blob: 8a55ffd5987239f642ed9195549b08c229f4b157 [file] [log] [blame]
// 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.
#undef EXTERN
#define EXTERN
#include "gg.h"
#include "opt.h"
static Prog *pret;
static Node *naclnop;
void
compile(Node *fn)
{
Plist *pl;
Node nod1;
Prog *ptxt;
int32 lno;
Type *t;
Iter save;
if(newproc == N) {
newproc = sysfunc("newproc");
deferproc = sysfunc("deferproc");
deferreturn = sysfunc("deferreturn");
naclnop = sysfunc("naclnop");
panicindex = sysfunc("panicindex");
panicslice = sysfunc("panicslice");
throwreturn = sysfunc("throwreturn");
}
if(fn->nbody == nil)
return;
// set up domain for labels
labellist = L;
lno = setlineno(fn);
curfn = fn;
dowidth(curfn->type);
if(curfn->type->outnamed) {
// add clearing of the output parameters
t = structfirst(&save, getoutarg(curfn->type));
while(t != T) {
if(t->nname != N)
curfn->nbody = concat(list1(nod(OAS, t->nname, N)), curfn->nbody);
t = structnext(&save);
}
}
hasdefer = 0;
walk(curfn);
if(nerrors != 0 || isblank(curfn->nname))
goto ret;
allocparams();
continpc = P;
breakpc = P;
pl = newplist();
pl->name = curfn->nname;
nodconst(&nod1, types[TINT32], 0);
ptxt = gins(ATEXT, curfn->nname, &nod1);
afunclit(&ptxt->from);
ginit();
genlist(curfn->enter);
pret = nil;
if(hasdefer || curfn->exit) {
Prog *p1;
p1 = gjmp(nil);
pret = gjmp(nil);
patch(p1, pc);
}
genlist(curfn->nbody);
gclean();
checklabels();
if(nerrors != 0)
goto ret;
if(curfn->type->outtuple != 0)
ginscall(throwreturn, 0);
if(pret)
patch(pret, pc);
ginit();
if(curfn->exit)
genlist(curfn->exit);
gclean();
if(nerrors != 0)
goto ret;
if(hasdefer) {
// On Native client, insert call to no-op function
// to force alignment immediately before call to deferreturn,
// so that when jmpdefer subtracts 5 from the second CALL's
// return address and then the return masks off the low bits,
// we'll back up to the NOPs immediately after the dummy CALL.
if(strcmp(getgoos(), "nacl") == 0)
ginscall(naclnop, 0);
ginscall(deferreturn, 0);
}
pc->as = ARET; // overwrite AEND
pc->lineno = lineno;
if(!debug['N'] || debug['R'] || debug['P']) {
regopt(ptxt);
}
// fill in argument size
ptxt->to.offset2 = rnd(curfn->type->argwid, maxround);
// fill in final stack size
if(stksize > maxstksize)
maxstksize = stksize;
ptxt->to.offset = rnd(maxstksize+maxarg, maxround);
maxstksize = 0;
if(debug['f'])
frame(0);
ret:
lineno = lno;
}
void
clearfat(Node *nl)
{
uint32 w, c, q;
Node n1;
/* clear a fat object */
if(debug['g'])
dump("\nclearfat", nl);
w = nl->type->width;
c = w % 4; // bytes
q = w / 4; // quads
gconreg(AMOVL, 0, D_AX);
nodreg(&n1, types[tptr], D_DI);
agen(nl, &n1);
if(q >= 4) {
gconreg(AMOVL, q, D_CX);
gins(AREP, N, N); // repeat
gins(ASTOSL, N, N); // STOL AL,*(DI)+
} else
while(q > 0) {
gins(ASTOSL, N, N); // STOL AL,*(DI)+
q--;
}
if(c >= 4) {
gconreg(AMOVL, c, D_CX);
gins(AREP, N, N); // repeat
gins(ASTOSB, N, N); // STOB AL,*(DI)+
} else
while(c > 0) {
gins(ASTOSB, N, N); // STOB AL,*(DI)+
c--;
}
}
/*
* generate:
* call f
* proc=0 normal call
* proc=1 goroutine run in new proc
* proc=2 defer call save away stack
*/
void
ginscall(Node *f, int proc)
{
Prog *p;
Node reg, con;
switch(proc) {
default:
fatal("ginscall: bad proc %d", proc);
break;
case 0: // normal call
p = gins(ACALL, N, f);
afunclit(&p->to);
break;
case 1: // call in new proc (go)
case 2: // deferred call (defer)
nodreg(&reg, types[TINT32], D_CX);
gins(APUSHL, f, N);
nodconst(&con, types[TINT32], argsize(f->type));
gins(APUSHL, &con, N);
if(proc == 1)
ginscall(newproc, 0);
else
ginscall(deferproc, 0);
gins(APOPL, N, &reg);
gins(APOPL, N, &reg);
if(proc == 2) {
nodreg(&reg, types[TINT64], D_AX);
gins(ATESTL, &reg, &reg);
patch(gbranch(AJNE, T), pret);
}
break;
}
}
/*
* n is call to interface method.
