liblink: create new library based on linker code

There is an enormous amount of code moving around in this CL,
but the code is the same, and it is invoked in the same ways.
This CL is preparation for the new linker structure, not the new
structure itself.

The new library's definition is in include/link.h.

The main change is the use of a Link structure to hold all the
linker-relevant state, replacing the smattering of global variables.
The Link structure should both make it clearer which state must
be carried around and make it possible to parallelize more easily
later.

The main body of the linker has moved into the architecture-independent
cmd/ld directory. That includes the list of known header types, so the
distinction between Hplan9x32 and Hplan9x64 is removed (no other
header type distinguished 32- and 64-bit formats), and code for unused
formats such as ipaq kernels has been deleted.

The code being deleted from 5l, 6l, and 8l reappears in liblink or in ld.
Because multiple files are being merged in the liblink directory,
it is not possible to show the diffs nicely in hg.

The Prog and Addr structures have been unified into an
architecture-independent form and moved to link.h, where they will
be shared by all tools: the assemblers, the compilers, and the linkers.
The unification makes it possible to write architecture-independent
traversal of Prog lists, among other benefits.

The Sym structures cannot be unified: they are too fundamentally
different between the linker and the compilers. Instead, liblink defines
an LSym - a linker Sym - to be used in the Prog and Addr structures,
and the linker now refers exclusively to LSyms. The compilers will
keep using their own syms but will fill out the corresponding LSyms in
the Prog and Addr structures.

Although code from 5l, 6l, and 8l is now in a single library, the
code has been arranged so that only one architecture needs to
be linked into a particular program: 5l will not contain the code
needed for x86 instruction layout, for example.

The object file writing code in liblink/obj.c is from cmd/gc/obj.c.

Preparation for golang.org/s/go13linker work.

This CL does not build by itself. It depends on 35740044
and will be submitted at the same time.

R=iant
CC=golang-dev
https://codereview.appspot.com/35790044

1 files changed, 0 insertions, 1507 deletions

diff --git a/src/cmd/8l/span.c b/src/cmd/8l/span.c
deleted file mode 100644
index acf973cab..000000000
--- a/src/cmd/8l/span.c
+++ /dev/null
@@ -1,1507 +0,0 @@
-// Inferno utils/8l/span.c
-// http://code.google.com/p/inferno-os/source/browse/utils/8l/span.c
-//
-//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
-//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
-//	Portions Copyright © 1997-1999 Vita Nuova Limited
-//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
-//	Portions Copyright © 2004,2006 Bruce Ellis
-//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
-//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
-//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-
-// Instruction layout.
-
-#include	"l.h"
-#include	"../ld/lib.h"
-#include	"../ld/elf.h"
-
-static int32	vaddr(Adr*, Reloc*);
-
-void
-span1(Sym *s)
-{
-	Prog *p, *q;
-	int32 c, v, loop;
-	uchar *bp;
-	int n, m, i;
-
-	cursym = s;
-
-	for(p = s->text; p != P; p = p->link) {
-		p->back = 2;	// use short branches first time through
-		if((q = p->pcond) != P && (q->back & 2))
-			p->back |= 1;	// backward jump
-
-		if(p->as == AADJSP) {
-			p->to.type = D_SP;
-			v = -p->from.offset;
-			p->from.offset = v;
-			p->as = AADDL;
-			if(v < 0) {
-				p->as = ASUBL;
-				v = -v;
-				p->from.offset = v;
-			}
-			if(v == 0)
-				p->as = ANOP;
-		}
-	}
-	
-	n = 0;
-	do {
-		loop = 0;
-		memset(s->r, 0, s->nr*sizeof s->r[0]);
-		s->nr = 0;
-		s->np = 0;
-		c = 0;
-		for(p = s->text; p != P; p = p->link) {
-			p->pc = c;
-
-			// process forward jumps to p
-			for(q = p->comefrom; q != P; q = q->forwd) {
-				v = p->pc - (q->pc + q->mark);
-				if(q->back & 2)	{	// short
-					if(v > 127) {
-						loop++;
-						q->back ^= 2;
-					}
-					if(q->as == AJCXZW)
-						s->p[q->pc+2] = v;
-					else
-						s->p[q->pc+1] = v;
-				} else {
-					bp = s->p + q->pc + q->mark - 4;
-					*bp++ = v;
-					*bp++ = v>>8;
-					*bp++ = v>>16;
-					*bp = v>>24;
-				}	
-			}
-			p->comefrom = P;
-
-			asmins(p);
-			p->pc = c;
-			m = andptr-and;
-			symgrow(s, p->pc+m);
-			memmove(s->p+p->pc, and, m);
-			p->mark = m;
-			c += m;
-		}
-		if(++n > 20) {
-			diag("span must be looping");
-			errorexit();
-		}
-	} while(loop);
-	s->size = c;
-
-	if(debug['a'] > 1) {
-		print("span1 %s %d (%d tries)\n %.6ux", s->name, s->size, n, 0);
-		for(i=0; i<s->np; i++) {
-			print(" %.2ux", s->p[i]);
-			if(i%16 == 15)
-				print("\n  %.6ux", i+1);
-		}
-		if(i%16)
-			print("\n");
-	
-		for(i=0; i<s->nr; i++) {
-			Reloc *r;
-			
-			r = &s->r[i];
-			print(" rel %#.4ux/%d %s%+d\n", r->off, r->siz, r->sym->name, r->add);
-		}
-	}
-}
-
-void
-span(void)
-{
-	Prog *p, *q;
-	int32 v;
-	int n;
-
-	if(debug['v'])
-		Bprint(&bso, "%5.2f span\n", cputime());
-
-	// NOTE(rsc): If we get rid of the globals we should
-	// be able to parallelize these iterations.
