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267 lines
11 KiB
ObjectPascal
267 lines
11 KiB
ObjectPascal
{
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Copyright (c) 2002-2014 by Florian Klaempfl
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Generate i8086 assembler for load nodes
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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****************************************************************************
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}
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unit n8086ld;
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{$i fpcdefs.inc}
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interface
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uses
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globtype,
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symsym,symtype,
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node,ncgld,nx86ld,aasmbase;
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type
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{ ti8086loadnode }
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ti8086loadnode = class(tx86loadnode)
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protected
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procedure generate_nested_access(vs: tsym); override;
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procedure generate_absaddr_access(vs: tabsolutevarsym); override;
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procedure generate_threadvar_access(gvs: tstaticvarsym); override;
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public
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procedure pass_generate_code;override;
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end;
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implementation
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uses
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globals,verbose,aasmdata,defutil,
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symconst,symdef,symtable,symcpu,
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nld,
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cgbase,cgobj,cgutils,
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hlcgobj,
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cpubase,cpuinfo,
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parabase,paramgr;
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{*****************************************************************************
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TI8086LOADNODE
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*****************************************************************************}
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procedure ti8086loadnode.generate_nested_access(vs: tsym);
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begin
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inherited;
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{ the parentfp pointer is always a near pointer (this is turbo pascal
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compatible) regardless of memory model, so we need to set the segment
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manually.
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todo: once the far data memory models are fully implemented, the
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parentfp type should be changed to a near 'ss' pointer in all memory
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models and then this code can be removed. But this can only happen
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after:
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1) all calls to a_loadaddr_ref_reg go through the high level code
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generator
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2) a_loadaddr_ref_reg in the low level code generator stops using
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the presence of a segment in the source reference to determine the
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destination reg size
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3) make_simple_ref is updated to remove unnecessary segment prefixes
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4) hlcg.reference_reset_base is updated to set the segment on near_ss
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pointers }
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if (left.nodetype=loadparentfpn) and
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(current_settings.x86memorymodel in x86_far_data_models) then
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location.reference.segment:=NR_SS;
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end;
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procedure ti8086loadnode.generate_absaddr_access(vs: tabsolutevarsym);
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begin
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if tcpuabsolutevarsym(symtableentry).absseg then
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begin
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location.reference.segment:=cg.getintregister(current_asmdata.CurrAsmList,OS_16);
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cg.a_load_const_reg(current_asmdata.CurrAsmList,OS_16,aint(tcpuabsolutevarsym(symtableentry).addrsegment),location.reference.segment);
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end;
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inherited;
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end;
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procedure ti8086loadnode.generate_threadvar_access(gvs: tstaticvarsym);
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var
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segref: treference;
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segreg: TRegister;
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newsize: TCgSize;
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norelocatelab: TAsmLabel;
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endrelocatelab: TAsmLabel;
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pvd: tdef;
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paraloc1 : tcgpara;
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hregister: TRegister;
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href: treference;
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begin
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if current_settings.x86memorymodel=mm_huge then
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begin
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if (cs_compilesystem in current_settings.moduleswitches) then
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begin
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inherited generate_threadvar_access(gvs);
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exit;
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end;
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{ we don't know the size of all arrays }
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newsize:=def_cgsize(resultdef);
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{ alignment is overridden per case below }
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location_reset_ref(location,LOC_REFERENCE,newsize,resultdef.alignment,[]);
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{
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Thread var loading is optimized to first check if
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a relocate function is available. When the function
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is available it is called to retrieve the address.
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Otherwise the address is loaded with the symbol
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The code needs to be in the order to first handle the
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call and then the address load to be sure that the
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register that is used for returning is the same (PFV)
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}
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current_asmdata.getjumplabel(norelocatelab);
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current_asmdata.getjumplabel(endrelocatelab);
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{ make sure hregister can't allocate the register necessary for the parameter }
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pvd:=search_system_type('TRELOCATETHREADVARHANDLER').typedef;
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if pvd.typ<>procvardef then
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internalerror(2012120902);
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paraloc1.init;
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paramanager.getcgtempparaloc(current_asmdata.CurrAsmList,tprocvardef(pvd),1,paraloc1);
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hregister:=hlcg.getaddressregister(current_asmdata.CurrAsmList,pvd);
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segreg:=cg.getintregister(current_asmdata.CurrAsmList,OS_16);
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reference_reset_symbol(segref,current_asmdata.RefAsmSymbol('FPC_THREADVAR_RELOCATE',AT_DATA),0,pvd.alignment,[]);
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segref.refaddr:=addr_seg;
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cg.a_load_ref_reg(current_asmdata.CurrAsmList,OS_16,OS_16,segref,segreg);
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reference_reset_symbol(href,current_asmdata.RefAsmSymbol('FPC_THREADVAR_RELOCATE',AT_DATA),0,pvd.alignment,[]);