* generate res = n.
*/
void
cgen_callinter(Node *n, Node *res, int proc)
{
Node *i, *f;
Node tmpi, nodo, nodr, nodsp;
i = n->left;
if(i->op != ODOTINTER)
fatal("cgen_callinter: not ODOTINTER %O", i->op);
f = i->right; // field
if(f->op != ONAME)
fatal("cgen_callinter: not ONAME %O", f->op);
i = i->left; // interface
if(!i->addable) {
tempname(&tmpi, i->type);
cgen(i, &tmpi);
i = &tmpi;
}
genlist(n->list); // assign the args
// Can regalloc now; i is known to be addable,
// so the agen will be easy.
regalloc(&nodr, types[tptr], res);
regalloc(&nodo, types[tptr], &nodr);
nodo.op = OINDREG;
agen(i, &nodr); // REG = &inter
nodindreg(&nodsp, types[tptr], D_SP);
nodo.xoffset += widthptr;
cgen(&nodo, &nodsp); // 0(SP) = 8(REG) -- i.s
nodo.xoffset -= widthptr;
cgen(&nodo, &nodr); // REG = 0(REG) -- i.m
if(n->left->xoffset == BADWIDTH)
fatal("cgen_callinter: badwidth");
nodo.xoffset = n->left->xoffset + 3*widthptr + 8;
cgen(&nodo, &nodr); // REG = 32+offset(REG) -- i.m->fun[f]
// BOTCH nodr.type = fntype;
nodr.type = n->left->type;
ginscall(&nodr, proc);
regfree(&nodr);
regfree(&nodo);
setmaxarg(n->left->type);
}
/*
* generate function call;
* proc=0 normal call
* proc=1 goroutine run in new proc
* proc=2 defer call save away stack
*/
void
cgen_call(Node *n, int proc)
{
Type *t;
Node nod, afun;
if(n == N)
return;
if(n->left->ullman >= UINF) {
// if name involves a fn call
// precompute the address of the fn
tempname(&afun, types[tptr]);
cgen(n->left, &afun);
}
genlist(n->list); // assign the args
t = n->left->type;
setmaxarg(t);
// call tempname pointer
if(n->left->ullman >= UINF) {
regalloc(&nod, types[tptr], N);
cgen_as(&nod, &afun);
nod.type = t;
ginscall(&nod, proc);
regfree(&nod);
return;
}
// call pointer
if(n->left->op != ONAME || n->left->class != PFUNC) {
regalloc(&nod, types[tptr], N);
cgen_as(&nod, n->left);
nod.type = t;
ginscall(&nod, proc);
regfree(&nod);
return;
}
// call direct
n->left->method = 1;
ginscall(n->left, proc);
}
/*
* call to n has already been generated.
* generate:
* res = return value from call.
*/
void
cgen_callret(Node *n, Node *res)
{
Node nod;
Type *fp, *t;
Iter flist;
t = n->left->type;
if(t->etype == TPTR32 || t->etype == TPTR64)
t = t->type;
fp = structfirst(&flist, getoutarg(t));
if(fp == T)
fatal("cgen_callret: nil");
memset(&nod, 0, sizeof(nod));
nod.op = OINDREG;
nod.val.u.reg = D_SP;
nod.addable = 1;
nod.xoffset = fp->width;
nod.type = fp->type;
cgen_as(res, &nod);
}
/*
* call to n has already been generated.