-	for(cursym = textp; cursym != nil; cursym = cursym->next) {
-		if(cursym->text == nil || cursym->text->link == nil)
-			continue;
-
-		// TODO: move into span1
-		for(p = cursym->text; p != P; p = p->link) {
-			n = 0;
-			if(p->to.type == D_BRANCH)
-				if(p->pcond == P)
-					p->pcond = p;
-			if((q = p->pcond) != P)
-				if(q->back != 2)
-					n = 1;
-			p->back = n;
-			if(p->as == AADJSP) {
-				p->to.type = D_SP;
-				v = -p->from.offset;
-				p->from.offset = v;
-				p->as = AADDL;
-				if(v < 0) {
-					p->as = ASUBL;
-					v = -v;
-					p->from.offset = v;
-				}
-				if(v == 0)
-					p->as = ANOP;
-			}
-		}
-		span1(cursym);
-	}
-}
-
-void
-xdefine(char *p, int t, int32 v)
-{
-	Sym *s;
-
-	s = lookup(p, 0);
-	s->type = t;
-	s->value = v;
-	s->reachable = 1;
-	s->special = 1;
-}
-
-void
-instinit(void)
-{
-	int i;
-
-	for(i=1; optab[i].as; i++)
-		if(i != optab[i].as) {
-			diag("phase error in optab: at %A found %A", i, optab[i].as);
-			errorexit();
-		}
-	maxop = i;
-
-	for(i=0; i<Ymax; i++)
-		ycover[i*Ymax + i] = 1;
-
-	ycover[Yi0*Ymax + Yi8] = 1;
-	ycover[Yi1*Ymax + Yi8] = 1;
-
-	ycover[Yi0*Ymax + Yi32] = 1;
-	ycover[Yi1*Ymax + Yi32] = 1;
-	ycover[Yi8*Ymax + Yi32] = 1;
-
-	ycover[Yal*Ymax + Yrb] = 1;
-	ycover[Ycl*Ymax + Yrb] = 1;
-	ycover[Yax*Ymax + Yrb] = 1;
-	ycover[Ycx*Ymax + Yrb] = 1;
-	ycover[Yrx*Ymax + Yrb] = 1;
-
-	ycover[Yax*Ymax + Yrx] = 1;
-	ycover[Ycx*Ymax + Yrx] = 1;
-
-	ycover[Yax*Ymax + Yrl] = 1;
-	ycover[Ycx*Ymax + Yrl] = 1;
-	ycover[Yrx*Ymax + Yrl] = 1;
-
-	ycover[Yf0*Ymax + Yrf] = 1;
-
-	ycover[Yal*Ymax + Ymb] = 1;
-	ycover[Ycl*Ymax + Ymb] = 1;
-	ycover[Yax*Ymax + Ymb] = 1;
-	ycover[Ycx*Ymax + Ymb] = 1;
-	ycover[Yrx*Ymax + Ymb] = 1;
-	ycover[Yrb*Ymax + Ymb] = 1;
-	ycover[Ym*Ymax + Ymb] = 1;
-
-	ycover[Yax*Ymax + Yml] = 1;
-	ycover[Ycx*Ymax + Yml] = 1;
-	ycover[Yrx*Ymax + Yml] = 1;
-	ycover[Yrl*Ymax + Yml] = 1;
-	ycover[Ym*Ymax + Yml] = 1;
-
-	ycover[Yax*Ymax + Ymm] = 1;
-	ycover[Ycx*Ymax + Ymm] = 1;
-	ycover[Yrx*Ymax + Ymm] = 1;
-	ycover[Yrl*Ymax + Ymm] = 1;
-	ycover[Ym*Ymax + Ymm] = 1;
-	ycover[Ymr*Ymax + Ymm] = 1;
-
-	ycover[Ym*Ymax + Yxm] = 1;
-	ycover[Yxr*Ymax + Yxm] = 1;
-
-	for(i=0; i<D_NONE; i++) {
-		reg[i] = -1;
-		if(i >= D_AL && i <= D_BH)
-			reg[i] = (i-D_AL) & 7;
-		if(i >= D_AX && i <= D_DI)
-			reg[i] = (i-D_AX) & 7;
-		if(i >= D_F0 && i <= D_F0+7)
-			reg[i] = (i-D_F0) & 7;
-		if(i >= D_X0 && i <= D_X0+7)
-			reg[i] = (i-D_X0) & 7;
-	}
-}
-
-int
-prefixof(Adr *a)
-{
-	switch(a->type) {
-	case D_INDIR+D_CS:
-		return 0x2e;
-	case D_INDIR+D_DS:
-		return 0x3e;
-	case D_INDIR+D_ES:
-		return 0x26;
-	case D_INDIR+D_FS:
-		return 0x64;
-	case D_INDIR+D_GS:
-		return 0x65;
-	}
-	return 0;
-}
-
-int
-oclass(Adr *a)
-{
-	int32 v;
-
-	if((a->type >= D_INDIR && a->type < 2*D_INDIR) || a->index != D_NONE) {
-		if(a->index != D_NONE && a->scale == 0) {
-			if(a->type == D_ADDR) {
-				switch(a->index) {
-				case D_EXTERN:
-				case D_STATIC:
-					return Yi32;
-				case D_AUTO:
-				case D_PARAM:
-					return Yiauto;
-				}
-				return Yxxx;
-			}
-			//if(a->type == D_INDIR+D_ADDR)
-			//	print("*Ycol\n");
-			return Ycol;
-		}
-		return Ym;
-	}
-	switch(a->type)
-	{
-	case D_AL:
-		return Yal;
-
-	case D_AX:
-		return Yax;
-
-	case D_CL:
-	case D_DL:
-	case D_BL:
-	case D_AH:
-	case D_CH:
-	case D_DH:
-	case D_BH:
-		return Yrb;
-
-	case D_CX:
-		return Ycx;
-
-	case D_DX:
-	case D_BX:
-		return Yrx;
-
-	case D_SP:
-	case D_BP:
-	case D_SI:
-	case D_DI:
-		return Yrl;
-
-	case D_F0+0:
-		return	Yf0;
-
-	case D_F0+1:
-	case D_F0+2:
-	case D_F0+3:
-	case D_F0+4:
-	case D_F0+5:
-	case D_F0+6:
-	case D_F0+7:
-		return	Yrf;
-
-	case D_X0+0:
-	case D_X0+1:
-	case D_X0+2:
-	case D_X0+3:
-	case D_X0+4:
-	case D_X0+5:
-	case D_X0+6:
-	case D_X0+7:
-		return	Yxr;
-
-	case D_NONE:
-		return Ynone;
-
-	case D_CS:	return	Ycs;
-	case D_SS:	return	Yss;
-	case D_DS:	return	Yds;
-	case D_ES:	return	Yes;
-	case D_FS:	return	Yfs;
-	case D_GS:	return	Ygs;
-
-	case D_GDTR:	return	Ygdtr;
-	case D_IDTR:	return	Yidtr;
-	case D_LDTR:	return	Yldtr;
-	case D_MSW:	return	Ymsw;
-	case D_TASK:	return	Ytask;
-
-	case D_CR+0:	return	Ycr0;
-	case D_CR+1:	return	Ycr1;
-	case D_CR+2:	return	Ycr2;
-	case D_CR+3:	return	Ycr3;
-	case D_CR+4:	return	Ycr4;
-	case D_CR+5:	return	Ycr5;
-	case D_CR+6:	return	Ycr6;
-	case D_CR+7:	return	Ycr7;
-
-	case D_DR+0:	return	Ydr0;
-	case D_DR+1:	return	Ydr1;
-	case D_DR+2:	return	Ydr2;
-	case D_DR+3:	return	Ydr3;
-	case D_DR+4:	return	Ydr4;
-	case D_DR+5:	return	Ydr5;
-	case D_DR+6:	return	Ydr6;
-	case D_DR+7:	return	Ydr7;
-
-	case D_TR+0:	return	Ytr0;
-	case D_TR+1:	return	Ytr1;
-	case D_TR+2:	return	Ytr2;
-	case D_TR+3:	return	Ytr3;
-	case D_TR+4:	return	Ytr4;
-	case D_TR+5:	return	Ytr5;
-	case D_TR+6:	return	Ytr6;
-	case D_TR+7:	return	Ytr7;
-
-	case D_EXTERN:
-	case D_STATIC:
-	case D_AUTO:
-	case D_PARAM:
-		return Ym;
-
-	case D_CONST:
-	case D_CONST2:
-	case D_ADDR:
-		if(a->sym == S) {
-			v = a->offset;
-			if(v == 0)
-				return Yi0;
-			if(v == 1)
-				return Yi1;
-			if(v >= -128 && v <= 127)
-				return Yi8;
-		}
-		return Yi32;
-
-	case D_BRANCH:
-		return Ybr;
-	}
-	return Yxxx;
-}
-
-void
-asmidx(int scale, int index, int base)
-{
-	int i;
-
-	switch(index) {
-	default:
-		goto bad;
-
-	case D_NONE:
-		i = 4 << 3;
-		goto bas;
-
-	case D_AX:
-	case D_CX:
-	case D_DX:
-	case D_BX:
-	case D_BP:
-	case D_SI:
-	case D_DI:
-		i = reg[index] << 3;
-		break;
-	}
-	switch(scale) {
-	default:
-		goto bad;
-	case 1:
-		break;
-	case 2:
-		i |= (1<<6);
-		break;
-	case 4:
-		i |= (2<<6);
-		break;
-	case 8:
-		i |= (3<<6);
-		break;
-	}
-bas:
-	switch(base) {
-	default:
-		goto bad;
-	case D_NONE:	/* must be mod=00 */
-		i |= 5;
-		break;
-	case D_AX:
-	case D_CX:
-	case D_DX:
-	case D_BX:
-	case D_SP:
-	case D_BP:
-	case D_SI:
-	case D_DI:
-		i |= reg[base];
-		break;
-	}
-	*andptr++ = i;
-	return;
-bad:
-	diag("asmidx: bad address %d,%d,%d", scale, index, base);
-	*andptr++ = 0;
-	return;
-}
-
-static void
-put4(int32 v)
-{
-	andptr[0] = v;
-	andptr[1] = v>>8;
-	andptr[2] = v>>16;
-	andptr[3] = v>>24;
-	andptr += 4;
-}
-
-static void
-relput4(Prog *p, Adr *a)
-{
-	vlong v;
-	Reloc rel, *r;
-	
-	v = vaddr(a, &rel);
-	if(rel.siz != 0) {
-		if(rel.siz != 4)
-			diag("bad reloc");
-		r = addrel(cursym);
-		*r = rel;
-		r->off = p->pc + andptr - and;
-	}
-	put4(v);
-}
-
-int32
-symaddr(Sym *s)
-{
-	if(!s->reachable)
-		diag("unreachable symbol in symaddr - %s", s->name);
-	return s->value;
-}
-
-static int32
-vaddr(Adr *a, Reloc *r)
-{
-	int t;
-	int32 v;
-	Sym *s;
-	
-	if(r != nil)
-		memset(r, 0, sizeof *r);
-
-	t = a->type;
