{
Copyright (c) 1998-2002 by Florian Klaempfl
Generate i386 assembler for in set/case nodes
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
****************************************************************************
}
unit n386set;
{$i fpcdefs.inc}
interface
uses
globtype,
node,nset,pass_1,ncgset;
type
ti386casenode = class(tcgcasenode)
procedure optimizevalues(var max_linear_list:aint;var max_dist:aword);override;
function has_jumptable : boolean;override;
procedure genjumptable(hp : pcaselabel;min_,max_ : aint);override;
procedure genlinearlist(hp : pcaselabel);override;
end;
implementation
uses
systems,
verbose,globals,
symconst,symdef,defutil,
aasmbase,aasmtai,aasmdata,aasmcpu,
cgbase,pass_2,
ncon,
cpubase,cpuinfo,procinfo,
cga,cgutils,cgobj,ncgutil,
cgx86;
{*****************************************************************************
TI386CASENODE
*****************************************************************************}
procedure ti386casenode.optimizevalues(var max_linear_list:aint;var max_dist:aword);
begin
{ a jump table crashes the pipeline! }
if current_settings.optimizecputype=cpu_386 then
inc(max_linear_list,3)
else if current_settings.optimizecputype=cpu_Pentium then
inc(max_linear_list,6)
else if current_settings.optimizecputype in [cpu_Pentium2,cpu_Pentium3] then
inc(max_linear_list,9)
else if current_settings.optimizecputype=cpu_Pentium4 then
inc(max_linear_list,14);
end;
function ti386casenode.has_jumptable : boolean;
begin
has_jumptable:=true;
end;
procedure ti386casenode.genjumptable(hp : pcaselabel;min_,max_ : aint);
var
table : tasmlabel;
last : TConstExprInt;
indexreg : tregister;
href : treference;
procedure genitem(list:TAsmList;t : pcaselabel);
var
i : aint;
begin
if assigned(t^.less) then
genitem(list,t^.less);
{ fill possible hole }
for i:=last+1 to t^._low-1 do
list.concat(Tai_const.Create_sym(elselabel));
for i:=t^._low to t^._high do
list.concat(Tai_const.Create_sym(blocklabel(t^.blockid)));
last:=t^._high;
if assigned(t^.greater) then
genitem(list,t^.greater);
end;
begin
if not(jumptable_no_range) then
begin
{ case expr less than min_ => goto elselabel }
cg.a_cmp_const_reg_label(current_asmdata.CurrAsmList,opsize,jmp_lt,aint(min_),hregister,elselabel);
{ case expr greater than max_ => goto elselabel }
cg.a_cmp_const_reg_label(current_asmdata.CurrAsmList,opsize,jmp_gt,aint(max_),hregister,elselabel);
end;
current_asmdata.getjumplabel(table);
{ make it a 32bit register }
indexreg:=cg.makeregsize(current_asmdata.CurrAsmList,hregister,OS_INT);
cg.a_load_reg_reg(current_asmdata.CurrAsmList,opsize,OS_INT,hregister,indexreg);
{ create reference }
reference_reset_symbol(href,table,0);
href.offset:=(-aint(min_))*4;
href.index:=indexreg;
href.scalefactor:=4;
emit_ref(A_JMP,S_NO,href);
{ generate jump table }
new_section(current_procinfo.aktlocaldata,sec_data,current_procinfo.procdef.mangledname,sizeof(aint));
current_procinfo.aktlocaldata.concat(Tai_label.Create(table));
last:=min_;
genitem(current_procinfo.aktlocaldata,hp);
end;
procedure ti386casenode.genlinearlist(hp : pcaselabel);
var
first : boolean;
lastrange : boolean;
last : TConstExprInt;
cond_lt,cond_le : tresflags;
procedure genitem(t : pcaselabel);
begin
if assigned(t^.less) then
genitem(t^.less);
{ need we to test the first value }
if first and (t^._low>get_min_value(left.resultdef)) then
begin
cg.a_cmp_const_reg_label(current_asmdata.CurrAsmList,opsize,jmp_lt,aint(t^._low),hregister,elselabel);
end;
if t^._low=t^._high then
begin
if t^._low-last=0 then
cg.a_cmp_const_reg_label(current_asmdata.CurrAsmList, opsize, OC_EQ,0,hregister,blocklabel(t^.blockid))
else
begin
cg.a_op_const_reg(current_asmdata.CurrAsmList, OP_SUB, opsize, aint(t^._low-last), hregister);
cg.a_jmp_flags(current_asmdata.CurrAsmList,F_E,blocklabel(t^.blockid));
end;
last:=t^._low;
lastrange:=false;
end
else
begin
{ it begins with the smallest label, if the value }
{ is even smaller then jump immediately to the }
{ ELSE-label }
if first then
begin
{ have we to ajust the first value ? }
if (t^._low>get_min_value(left.resultdef)) then
cg.a_op_const_reg(current_asmdata.CurrAsmList, OP_SUB, opsize, aint(t^._low), hregister);
end
else
begin
{ if there is no unused label between the last and the }
{ present label then the lower limit can be checked }
{ immediately. else check the range in between: }
cg.a_op_const_reg(current_asmdata.CurrAsmList, OP_SUB, opsize, aint(t^._low-last), hregister);
{ no jump necessary here if the new range starts at }
{ at the value following the previous one }
if ((t^._low-last) <> 1) or
(not lastrange) then
cg.a_jmp_flags(current_asmdata.CurrAsmList,cond_lt,elselabel);
end;
{we need to use A_SUB, because A_DEC does not set the correct flags, therefor
using a_op_const_reg(OP_SUB) is not possible }
emit_const_reg(A_SUB,TCGSize2OpSize[opsize],aint(t^._high-t^._low),hregister);
cg.a_jmp_flags(current_asmdata.CurrAsmList,cond_le,blocklabel(t^.blockid));
last:=t^._high;
lastrange:=true;
end;
first:=false;
if assigned(t^.greater) then
genitem(t^.greater);
end;
begin
if with_sign then
begin
cond_lt:=F_L;
cond_le:=F_LE;
end
else
begin
cond_lt:=F_B;
cond_le:=F_BE;
end;
{ do we need to generate cmps? }
if (with_sign and (min_label<0)) then
genlinearcmplist(hp)
else
begin
last:=0;
lastrange:=false;
first:=true;
genitem(hp);
cg.a_jmp_always(current_asmdata.CurrAsmList,elselabel);
end;
end;
begin
ccasenode:=ti386casenode;
end.
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