* generate:
* res = &return value from call.
*/
void
cgen_aret(Node *n, Node *res)
{
Node nod1, nod2;
Type *fp, *t;
Iter flist;
t = n->left->type;
if(isptr[t->etype])
t = t->type;
fp = structfirst(&flist, getoutarg(t));
if(fp == T)
fatal("cgen_aret: nil");
memset(&nod1, 0, sizeof(nod1));
nod1.op = OINDREG;
nod1.val.u.reg = D_SP;
nod1.addable = 1;
nod1.xoffset = fp->width;
nod1.type = fp->type;
if(res->op != OREGISTER) {
regalloc(&nod2, types[tptr], res);
gins(ALEAL, &nod1, &nod2);
gins(AMOVL, &nod2, res);
regfree(&nod2);
} else
gins(ALEAL, &nod1, res);
}
/*
* generate return.
* n->left is assignments to return values.
*/
void
cgen_ret(Node *n)
{
genlist(n->list); // copy out args
if(pret)
gjmp(pret);
else
gins(ARET, N, N);
}
/*
* generate += *= etc.
*/
void
cgen_asop(Node *n)
{
Node n1, n2, n3, n4;
Node *nl, *nr;
Prog *p1;
Addr addr;
int a;
nl = n->left;
nr = n->right;
if(nr->ullman >= UINF && nl->ullman >= UINF) {
tempname(&n1, nr->type);
cgen(nr, &n1);
n2 = *n;
n2.right = &n1;
cgen_asop(&n2);
goto ret;
}
if(!isint[nl->type->etype])
goto hard;
if(!isint[nr->type->etype])
goto hard;
if(is64(nl->type) || is64(nr->type))
goto hard;
switch(n->etype) {
case OADD:
if(smallintconst(nr))
if(mpgetfix(nr->val.u.xval) == 1) {
a = optoas(OINC, nl->type);
if(nl->addable) {
gins(a, N, nl);
goto ret;
}
if(sudoaddable(a, nl, &addr)) {
p1 = gins(a, N, N);
p1->to = addr;
sudoclean();
goto ret;
}
}
break;
case OSUB:
if(smallintconst(nr))
if(mpgetfix(nr->val.u.xval) == 1) {
a = optoas(ODEC, nl->type);
if(nl->addable) {
gins(a, N, nl);
goto ret;
}
if(sudoaddable(a, nl, &addr)) {
p1 = gins(a, N, N);
p1->to = addr;
sudoclean();
goto ret;
}
}
break;
}
switch(n->etype) {
case OADD:
case OSUB:
case OXOR:
case OAND:
case OOR:
a = optoas(n->etype, nl->type);
if(nl->addable) {
if(smallintconst(nr)) {
gins(a, nr, nl);
goto ret;
}
regalloc(&n2, nr->type, N);
cgen(nr, &n2);
gins(a, &n2, nl);
regfree(&n2);
goto ret;
}
if(nr->ullman < UINF)
if(sudoaddable(a, nl, &addr)) {
if(smallintconst(nr)) {
p1 = gins(a, nr, N);
p1->to = addr;
sudoclean();
goto ret;
}
regalloc(&n2, nr->type, N);
cgen(nr, &n2);
p1 = gins(a, &n2, N);
p1->to = addr;
regfree(&n2);
sudoclean();
goto ret;
}
}
hard:
n2.op = 0;
n1.op = 0;
if(nr->ullman >= nl->ullman || nl->addable) {
mgen(nr, &n2, N);
nr = &n2;
nr = &n2;
} else {
tempname(&n2, nr->type);
cgen(nr, &n2);
nr = &n2;
}
if(!nl->addable) {
igen(nl, &n1, N);
nl = &n1;
}
n3 = *n;
n3.left = nl;
n3.right = nr;
n3.op = n->etype;
mgen(&n3, &n4, N);
gmove(&n4, nl);
if(n1.op)
regfree(&n1);
mfree(&n2);
mfree(&n4);
ret:
;
}
int
samereg(Node *a, Node *b)
{
if(a->op != OREGISTER)
return 0;
if(b->op != OREGISTER)
return 0;
if(a->val.u.reg != b->val.u.reg)
return 0;
return 1;
}
/*
* generate division.