-	v = a->offset;
-	if(t == D_ADDR)
-		t = a->index;
-	switch(t) {
-	case D_STATIC:
-	case D_EXTERN:
-		s = a->sym;
-		if(s != nil) {
-			if(!s->reachable)
-				sysfatal("unreachable symbol in vaddr - %s", s->name);
-			if(r == nil) {
-				diag("need reloc for %D", a);
-				errorexit();
-			}
-			r->type = D_ADDR;
-			r->siz = 4;
-			r->off = -1;
-			r->sym = s;
-			r->add = v;
-			v = 0;
-		}
-	}
-	return v;
-}
-
-static int
-istls(Adr *a)
-{
-	if(HEADTYPE == Hlinux)
-		return a->index == D_GS;
-	return a->type == D_INDIR+D_GS;
-}
-
-void
-asmand(Adr *a, int r)
-{
-	int32 v;
-	int t, scale;
-	Reloc rel;
-
-	v = a->offset;
-	t = a->type;
-	rel.siz = 0;
-	if(a->index != D_NONE && a->index != D_FS && a->index != D_GS) {
-		if(t < D_INDIR || t >= 2*D_INDIR) {
-			switch(t) {
-			default:
-				goto bad;
-			case D_STATIC:
-			case D_EXTERN:
-				t = D_NONE;
-				v = vaddr(a, &rel);
-				break;
-			case D_AUTO:
-			case D_PARAM:
-				t = D_SP;
-				break;
-			}
-		} else
-			t -= D_INDIR;
-
-		if(t == D_NONE) {
-			*andptr++ = (0 << 6) | (4 << 0) | (r << 3);
-			asmidx(a->scale, a->index, t);
-			goto putrelv;
-		}
-		if(v == 0 && rel.siz == 0 && t != D_BP) {
-			*andptr++ = (0 << 6) | (4 << 0) | (r << 3);
-			asmidx(a->scale, a->index, t);
-			return;
-		}
-		if(v >= -128 && v < 128 && rel.siz == 0) {
-			*andptr++ = (1 << 6) | (4 << 0) | (r << 3);
-			asmidx(a->scale, a->index, t);
-			*andptr++ = v;
-			return;
-		}
-		*andptr++ = (2 << 6) | (4 << 0) | (r << 3);
-		asmidx(a->scale, a->index, t);
-		goto putrelv;
-	}
-	if(t >= D_AL && t <= D_F7 || t >= D_X0 && t <= D_X7) {
-		if(v)
-			goto bad;
-		*andptr++ = (3 << 6) | (reg[t] << 0) | (r << 3);
-		return;
-	}
-	
-	scale = a->scale;
-	if(t < D_INDIR || t >= 2*D_INDIR) {
-		switch(a->type) {
-		default:
-			goto bad;
-		case D_STATIC:
-		case D_EXTERN:
-			t = D_NONE;
-			v = vaddr(a, &rel);
-			break;
-		case D_AUTO:
-		case D_PARAM:
-			t = D_SP;
-			break;
-		}
-		scale = 1;
-	} else
-		t -= D_INDIR;
-
-	if(t == D_NONE || (D_CS <= t && t <= D_GS)) {
-		*andptr++ = (0 << 6) | (5 << 0) | (r << 3);
-		goto putrelv;
-	}
-	if(t == D_SP) {
-		if(v == 0 && rel.siz == 0) {
-			*andptr++ = (0 << 6) | (4 << 0) | (r << 3);
-			asmidx(scale, D_NONE, t);
-			return;
-		}
-		if(v >= -128 && v < 128 && rel.siz == 0) {
-			*andptr++ = (1 << 6) | (4 << 0) | (r << 3);
-			asmidx(scale, D_NONE, t);
-			*andptr++ = v;
-			return;
-		}
-		*andptr++ = (2 << 6) | (4 << 0) | (r << 3);
-		asmidx(scale, D_NONE, t);
-		goto putrelv;
-	}
-	if(t >= D_AX && t <= D_DI) {
-		if(v == 0 && rel.siz == 0 && t != D_BP) {
-			*andptr++ = (0 << 6) | (reg[t] << 0) | (r << 3);
-			return;
-		}
-		if(v >= -128 && v < 128 && rel.siz == 0 && a->index != D_FS && a->index != D_GS) {
-			andptr[0] = (1 << 6) | (reg[t] << 0) | (r << 3);
-			andptr[1] = v;
-			andptr += 2;
-			return;
-		}
-		*andptr++ = (2 << 6) | (reg[t] << 0) | (r << 3);
-		goto putrelv;
-	}
-	goto bad;
-
-putrelv:
-	if(rel.siz != 0) {
-		Reloc *r;
-		
-		if(rel.siz != 4) {
-			diag("bad rel");
-			goto bad;
-		}
-		r = addrel(cursym);
-		*r = rel;
-		r->off = curp->pc + andptr - and;
-	} else if(iself && linkmode == LinkExternal && istls(a) && HEADTYPE != Hopenbsd) {
-		Reloc *r;
-		Sym *s;
-
-		r = addrel(cursym);
-		r->off = curp->pc + andptr - and;
