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* attempt to fix bitpacked records with qwords in them (tw36156) when cross-compiling to big endian targets from x86. essentially the x86 shifting workarounds in the code already weren't covering all corner cases.

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git-svn-id: trunk@48773 -
This commit is contained in:
Károly Balogh 2021-02-21 23:00:41 +00:00
parent 6beb28316e
commit 0ca1e2fb42
1 changed files with 22 additions and 4 deletions
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26
compiler/ngtcon.pas
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@ -328,6 +328,25 @@ function get_next_varsym(def: tabstractrecorddef; const SymList:TFPHashObjectLis
{$push}
{$r-}
{$q-}
{ to work around broken x86 shifting, while generating bitmask }
function getbitmask(len: byte): aword;
begin
if len >= (sizeof(result) * 8) then
result:=0
else
result:=aword(1) shl len;
result:=aword(result-1);
end;
{ shift left, and always pad the right bits with zeroes }
function shiftleft(value: aword; count: byte): aword;
begin
if count >= (sizeof(result) * 8) then
result:=0
else
result:=(value shl count) and (not getbitmask(count));
end;
{ (values between quotes below refer to fields of bp; fields not }
{ mentioned are unused by this routine) }
{ bitpacks "value" as bitpacked value of bitsize "packedbitsize" into }
@ -342,16 +361,15 @@ function get_next_varsym(def: tabstractrecorddef; const SymList:TFPHashObjectLis
if (target_info.endian=endian_big) then
begin
{ bitpacked format: left-aligned (i.e., "big endian bitness") }
{ work around broken x86 shifting }
if (AIntBits<>bp.packedbitsize) and
if (bp.packedbitsize<AIntBits) and
(bp.curbitoffset<AIntBits) then
bp.curval:=bp.curval or ((value shl (AIntBits-bp.packedbitsize)) shr bp.curbitoffset);
bp.curval:=bp.curval or (shiftleft(value,AIntBits-bp.packedbitsize) shr bp.curbitoffset);
shiftcount:=((AIntBits-bp.packedbitsize)-bp.curbitoffset);
{ carry-over to the next element? }
if (shiftcount<0) then
begin
if shiftcount>=-AIntBits then
bp.nextval:=(value and ((aword(1) shl (-shiftcount))-1)) shl
bp.nextval:=(value and getbitmask(-shiftcount)) shl
(AIntBits+shiftcount)
else
bp.nextval:=0;