* caller must set:
* ax = allocated AX register
* dx = allocated DX register
* generates one of:
* res = nl / nr
* res = nl % nr
* according to op.
*/
void
dodiv(int op, Type *t, Node *nl, Node *nr, Node *res, Node *ax, Node *dx)
{
Node n1, t1, t2, nz;
tempname(&t1, nl->type);
tempname(&t2, nr->type);
cgen(nl, &t1);
cgen(nr, &t2);
if(!samereg(ax, res) && !samereg(dx, res))
regalloc(&n1, t, res);
else
regalloc(&n1, t, N);
gmove(&t2, &n1);
gmove(&t1, ax);
if(!issigned[t->etype]) {
nodconst(&nz, t, 0);
gmove(&nz, dx);
} else
gins(optoas(OEXTEND, t), N, N);
gins(optoas(op, t), &n1, N);
regfree(&n1);
if(op == ODIV)
gmove(ax, res);
else
gmove(dx, res);
}
static void
savex(int dr, Node *x, Node *oldx, Node *res, Type *t)
{
int r;
r = reg[dr];
nodreg(x, types[TINT32], dr);
// save current ax and dx if they are live
// and not the destination
memset(oldx, 0, sizeof *oldx);
if(r > 0 && !samereg(x, res)) {
tempname(oldx, types[TINT32]);
gmove(x, oldx);
}
regalloc(x, t, x);
}
static void
restx(Node *x, Node *oldx)
{
regfree(x);
if(oldx->op != 0) {
x->type = types[TINT32];
gmove(oldx, x);
}
}
/*
* generate division according to op, one of:
* res = nl / nr
* res = nl % nr
*/
void
cgen_div(int op, Node *nl, Node *nr, Node *res)
{
Node ax, dx, oldax, olddx;
int rax, rdx;
Type *t;
rax = reg[D_AX];
rdx = reg[D_DX];
if(is64(nl->type))
fatal("cgen_div %T", nl->type);
t = nl->type;
if(t->width == 1)
t = types[t->etype+2]; // int8 -> int16, uint8 -> uint16
savex(D_AX, &ax, &oldax, res, t);
savex(D_DX, &dx, &olddx, res, t);
dodiv(op, t, nl, nr, res, &ax, &dx);
restx(&dx, &olddx);
restx(&ax, &oldax);
}
/*
* generate shift according to op, one of:
* res = nl << nr
* res = nl >> nr
*/
void
cgen_shift(int op, Node *nl, Node *nr, Node *res)
{
Node n1, n2, cx, oldcx;
int a, w;
Prog *p1;
uvlong sc;
if(nl->type->width > 4)
fatal("cgen_shift %T", nl->type);
w = nl->type->width * 8;
a = optoas(op, nl->type);
if(nr->op == OLITERAL) {
tempname(&n2, nl->type);
cgen(nl, &n2);
regalloc(&n1, nl->type, res);
gmove(&n2, &n1);
sc = mpgetfix(nr->val.u.xval);
if(sc >= nl->type->width*8) {
// large shift gets 2 shifts by width
gins(a, ncon(w-1), &n1);
gins(a, ncon(w-1), &n1);
} else
gins(a, nr, &n1);
gmove(&n1, res);
regfree(&n1);
return;
}
memset(&oldcx, 0, sizeof oldcx);
nodreg(&cx, types[TUINT32], D_CX);
if(reg[D_CX] > 1 && !samereg(&cx, res)) {
tempname(&oldcx, types[TUINT32]);
gmove(&cx, &oldcx);
}
nodreg(&n1, types[TUINT32], D_CX);
regalloc(&n1, nr->type, &n1); // to hold the shift type in CX
if(samereg(&cx, res))
regalloc(&n2, nl->type, N);
else
regalloc(&n2, nl->type, res);
if(nl->ullman >= nr->ullman) {
cgen(nl, &n2);
cgen(nr, &n1);
} else {
cgen(nr, &n1);
cgen(nl, &n2);
}
// test and fix up large shifts
gins(optoas(OCMP, nr->type), &n1, ncon(w));
p1 = gbranch(optoas(OLT, types[TUINT32]), T);
if(op == ORSH && issigned[nl->type->etype]) {
gins(a, ncon(w-1), &n2);
} else {
gmove(ncon(0), &n2);
}
patch(p1, pc);
gins(a, &n1, &n2);
if(oldcx.op != 0)
gmove(&oldcx, &cx);
gmove(&n2, res);
regfree(&n1);
regfree(&n2);
}
/*
* generate byte multiply:
* res = nl * nr
* no byte multiply instruction so have to do
* 16-bit multiply and take bottom half.
