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* a_load_subsetreg_reg will no longer generate an AND instruction if it isn't necessary

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J. Gareth "Curious Kit" Moreton 2022-10-19 03:08:24 +01:00 committed by FPK
parent 7e593750e8
commit 130c36c406
1 changed files with 30 additions and 7 deletions
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37
compiler/hlcgobj.pas
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@ -1328,6 +1328,24 @@ implementation
{$r-,q-}
procedure thlcgobj.a_load_subsetreg_reg(list: TAsmList; subsetsize, tosize: tdef; const sreg: tsubsetregister; destreg: tregister);
function GetRegBitSize: Integer;
begin
case getsubreg(sreg.subsetreg) of
R_SUBL, R_SUBH:
Result := 8;
R_SUBW:
Result := 16;
R_SUBD:
Result := 32;
R_SUBQ:
Result := 64;
else
{ So (stopbit < regsize) will always return True }
Result := High(Integer);
end;
end;
var
subsetregdef: torddef;
bitmask: aword;
@ -1352,13 +1370,18 @@ implementation
begin
a_op_const_reg_reg(list,OP_SHR,subsetregdef,sreg.startbit,sreg.subsetreg,tmpreg);
stopbit:=sreg.startbit+sreg.bitlen;
// on x86(64), 1 shl 32(64) = 1 instead of 0
// use aword to prevent overflow with 1 shl 31
if (stopbit-sreg.startbit<>AIntBits) then
bitmask:=(aword(1) shl (stopbit-sreg.startbit))-1
else
bitmask:=high(aword);
a_op_const_reg(list,OP_AND,subsetregdef,tcgint(bitmask),tmpreg);
{ If stopbit = (tcgsize2size[sreg.subsetregsize] * 8), then an
AND mask is unnecessary }
if (stopbit < GetRegBitSize()) then
begin
{ on x86(64), 1 shl 32(64) = 1 instead of 0
use aword to prevent overflow with 1 shl 31 }
if (stopbit-sreg.startbit<>AIntBits) then
bitmask:=(aword(1) shl (stopbit-sreg.startbit))-1
else
bitmask:=high(aword);
a_op_const_reg(list,OP_AND,subsetregdef,tcgint(bitmask),tmpreg);
end;
end;
end
else