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Add assembler implementation of Move.

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git-svn-id: trunk@42155 -
(cherry picked from commit 009c87156a)
This commit is contained in:
Jeppe Johansen 2019-06-01 15:39:09 +00:00 committed by florian
parent 18ba7fc23a
commit 915e48c675
1 changed files with 37 additions and 31 deletions
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68
rtl/avr/avr.inc
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@ -32,37 +32,43 @@ procedure fpc_cpuinit;{$ifdef SYSTEMINLINE}inline;{$endif}
{$define FPC_SYSTEM_HAS_MOVE}
procedure Move(const source;var dest;count:SizeInt);[public, alias: 'FPC_MOVE'];
var
pdest,psrc,pend : pbyte;
begin
if (@dest=@source) or (count<=0) then
exit;
if (@dest<@source) or (@source+count<@dest) then
begin
{ Forward Move }
psrc:=@source;
pdest:=@dest;
pend:=psrc+count;
while psrc<pend do
begin
pdest^:=psrc^;
inc(pdest);
inc(psrc);
end;
end
else
begin
{ Backward Move }
psrc:=@source+count;
pdest:=@dest+count;
while psrc>@source do
begin
dec(pdest);
dec(psrc);
pdest^:=psrc^;
end;
end;
procedure Move(const source;var dest;count:SizeInt);[public, alias: 'FPC_MOVE']; assembler; nostackframe;
asm
push r28
push r29
movw r26, r24 // Src=X
movw r28, r22 // Dest=Y
movw r30, r20 // Count=Z
cp r1, r30
cpc r1, r31
brge .Lexit // if 0 >= Count
cp r28, r26
cpc r29, r27
breq .Lexit // if dest = source
brlo .LForwardMove // if dest < source
// Add count to both pointers
add r26, r30
adc r27, r31
add r28, r30
adc r29, r31
.LBackwardMove:
ld r18, -X
st -Y, r18
sbiw Z, 1
brne .LBackwardMove
rjmp .Lexit
.LForwardMove:
ld r18, X+
st Y+, r18
sbiw Z, 1
brne .LForwardMove
.Lexit:
pop r29
pop r28
end;