*/
void
cgen_bmul(int op, Node *nl, Node *nr, Node *res)
{
Node n1b, n2b, n1w, n2w;
Type *t;
int a;
if(nl->ullman >= nr->ullman) {
regalloc(&n1b, nl->type, res);
cgen(nl, &n1b);
regalloc(&n2b, nr->type, N);
cgen(nr, &n2b);
} else {
regalloc(&n2b, nr->type, N);
cgen(nr, &n2b);
regalloc(&n1b, nl->type, res);
cgen(nl, &n1b);
}
// copy from byte to short registers
t = types[TUINT16];
if(issigned[nl->type->etype])
t = types[TINT16];
regalloc(&n2w, t, &n2b);
cgen(&n2b, &n2w);
regalloc(&n1w, t, &n1b);
cgen(&n1b, &n1w);
a = optoas(op, t);
gins(a, &n2w, &n1w);
cgen(&n1w, &n1b);
cgen(&n1b, res);
regfree(&n1w);
regfree(&n2w);
regfree(&n1b);
regfree(&n2b);
}
static int
regcmp(const void *va, const void *vb)
{
Node *ra, *rb;
ra = (Node*)va;
rb = (Node*)vb;
return ra->local - rb->local;
}
static Prog* throwpc;
void
getargs(NodeList *nn, Node *reg, int n)
{
NodeList *l;
int i;
throwpc = nil;
l = nn;
for(i=0; i<n; i++) {
if(!smallintconst(l->n->right) && !isslice(l->n->right->type)) {
if(i < 3) // AX CX DX
nodreg(reg+i, l->n->right->type, D_AX+i);
else
reg[i].op = OXXX;
regalloc(reg+i, l->n->right->type, reg+i);
cgen(l->n->right, reg+i);
} else
reg[i] = *l->n->right;
if(reg[i].local != 0)
yyerror("local used");
reg[i].local = l->n->left->xoffset;
l = l->next;
}
qsort((void*)reg, n, sizeof(*reg), regcmp);
for(i=0; i<n; i++)
reg[i].local = 0;
}
void
cmpandthrow(Node *nl, Node *nr)
{
vlong cl, cr;
Prog *p1;
int op;
Node *c;
op = OLE;
if(smallintconst(nl)) {
cl = mpgetfix(nl->val.u.xval);
if(cl == 0)
return;
if(smallintconst(nr)) {
cr = mpgetfix(nr->val.u.xval);
if(cl > cr) {
if(throwpc == nil) {
throwpc = pc;
ginscall(panicslice, 0);
} else
patch(gbranch(AJMP, T), throwpc);
}
return;
}
// put the constant on the right
op = brrev(op);
c = nl;
nl = nr;
nr = c;
}
gins(optoas(OCMP, types[TUINT32]), nl, nr);
if(throwpc == nil) {
p1 = gbranch(optoas(op, types[TUINT32]), T);
throwpc = pc;
ginscall(panicslice, 0);
patch(p1, pc);
} else {
op = brcom(op);
p1 = gbranch(optoas(op, types[TUINT32]), T);
patch(p1, throwpc);
}
}
int
sleasy(Node *n)
{
if(n->op != ONAME)
return 0;
if(!n->addable)
return 0;
return 1;
}
// generate inline code for
// slicearray
// sliceslice
// arraytoslice
int
cgen_inline(Node *n, Node *res)
{
Node nodes[5];
Node n1, n2, nres, ntemp;
vlong v;
int i, narg;
if(n->op != OCALLFUNC)
goto no;
if(!n->left->addable)
goto no;
if(n->left->sym->pkg != runtimepkg)
goto no;
if(strcmp(n->left->sym->name, "slicearray") == 0)
goto slicearray;
if(strcmp(n->left->sym->name, "sliceslice") == 0) {
narg = 4;
goto sliceslice;
}
if(strcmp(n->left->sym->name, "sliceslice1") == 0) {
