op == OCONVNOP {
		n = n.Left
	}

	// pick off float/complex opcodes
	switch n.Op {
	case OCOMPLEX:
		if res.Addable != 0 {
			subnode(&n1, &n2, res)
			Tempname(&tmp, n1.Type)
			Thearch.Cgen(n.Left, &tmp)
			Thearch.Cgen(n.Right, &n2)
			Thearch.Cgen(&tmp, &n1)
			return
		}

	case OREAL,
		OIMAG:
		nl = n.Left
		if nl.Addable == 0 {
			Tempname(&tmp, nl.Type)
			Complexgen(nl, &tmp)
			nl = &tmp
		}

		subnode(&n1, &n2, nl)
		if n.Op == OREAL {
			Thearch.Cgen(&n1, res)
			return
		}

		Thearch.Cgen(&n2, res)
		return
	}

	// perform conversion from n to res
	tl = Simsimtype(res.Type)

	tl = cplxsubtype(tl)
	tr = Simsimtype(n.Type)
	tr = cplxsubtype(tr)
	if tl != tr {
		if n.Addable == 0 {
			Tempname(&n1, n.Type)
			Complexmove(n, &n1)
			n = &n1
		}

		Complexmove(n, res)
		return
	}

	if res.Addable == 0 {
		Thearch.Igen(res, &n1, nil)
		Thearch.Cgen(n, &n1)
		Thearch.Regfree(&n1)
		return
	}

	if n.Addable != 0 {
		Complexmove(n, res)
		return
	}

	switch n.Op {
	default:
		Dump("complexgen: unknown op", n)
		Fatal("complexgen: unknown op %v", Oconv(int(n.Op), 0))

	case ODOT,
		ODOTPTR,
		OINDEX,
		OIND,
		ONAME, // PHEAP or PPARAMREF var
		OCALLFUNC,
		OCALLMETH,
		OCALLINTER:
		Thearch.Igen(n, &n1, res)

		Complexmove(&n1, res)
		Thearch.Regfree(&n1)
		return

	case OCONV,
		OADD,
		OSUB,
		OMUL,
		OMINUS,
		OCOMPLEX,
		OREAL,
		OIMAG:
		break
	}

	nl = n.Left
	if nl == nil {
		return
	}
	nr = n.Right

	// make both sides addable in ullman order
	if nr != nil {
		if nl.Ullman > nr.Ullman && nl.Addable == 0 {
			Tempname(&tnl, nl.Type)
			Thearch.Cgen(nl, &tnl)
			nl = &tnl
		}

		if nr.Addable == 0 {
			Tempname(&tnr, nr.Type)
			Thearch.Cgen(nr, &tnr)
			nr = &tnr
		}
	}

	if nl.Addable == 0 {
		Tempname(&tnl, nl.Type)
		Thearch.Cgen(nl, &tnl)
		nl = &tnl
	}

	switch n.Op {
	default:
		Fatal("complexgen: unknown op %v", Oconv(int(n.Op), 0))

	case OCONV:
		Complexmove(nl, res)

	case OMINUS:
		complexminus(nl, res)

	case OADD,
		OSUB:
		complexadd(int(n.Op), nl, nr, res)

	case OMUL:
		complexmul(nl, nr, res)
	}
}