-		r->add = a->offset-tlsoffset;
-		r->xadd = r->add;
-		r->siz = 4;
-		r->type = D_TLS;
-		s = lookup("runtime.tlsgm", 0);
-		r->sym = s;
-		r->xsym = s;
-		v = 0;
-	}
-
-	put4(v);
-	return;
-
-bad:
-	diag("asmand: bad address %D", a);
-	return;
-}
-
-#define	E	0xff
-uchar	ymovtab[] =
-{
-/* push */
-	APUSHL,	Ycs,	Ynone,	0,	0x0e,E,0,0,
-	APUSHL,	Yss,	Ynone,	0,	0x16,E,0,0,
-	APUSHL,	Yds,	Ynone,	0,	0x1e,E,0,0,
-	APUSHL,	Yes,	Ynone,	0,	0x06,E,0,0,
-	APUSHL,	Yfs,	Ynone,	0,	0x0f,0xa0,E,0,
-	APUSHL,	Ygs,	Ynone,	0,	0x0f,0xa8,E,0,
-
-	APUSHW,	Ycs,	Ynone,	0,	Pe,0x0e,E,0,
-	APUSHW,	Yss,	Ynone,	0,	Pe,0x16,E,0,
-	APUSHW,	Yds,	Ynone,	0,	Pe,0x1e,E,0,
-	APUSHW,	Yes,	Ynone,	0,	Pe,0x06,E,0,
-	APUSHW,	Yfs,	Ynone,	0,	Pe,0x0f,0xa0,E,
-	APUSHW,	Ygs,	Ynone,	0,	Pe,0x0f,0xa8,E,
-
-/* pop */
-	APOPL,	Ynone,	Yds,	0,	0x1f,E,0,0,
-	APOPL,	Ynone,	Yes,	0,	0x07,E,0,0,
-	APOPL,	Ynone,	Yss,	0,	0x17,E,0,0,
-	APOPL,	Ynone,	Yfs,	0,	0x0f,0xa1,E,0,
-	APOPL,	Ynone,	Ygs,	0,	0x0f,0xa9,E,0,
-
-	APOPW,	Ynone,	Yds,	0,	Pe,0x1f,E,0,
-	APOPW,	Ynone,	Yes,	0,	Pe,0x07,E,0,
-	APOPW,	Ynone,	Yss,	0,	Pe,0x17,E,0,
-	APOPW,	Ynone,	Yfs,	0,	Pe,0x0f,0xa1,E,
-	APOPW,	Ynone,	Ygs,	0,	Pe,0x0f,0xa9,E,
-
-/* mov seg */
-	AMOVW,	Yes,	Yml,	1,	0x8c,0,0,0,
-	AMOVW,	Ycs,	Yml,	1,	0x8c,1,0,0,
-	AMOVW,	Yss,	Yml,	1,	0x8c,2,0,0,
-	AMOVW,	Yds,	Yml,	1,	0x8c,3,0,0,
-	AMOVW,	Yfs,	Yml,	1,	0x8c,4,0,0,
-	AMOVW,	Ygs,	Yml,	1,	0x8c,5,0,0,
-
-	AMOVW,	Yml,	Yes,	2,	0x8e,0,0,0,
-	AMOVW,	Yml,	Ycs,	2,	0x8e,1,0,0,
-	AMOVW,	Yml,	Yss,	2,	0x8e,2,0,0,
-	AMOVW,	Yml,	Yds,	2,	0x8e,3,0,0,
-	AMOVW,	Yml,	Yfs,	2,	0x8e,4,0,0,
-	AMOVW,	Yml,	Ygs,	2,	0x8e,5,0,0,
-
-/* mov cr */
-	AMOVL,	Ycr0,	Yml,	3,	0x0f,0x20,0,0,
-	AMOVL,	Ycr2,	Yml,	3,	0x0f,0x20,2,0,
-	AMOVL,	Ycr3,	Yml,	3,	0x0f,0x20,3,0,
-	AMOVL,	Ycr4,	Yml,	3,	0x0f,0x20,4,0,
-
-	AMOVL,	Yml,	Ycr0,	4,	0x0f,0x22,0,0,
-	AMOVL,	Yml,	Ycr2,	4,	0x0f,0x22,2,0,
-	AMOVL,	Yml,	Ycr3,	4,	0x0f,0x22,3,0,
-	AMOVL,	Yml,	Ycr4,	4,	0x0f,0x22,4,0,
-
-/* mov dr */
-	AMOVL,	Ydr0,	Yml,	3,	0x0f,0x21,0,0,
-	AMOVL,	Ydr6,	Yml,	3,	0x0f,0x21,6,0,
-	AMOVL,	Ydr7,	Yml,	3,	0x0f,0x21,7,0,
-
-	AMOVL,	Yml,	Ydr0,	4,	0x0f,0x23,0,0,
-	AMOVL,	Yml,	Ydr6,	4,	0x0f,0x23,6,0,
-	AMOVL,	Yml,	Ydr7,	4,	0x0f,0x23,7,0,
-
-/* mov tr */
-	AMOVL,	Ytr6,	Yml,	3,	0x0f,0x24,6,0,
-	AMOVL,	Ytr7,	Yml,	3,	0x0f,0x24,7,0,
-
-	AMOVL,	Yml,	Ytr6,	4,	0x0f,0x26,6,E,
-	AMOVL,	Yml,	Ytr7,	4,	0x0f,0x26,7,E,
-
-/* lgdt, sgdt, lidt, sidt */
-	AMOVL,	Ym,	Ygdtr,	4,	0x0f,0x01,2,0,
-	AMOVL,	Ygdtr,	Ym,	3,	0x0f,0x01,0,0,
-	AMOVL,	Ym,	Yidtr,	4,	0x0f,0x01,3,0,
-	AMOVL,	Yidtr,	Ym,	3,	0x0f,0x01,1,0,
-
-/* lldt, sldt */
-	AMOVW,	Yml,	Yldtr,	4,	0x0f,0x00,2,0,
-	AMOVW,	Yldtr,	Yml,	3,	0x0f,0x00,0,0,
-
-/* lmsw, smsw */
-	AMOVW,	Yml,	Ymsw,	4,	0x0f,0x01,6,0,
-	AMOVW,	Ymsw,	Yml,	3,	0x0f,0x01,4,0,
-
-/* ltr, str */
-	AMOVW,	Yml,	Ytask,	4,	0x0f,0x00,3,0,
-	AMOVW,	Ytask,	Yml,	3,	0x0f,0x00,1,0,
-
-/* load full pointer */
-	AMOVL,	Yml,	Ycol,	5,	0,0,0,0,
-	AMOVW,	Yml,	Ycol,	5,	Pe,0,0,0,
-
-/* double shift */
-	ASHLL,	Ycol,	Yml,	6,	0xa4,0xa5,0,0,
-	ASHRL,	Ycol,	Yml,	6,	0xac,0xad,0,0,
-
-/* extra imul */
-	AIMULW,	Yml,	Yrl,	7,	Pq,0xaf,0,0,
-	AIMULL,	Yml,	Yrl,	7,	Pm,0xaf,0,0,
-	0
-};
-
-// byteswapreg returns a byte-addressable register (AX, BX, CX, DX)
-// which is not referenced in a->type.
-// If a is empty, it returns BX to account for MULB-like instructions
-// that might use DX and AX.