narg = 3;
goto sliceslice;
}
goto no;
slicearray:
if(!sleasy(res))
goto no;
getargs(n->list, nodes, 5);
// if(hb[3] > nel[1]) goto throw
cmpandthrow(&nodes[3], &nodes[1]);
// if(lb[2] > hb[3]) goto throw
cmpandthrow(&nodes[2], &nodes[3]);
// len = hb[3] - lb[2] (destroys hb)
n2 = *res;
n2.xoffset += Array_nel;
if(smallintconst(&nodes[3]) && smallintconst(&nodes[2])) {
v = mpgetfix(nodes[3].val.u.xval) -
mpgetfix(nodes[2].val.u.xval);
nodconst(&n1, types[TUINT32], v);
gins(optoas(OAS, types[TUINT32]), &n1, &n2);
} else {
regalloc(&n1, types[TUINT32], &nodes[3]);
gmove(&nodes[3], &n1);
if(!smallintconst(&nodes[2]) || mpgetfix(nodes[2].val.u.xval) != 0)
gins(optoas(OSUB, types[TUINT32]), &nodes[2], &n1);
gins(optoas(OAS, types[TUINT32]), &n1, &n2);
regfree(&n1);
}
// cap = nel[1] - lb[2] (destroys nel)
n2 = *res;
n2.xoffset += Array_cap;
if(smallintconst(&nodes[1]) && smallintconst(&nodes[2])) {
v = mpgetfix(nodes[1].val.u.xval) -
mpgetfix(nodes[2].val.u.xval);
nodconst(&n1, types[TUINT32], v);
gins(optoas(OAS, types[TUINT32]), &n1, &n2);
} else {
regalloc(&n1, types[TUINT32], &nodes[1]);
gmove(&nodes[1], &n1);
if(!smallintconst(&nodes[2]) || mpgetfix(nodes[2].val.u.xval) != 0)
gins(optoas(OSUB, types[TUINT32]), &nodes[2], &n1);
gins(optoas(OAS, types[TUINT32]), &n1, &n2);
regfree(&n1);
}
// if slice could be too big, dereference to
// catch nil array pointer.
if(nodes[0].op == OREGISTER && nodes[0].type->type->width >= unmappedzero) {
n2 = nodes[0];
n2.xoffset = 0;
n2.op = OINDREG;
n2.type = types[TUINT8];
gins(ATESTB, nodintconst(0), &n2);
}
// ary = old[0] + (lb[2] * width[4]) (destroys old)
n2 = *res;
n2.xoffset += Array_array;
if(smallintconst(&nodes[2]) && smallintconst(&nodes[4])) {
v = mpgetfix(nodes[2].val.u.xval) *
mpgetfix(nodes[4].val.u.xval);
if(v != 0) {
nodconst(&n1, types[tptr], v);
gins(optoas(OADD, types[tptr]), &n1, &nodes[0]);
}
} else {
regalloc(&n1, types[tptr], &nodes[2]);
gmove(&nodes[2], &n1);
if(!smallintconst(&nodes[4]) || mpgetfix(nodes[4].val.u.xval) != 1)
gins(optoas(OMUL, types[tptr]), &nodes[4], &n1);
gins(optoas(OADD, types[tptr]), &n1, &nodes[0]);
regfree(&n1);
}
gins(optoas(OAS, types[tptr]), &nodes[0], &n2);
for(i=0; i<5; i++) {
if(nodes[i].op == OREGISTER)
regfree(&nodes[i]);
}
return 1;
sliceslice:
ntemp.op = OXXX;
if(!sleasy(n->list->n->right)) {
Node *n0;
n0 = n->list->n->right;
tempname(&ntemp, res->type);
cgen(n0, &ntemp);
n->list->n->right = &ntemp;
getargs(n->list, nodes, narg);
n->list->n->right = n0;
} else
getargs(n->list, nodes, narg);
nres = *res; // result
if(!sleasy(res)) {
if(ntemp.op == OXXX)