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href.segment:=segreg;
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hlcg.a_load_ref_reg(current_asmdata.CurrAsmList,pvd,pvd,href,hregister);
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hlcg.a_cmp_const_reg_label(current_asmdata.CurrAsmList,pvd,OC_EQ,0,hregister,norelocatelab);
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{ don't save the allocated register else the result will be destroyed later }
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if not(vo_is_weak_external in gvs.varoptions) then
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reference_reset_symbol(href,current_asmdata.RefAsmSymbol(gvs.mangledname,AT_DATA),0,2,[])
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else
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reference_reset_symbol(href,current_asmdata.WeakRefAsmSymbol(gvs.mangledname,AT_DATA),0,2,[]);
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cg.a_load_ref_cgpara(current_asmdata.CurrAsmList,OS_16,href,paraloc1);
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paramanager.freecgpara(current_asmdata.CurrAsmList,paraloc1);
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paraloc1.done;
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cg.allocallcpuregisters(current_asmdata.CurrAsmList);
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cg.a_call_reg(current_asmdata.CurrAsmList,hregister);
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cg.deallocallcpuregisters(current_asmdata.CurrAsmList);
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cg.getcpuregister(current_asmdata.CurrAsmList,NR_FUNCTION_RESULT_REG);
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cg.ungetcpuregister(current_asmdata.CurrAsmList,NR_FUNCTION_RESULT_REG);
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hregister:=hlcg.getaddressregister(current_asmdata.CurrAsmList,voidpointertype);
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cg.a_load_reg_reg(current_asmdata.CurrAsmList,OS_INT,OS_ADDR,NR_FUNCTION_RESULT_REG,hregister);
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cg.a_jmp_always(current_asmdata.CurrAsmList,endrelocatelab);
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cg.a_label(current_asmdata.CurrAsmList,norelocatelab);
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{ no relocation needed, load the address of the variable only, the
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layout of a threadvar is (4 bytes pointer):
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0 - Threadvar index
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4 - Threadvar value in single threading }
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if not(vo_is_weak_external in gvs.varoptions) then
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reference_reset_symbol(href,current_asmdata.RefAsmSymbol(gvs.mangledname,AT_DATA),sizeof(pint),2,[])
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else
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reference_reset_symbol(href,current_asmdata.WeakRefAsmSymbol(gvs.mangledname,AT_DATA),sizeof(pint),2,[]);
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hlcg.a_loadaddr_ref_reg(current_asmdata.CurrAsmList,resultdef,voidpointertype,href,hregister);
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cg.a_label(current_asmdata.CurrAsmList,endrelocatelab);
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hlcg.reference_reset_base(location.reference,voidpointertype,hregister,0,ctempposinvalid,location.reference.alignment,[]);
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end
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else
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inherited generate_threadvar_access(gvs);
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end;
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procedure ti8086loadnode.pass_generate_code;
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var
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gvs: tstaticvarsym;
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segref: treference;
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refsym: TAsmSymbol;
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segreg: TRegister;
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newsize: TCgSize;
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begin
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case symtableentry.typ of
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staticvarsym:
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begin
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gvs:=tstaticvarsym(symtableentry);
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if (vo_is_dll_var in gvs.varoptions) then
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{ DLL variable }
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begin
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inherited pass_generate_code;
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exit;
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end
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{ Thread variable }
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else if (vo_is_thread_var in gvs.varoptions) then
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begin
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{ this will be handled in ti8086loadnode.generate_threadvar_access }
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inherited pass_generate_code;
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exit;
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end
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{ Normal (or external) variable }
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else
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begin
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if ((current_settings.x86memorymodel<>mm_huge) and not (vo_is_far in gvs.varoptions)) or
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(not (vo_is_external in gvs.varoptions) and gvs.Owner.iscurrentunit) then
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begin
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inherited pass_generate_code;
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if location.loc in [LOC_REFERENCE,LOC_CREFERENCE] then
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location.reference.segment:=NR_DS;
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exit;
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end;
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{ we don't know the size of all arrays }
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newsize:=def_cgsize(resultdef);
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{ alignment is overridden per case below }
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location_reset_ref(location,LOC_REFERENCE,newsize,resultdef.alignment,[]);
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if gvs.localloc.loc=LOC_INVALID then
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begin
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if not(vo_is_weak_external in gvs.varoptions) then
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refsym:=current_asmdata.RefAsmSymbol(gvs.mangledname,AT_DATA)
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else
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refsym:=current_asmdata.WeakRefAsmSymbol(gvs.mangledname,AT_DATA);
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segreg:=cg.getintregister(current_asmdata.CurrAsmList,OS_16);
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reference_reset_symbol(segref,refsym,0,0,[]);
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segref.refaddr:=addr_seg;
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cg.a_load_ref_reg(current_asmdata.CurrAsmList,OS_16,OS_16,segref,segreg);
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reference_reset_symbol(location.reference,refsym,0,location.reference.alignment,[]);
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location.reference.segment:=segreg;
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end
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else
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location:=gvs.localloc;
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end;
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{ make const a LOC_CREFERENCE }
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if (gvs.varspez=vs_const) and
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(location.loc=LOC_REFERENCE) then
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location.loc:=LOC_CREFERENCE;
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end;
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procsym:
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begin
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inherited pass_generate_code;
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if current_settings.x86memorymodel in x86_near_code_models then
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begin
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if (location.loc=LOC_REFERENCE) or (location.loc=LOC_CREFERENCE) then
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location.reference.segment:=NR_CS;
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end;
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end;
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else
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inherited pass_generate_code;
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end;
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end;
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begin
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cloadnode:=ti8086loadnode;
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end.
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