-int
-byteswapreg(Adr *a)
-{
-	int cana, canb, canc, cand;
-
-	cana = canb = canc = cand = 1;
-
-	switch(a->type) {
-	case D_NONE:
-		cana = cand = 0;
-		break;
-	case D_AX:
-	case D_AL:
-	case D_AH:
-	case D_INDIR+D_AX:
-		cana = 0;
-		break;
-	case D_BX:
-	case D_BL:
-	case D_BH:
-	case D_INDIR+D_BX:
-		canb = 0;
-		break;
-	case D_CX:
-	case D_CL:
-	case D_CH:
-	case D_INDIR+D_CX:
-		canc = 0;
-		break;
-	case D_DX:
-	case D_DL:
-	case D_DH:
-	case D_INDIR+D_DX:
-		cand = 0;
-		break;
-	}
-	switch(a->index) {
-	case D_AX:
-		cana = 0;
-		break;
-	case D_BX:
-		canb = 0;
-		break;
-	case D_CX:
-		canc = 0;
-		break;
-	case D_DX:
-		cand = 0;
-		break;
-	}
-	if(cana)
-		return D_AX;
-	if(canb)
-		return D_BX;
-	if(canc)
-		return D_CX;
-	if(cand)
-		return D_DX;
-
-	diag("impossible byte register");
-	errorexit();
-	return 0;
-}
-
-void
-subreg(Prog *p, int from, int to)
-{
-
-	if(debug['Q'])
-		print("\n%P	s/%R/%R/\n", p, from, to);
-
-	if(p->from.type == from) {
-		p->from.type = to;
-		p->ft = 0;
-	}
-	if(p->to.type == from) {
-		p->to.type = to;
-		p->tt = 0;
-	}
-
-	if(p->from.index == from) {
-		p->from.index = to;
-		p->ft = 0;
-	}
-	if(p->to.index == from) {
-		p->to.index = to;
-		p->tt = 0;
-	}
-
-	from += D_INDIR;
-	if(p->from.type == from) {
-		p->from.type = to+D_INDIR;
-		p->ft = 0;
-	}
-	if(p->to.type == from) {
-		p->to.type = to+D_INDIR;
-		p->tt = 0;
-	}
-
-	if(debug['Q'])
-		print("%P\n", p);
-}
-
-static int
-mediaop(Optab *o, int op, int osize, int z)
-{
-	switch(op){
-	case Pm:
-	case Pe:
-	case Pf2:
-	case Pf3:
-		if(osize != 1){
-			if(op != Pm)
-				*andptr++ = op;
-			*andptr++ = Pm;
-			op = o->op[++z];
-			break;
-		}
-	default:
-		if(andptr == and || andptr[-1] != Pm)
-			*andptr++ = Pm;
-		break;
-	}
-	*andptr++ = op;
-	return z;
-}
-
-void
-doasm(Prog *p)
-{
-	Optab *o;
-	Prog *q, pp;
-	uchar *t;
-	int z, op, ft, tt, breg;
-	int32 v, pre;
-	Reloc rel, *r;
-	Adr *a;
-	
-	curp = p;	// TODO
-
-	pre = prefixof(&p->from);
-	if(pre)
-		*andptr++ = pre;
-	pre = prefixof(&p->to);
-	if(pre)
-		*andptr++ = pre;
-
-	if(p->ft == 0)
-		p->ft = oclass(&p->from);
-	if(p->tt == 0)
-		p->tt = oclass(&p->to);
-
-	ft = p->ft * Ymax;
-	tt = p->tt * Ymax;
-	o = &optab[p->as];
-	t = o->ytab;
-	if(t == 0) {
-		diag("asmins: noproto %P", p);
-		return;
-	}
-	for(z=0; *t; z+=t[3],t+=4)
-		if(ycover[ft+t[0]])
-		if(ycover[tt+t[1]])
-			goto found;
-	goto domov;
-
-found:
-	switch(o->prefix) {
-	case Pq:	/* 16 bit escape and opcode escape */
-		*andptr++ = Pe;
-		*andptr++ = Pm;
-		break;
-
-	case Pf2:	/* xmm opcode escape */
-	case Pf3:
-		*andptr++ = o->prefix;
-		*andptr++ = Pm;
-		break;
-
-	case Pm:	/* opcode escape */
-		*andptr++ = Pm;
-		break;
-
-	case Pe:	/* 16 bit escape */
-		*andptr++ = Pe;
-		break;
-
-	case Pb:	/* botch */
-		break;
-	}
-
-	op = o->op[z];
-	switch(t[2]) {
-	default:
-		diag("asmins: unknown z %d %P", t[2], p);
-		return;
-
-	case Zpseudo:
-		break;
-
-	case Zlit:
-		for(; op = o->op[z]; z++)
-			*andptr++ = op;
-		break;
-
-	case Zlitm_r:
-		for(; op = o->op[z]; z++)
-			*andptr++ = op;
-		asmand(&p->from, reg[p->to.type]);
-		break;
-
-	case Zm_r:
-		*andptr++ = op;
-		asmand(&p->from, reg[p->to.type]);
-		break;
-
-	case Zm2_r:
-		*andptr++ = op;
-		*andptr++ = o->op[z+1];
-		asmand(&p->from, reg[p->to.type]);
-		break;
-
-	case Zm_r_xm:
-		mediaop(o, op, t[3], z);
-		asmand(&p->from, reg[p->to.type]);
-		break;
-
-	case Zm_r_i_xm:
-		mediaop(o, op, t[3], z);
-		asmand(&p->from, reg[p->to.type]);
-		*andptr++ = p->to.offset;
-		break;
-
-	case Zibm_r:
-		while ((op = o->op[z++]) != 0)
-			*andptr++ = op;
-		asmand(&p->from, reg[p->to.type]);
-		*andptr++ = p->to.offset;
-		break;
-
-	case Zaut_r:
-		*andptr++ = 0x8d;	/* leal */
-		if(p->from.type != D_ADDR)
-			diag("asmins: Zaut sb type ADDR");
-		p->from.type = p->from.index;
-		p->from.index = D_NONE;
-		p->ft = 0;
-		asmand(&p->from, reg[p->to.type]);