tempname(&ntemp, res->type);
nres = ntemp;
}
if(narg == 3) { // old[lb:]
// move width to where it would be for old[lb:hb]
nodes[3] = nodes[2];
nodes[2].op = OXXX;
// if(lb[1] > old.nel[0]) goto throw;
n2 = nodes[0];
n2.xoffset += Array_nel;
cmpandthrow(&nodes[1], &n2);
// ret.nel = old.nel[0]-lb[1];
n2 = nodes[0];
n2.xoffset += Array_nel;
regalloc(&n1, types[TUINT32], N);
gins(optoas(OAS, types[TUINT32]), &n2, &n1);
if(!smallintconst(&nodes[1]) || mpgetfix(nodes[1].val.u.xval) != 0)
gins(optoas(OSUB, types[TUINT32]), &nodes[1], &n1);
n2 = nres;
n2.xoffset += Array_nel;
gins(optoas(OAS, types[TUINT32]), &n1, &n2);
regfree(&n1);
} else { // old[lb:hb]
// if(hb[2] > old.cap[0]) goto throw;
n2 = nodes[0];
n2.xoffset += Array_cap;
cmpandthrow(&nodes[2], &n2);
// if(lb[1] > hb[2]) goto throw;
cmpandthrow(&nodes[1], &nodes[2]);
// ret.len = hb[2]-lb[1]; (destroys hb[2])
n2 = nres;
n2.xoffset += Array_nel;
if(smallintconst(&nodes[2]) && smallintconst(&nodes[1])) {
v = mpgetfix(nodes[2].val.u.xval) -
mpgetfix(nodes[1].val.u.xval);
nodconst(&n1, types[TUINT32], v);
gins(optoas(OAS, types[TUINT32]), &n1, &n2);
} else {
regalloc(&n1, types[TUINT32], &nodes[2]);
gmove(&nodes[2], &n1);
if(!smallintconst(&nodes[1]) || mpgetfix(nodes[1].val.u.xval) != 0)
gins(optoas(OSUB, types[TUINT32]), &nodes[1], &n1);
gins(optoas(OAS, types[TUINT32]), &n1, &n2);
regfree(&n1);
}
}
// ret.cap = old.cap[0]-lb[1]; (uses hb[2])
n2 = nodes[0];
n2.xoffset += Array_cap;
regalloc(&n1, types[TUINT32], &nodes[2]);
gins(optoas(OAS, types[TUINT32]), &n2, &n1);
if(!smallintconst(&nodes[1]) || mpgetfix(nodes[1].val.u.xval) != 0)
gins(optoas(OSUB, types[TUINT32]), &nodes[1], &n1);
n2 = nres;
n2.xoffset += Array_cap;
gins(optoas(OAS, types[TUINT32]), &n1, &n2);
regfree(&n1);
// ret.array = old.array[0]+lb[1]*width[3]; (uses lb[1])
n2 = nodes[0];
n2.xoffset += Array_array;
regalloc(&n1, types[tptr], &nodes[1]);
if(smallintconst(&nodes[1]) && smallintconst(&nodes[3])) {
gins(optoas(OAS, types[tptr]), &n2, &n1);
v = mpgetfix(nodes[1].val.u.xval) *
mpgetfix(nodes[3].val.u.xval);
if(v != 0) {
nodconst(&n2, types[tptr], v);
gins(optoas(OADD, types[tptr]), &n2, &n1);
}
} else {
gmove(&nodes[1], &n1);
if(!smallintconst(&nodes[3]) || mpgetfix(nodes[3].val.u.xval) != 1)
gins(optoas(OMUL, types[tptr]), &nodes[3], &n1);
gins(optoas(OADD, types[tptr]), &n2, &n1);
}
n2 = nres;
n2.xoffset += Array_array;
gins(optoas(OAS, types[tptr]), &n1, &n2);
regfree(&n1);
for(i=0; i<4; i++) {
if(nodes[i].op == OREGISTER)
regfree(&nodes[i]);
}
if(!sleasy(res)) {
cgen(&nres, res);
}
return 1;
no:
return 0;
}