-		p->from.index = p->from.type;
-		p->from.type = D_ADDR;
-		p->ft = 0;
-		break;
-
-	case Zm_o:
-		*andptr++ = op;
-		asmand(&p->from, o->op[z+1]);
-		break;
-
-	case Zr_m:
-		*andptr++ = op;
-		asmand(&p->to, reg[p->from.type]);
-		break;
-
-	case Zr_m_xm:
-		mediaop(o, op, t[3], z);
-		asmand(&p->to, reg[p->from.type]);
-		break;
-
-	case Zr_m_i_xm:
-		mediaop(o, op, t[3], z);
-		asmand(&p->to, reg[p->from.type]);
-		*andptr++ = p->from.offset;
-		break;
-
-	case Zo_m:
-		*andptr++ = op;
-		asmand(&p->to, o->op[z+1]);
-		break;
-
-	case Zm_ibo:
-		*andptr++ = op;
-		asmand(&p->from, o->op[z+1]);
-		*andptr++ = vaddr(&p->to, nil);
-		break;
-
-	case Zibo_m:
-		*andptr++ = op;
-		asmand(&p->to, o->op[z+1]);
-		*andptr++ = vaddr(&p->from, nil);
-		break;
-
-	case Z_ib:
-	case Zib_:
-		if(t[2] == Zib_)
-			a = &p->from;
-		else
-			a = &p->to;
-		v = vaddr(a, nil);
-		*andptr++ = op;
-		*andptr++ = v;
-		break;
-
-	case Zib_rp:
-		*andptr++ = op + reg[p->to.type];
-		*andptr++ = vaddr(&p->from, nil);
-		break;
-
-	case Zil_rp:
-		*andptr++ = op + reg[p->to.type];
-		if(o->prefix == Pe) {
-			v = vaddr(&p->from, nil);
-			*andptr++ = v;
-			*andptr++ = v>>8;
-		}
-		else
-			relput4(p, &p->from);
-		break;
-
-	case Zib_rr:
-		*andptr++ = op;
-		asmand(&p->to, reg[p->to.type]);
-		*andptr++ = vaddr(&p->from, nil);
-		break;
-
-	case Z_il:
-	case Zil_:
-		if(t[2] == Zil_)
-			a = &p->from;
-		else
-			a = &p->to;
-		*andptr++ = op;
-		if(o->prefix == Pe) {
-			v = vaddr(a, nil);
-			*andptr++ = v;
-			*andptr++ = v>>8;
-		}
-		else
-			relput4(p, a);
-		break;
-
-	case Zm_ilo:
-	case Zilo_m:
-		*andptr++ = op;
-		if(t[2] == Zilo_m) {
-			a = &p->from;
-			asmand(&p->to, o->op[z+1]);
-		} else {
-			a = &p->to;
-			asmand(&p->from, o->op[z+1]);
-		}
-		if(o->prefix == Pe) {
-			v = vaddr(a, nil);
-			*andptr++ = v;
-			*andptr++ = v>>8;
-		}
-		else
-			relput4(p, a);
-		break;
-
-	case Zil_rr:
-		*andptr++ = op;
-		asmand(&p->to, reg[p->to.type]);
-		if(o->prefix == Pe) {
-			v = vaddr(&p->from, nil);
-			*andptr++ = v;
-			*andptr++ = v>>8;
-		}
-		else
-			relput4(p, &p->from);
-		break;
-
-	case Z_rp:
-		*andptr++ = op + reg[p->to.type];
-		break;
-
-	case Zrp_:
-		*andptr++ = op + reg[p->from.type];
-		break;
-
-	case Zclr:
-		*andptr++ = op;
-		asmand(&p->to, reg[p->to.type]);
-		break;
-	
-	case Zcall:
-		q = p->pcond;
-		if(q == nil) {
-			diag("call without target");
-			errorexit();
-		}
-		if(q->as != ATEXT) {
-			// Could handle this case by making D_PCREL
-			// record the Prog* instead of the Sym*, but let's
-			// wait until the need arises.
-			diag("call of non-TEXT %P", q);
-			errorexit();
-		}
-		*andptr++ = op;
-		r = addrel(cursym);
-		r->off = p->pc + andptr - and;
-		r->type = D_PCREL;
-		r->siz = 4;
-		r->sym = q->from.sym;
-		put4(0);
-		break;
-
-	case Zbr:
-	case Zjmp:
-	case Zloop:
-		q = p->pcond;
-		if(q == nil) {
-			diag("jmp/branch/loop without target");
-			errorexit();
-		}
-		if(q->as == ATEXT) {
-			// jump out of function
-			if(t[2] == Zbr) {
-				diag("branch to ATEXT");
-				errorexit();
-			}
-			*andptr++ = o->op[z+1];
-			r = addrel(cursym);
-			r->off = p->pc + andptr - and;
-			r->sym = q->from.sym;
-			r->type = D_PCREL;
-			r->siz = 4;
-			put4(0);
-			break;
-		}
-		
-		// Assumes q is in this function.
-		// TODO: Check in input, preserve in brchain.
-		
-		// Fill in backward jump now.
-		if(p->back & 1) {
-			v = q->pc - (p->pc + 2);
-			if(v >= -128) {
-				if(p->as == AJCXZW)
-					*andptr++ = 0x67;
-				*andptr++ = op;
-				*andptr++ = v;
-			} else if(t[2] == Zloop) {
-				diag("loop too far: %P", p);
-			} else {
-				v -= 5-2;
-				if(t[2] == Zbr) {
-					*andptr++ = 0x0f;
-					v--;
-				}
-				*andptr++ = o->op[z+1];
-				*andptr++ = v;
-				*andptr++ = v>>8;
-				*andptr++ = v>>16;
-				*andptr++ = v>>24;
-			}
-			break;
-		}
-
-		// Annotate target; will fill in later.
-		p->forwd = q->comefrom;
-		q->comefrom = p;
-		if(p->back & 2)	{ // short
-			if(p->as == AJCXZW)
-				*andptr++ = 0x67;
-			*andptr++ = op;
-			*andptr++ = 0;
-		} else if(t[2] == Zloop) {
-			diag("loop too far: %P", p);
-		} else {
-			if(t[2] == Zbr)
-				*andptr++ = 0x0f;
-			*andptr++ = o->op[z+1];
-			*andptr++ = 0;
-			*andptr++ = 0;
-			*andptr++ = 0;
-			*andptr++ = 0;
-		}
-		break;
-
-	case Zcallcon:
-	case Zjmpcon:
-		if(t[2] == Zcallcon)
-			*andptr++ = op;
-		else
-			*andptr++ = o->op[z+1];
-		r = addrel(cursym);
-		r->off = p->pc + andptr - and;
-		r->type = D_PCREL;
-		r->siz = 4;
-		r->add = p->to.offset;
-		put4(0);
-		break;
-	
-	case Zcallind:
-		*andptr++ = op;
-		*andptr++ = o->op[z+1];
-		r = addrel(cursym);
-		r->off = p->pc + andptr - and;
-		r->type = D_ADDR;
-		r->siz = 4;
-		r->add = p->to.offset;
-		r->sym = p->to.sym;
-		put4(0);
-		break;
-
-	case Zbyte:
-		v = vaddr(&p->from, &rel);
-		if(rel.siz != 0) {
-			rel.siz = op;
-			r = addrel(cursym);
-			*r = rel;
-			r->off = p->pc + andptr - and;
-		}
-		*andptr++ = v;
-		if(op > 1) {
-			*andptr++ = v>>8;
-			if(op > 2) {
-				*andptr++ = v>>16;
-				*andptr++ = v>>24;
-			}
-		}
-		break;
-
-	case Zmov:
-		goto domov;
-	}
-	return;
-
-domov:
-	for(t=ymovtab; *t; t+=8)
-		if(p->as == t[0])
-		if(ycover[ft+t[1]])
-		if(ycover[tt+t[2]])
-			goto mfound;
-bad:
-	/*
-	 * here, the assembly has failed.
-	 * if its a byte instruction that has
-	 * unaddressable registers, try to
-	 * exchange registers and reissue the
-	 * instruction with the operands renamed.
-	 */
-	pp = *p;
-	z = p->from.type;
-	if(z >= D_BP && z <= D_DI) {
-		if((breg = byteswapreg(&p->to)) != D_AX) {
-			*andptr++ = 0x87;			/* xchg lhs,bx */
-			asmand(&p->from, reg[breg]);
-			subreg(&pp, z, breg);
-			doasm(&pp);
-			*andptr++ = 0x87;			/* xchg lhs,bx */
-			asmand(&p->from, reg[breg]);
-		} else {
-			*andptr++ = 0x90 + reg[z];		/* xchg lsh,ax */
-			subreg(&pp, z, D_AX);
-			doasm(&pp);
-			*andptr++ = 0x90 + reg[z];		/* xchg lsh,ax */
-		}
-		return;
-	}
-	z = p->to.type;
-	if(z >= D_BP && z <= D_DI) {
-		if((breg = byteswapreg(&p->from)) != D_AX) {
-			*andptr++ = 0x87;			/* xchg rhs,bx */
-			asmand(&p->to, reg[breg]);
-			subreg(&pp, z, breg);
-			doasm(&pp);
-			*andptr++ = 0x87;			/* xchg rhs,bx */
-			asmand(&p->to, reg[breg]);
-		} else {
-			*andptr++ = 0x90 + reg[z];		/* xchg rsh,ax */
-			subreg(&pp, z, D_AX);
-			doasm(&pp);
-			*andptr++ = 0x90 + reg[z];		/* xchg rsh,ax */
-		}
-		return;
-	}
-	diag("doasm: notfound t2=%ux from=%ux to=%ux %P", t[2], p->from.type, p->to.type, p);
-	return;
-
-mfound:
-	switch(t[3]) {
-	default:
-		diag("asmins: unknown mov %d %P", t[3], p);
-		break;
-
-	case 0:	/* lit */
-		for(z=4; t[z]!=E; z++)
-			*andptr++ = t[z];
-		break;
-
-	case 1:	/* r,m */
-		*andptr++ = t[4];
-		asmand(&p->to, t[5]);
-		break;
-
-	case 2:	/* m,r */
-		*andptr++ = t[4];
-		asmand(&p->from, t[5]);
-		break;
-
-	case 3:	/* r,m - 2op */
-		*andptr++ = t[4];
-		*andptr++ = t[5];
-		asmand(&p->to, t[6]);
-		break;
-
-	case 4:	/* m,r - 2op */
-		*andptr++ = t[4];
-		*andptr++ = t[5];
-		asmand(&p->from, t[6]);
-		break;
-
-	case 5:	/* load full pointer, trash heap */
-		if(t[4])
-			*andptr++ = t[4];
-		switch(p->to.index) {
-		default:
-			goto bad;
-		case D_DS:
-			*andptr++ = 0xc5;
-			break;
-		case D_SS:
-			*andptr++ = 0x0f;
-			*andptr++ = 0xb2;
-			break;
-		case D_ES:
-			*andptr++ = 0xc4;
-			break;
-		case D_FS:
-			*andptr++ = 0x0f;
-			*andptr++ = 0xb4;
-			break;
-		case D_GS:
-			*andptr++ = 0x0f;
-			*andptr++ = 0xb5;
-			break;
-		}
-		asmand(&p->from, reg[p->to.type]);
-		break;
-
-	case 6:	/* double shift */
-		z = p->from.type;
-		switch(z) {
-		default:
-			goto bad;
-		case D_CONST:
-			*andptr++ = 0x0f;
-			*andptr++ = t[4];
-			asmand(&p->to, reg[p->from.index]);
-			*andptr++ = p->from.offset;
-			break;
-		case D_CL:
-		case D_CX:
-			*andptr++ = 0x0f;
-			*andptr++ = t[5];
-			asmand(&p->to, reg[p->from.index]);
-			break;
-		}
-		break;
-
-	case 7: /* imul rm,r */
-		if(t[4] == Pq) {
-			*andptr++ = Pe;
-			*andptr++ = Pm;
-		} else
-			*andptr++ = t[4];
-		*andptr++ = t[5];
-		asmand(&p->from, reg[p->to.type]);
-		break;
-	}
-}
-
-void
-asmins(Prog *p)
-{
-	andptr = and;
-	doasm(p);
-	if(andptr > and+sizeof and) {
-		print("and[] is too short - %ld byte instruction\n", andptr - and);
-		errorexit();
-	}
-}