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// http://lists.freepascal.org/lists/fpc-devel/2008-June/013919.html
uses SysUtils;
{$ASSERTIONS ON}
type
bit = 0..1;
t6bit = 0..63;
ByteBoundary = bitpacked record
bit0 : bit;
bit1_8 : byte;
bit9_15 : t6bit;
end;
TestByteBoundary = record
case boolean of
false : (AsWord : word);
true : (AsBits : ByteBoundary);
end;
procedure TestBits(b0 : bit; b1_8 : byte; b9_15 : t6bit);
var
Test : TestByteBoundary;
w : word;
begin
{$ifdef fpc_little_endian}
w := b0 + b1_8 shl 1 + b9_15 shl 9;
{$else}
w := b0 shl (16-1) + b1_8 shl (15-8) + b9_15 shl 1;
{$endif}
with Test, asBits do begin
bit0 := b0;
bit1_8 := b1_8;
bit9_15 := b9_15;
{$ifdef fpc_little_endian}
Writeln('Test : $', b0, ' + $', IntToHex(b1_8,2), ' << 1 + $',IntToHex(b9_15,2),' << 9');
write(' Expected : $',IntToHex(w,4),' Got : $',IntToHex((AsWord and $7fff),4));
if w = (Asword and $7fff) then
{$else}
Writeln('Test : $', b0, '<< 15 + $', IntToHex(b1_8,2), ' << 6 + $',IntToHex(b9_15,2),' << 1');
write(' Expected : $',IntToHex(w,4),' Got : $',IntToHex((AsWord and $fffe),4));
if w = (Asword and $fffe) then
{$endif}
writeln(' OK')
else
begin
writeln(' <--- Fail');
halt(1);
end;
end;
end;
procedure testproc;
var
Test : TestByteBoundary;
begin
Test.AsBits.bit0 := 0;
Test.AsBits.bit1_8 := $FF;
Test.AsBits.bit9_15 := 0;
writeln(IntToHex(Test.AsWord,4));
TestBits($1, $80, $00);
TestBits($1, $FE, $00);
TestBits($1, $FF, $00);
// These work
Test.AsBits.bit0 := 1;
Test.AsBits.bit1_8 := $80;
Test.AsBits.bit9_15 := 0;
{$ifdef fpc_little_endian}
assert((Test.AsWord and $7fff) = $0101, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $0101');
Test.AsBits.bit1_8 := $FE;
assert((Test.AsWord and $7fff) = $01FD, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $01FD');
// DOES NOT WORK ...
Test.AsBits.bit1_8 := 255;
assert((Test.AsWord and $7fff) = $01FF, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $01FF');
// Rest OK
Test.AsWord := 0;
Test.AsBits.bit9_15 := 1;
assert((Test.AsWord and $7fff) = $0200, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $0200');
Test.AsBits.bit9_15 := 32;
assert((Test.AsWord and $7fff) = $4000, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $4000');
Test.AsBits.bit9_15 := 62;
assert((Test.AsWord and $7fff) = $7C00, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $7C00');
Test.AsBits.bit9_15 := 63; // Correct
assert((Test.AsWord and $7fff) = $7E00, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $7E00');
Test.AsBits.bit0 := 1;
Test.AsBits.bit1_8 := 255;
Test.AsBits.bit9_15 := 63;
assert((Test.AsWord and $7fff) = $7FFF, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $7FFF');
{$else}
assert((Test.AsWord and $fffe) = $c000, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $C001');
Test.AsBits.bit1_8 := $FE;
assert((Test.AsWord and $fffe) = $FF00, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $FF00');
// DOES NOT WORK ...
Test.AsBits.bit1_8 := 255;
assert((Test.AsWord and $fffe) = $FF80, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $FF80');
// Rest OK
Test.AsWord := 0;
Test.AsBits.bit9_15 := 1;
assert((Test.AsWord and $fffe) = $0002, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $0002');
Test.AsBits.bit9_15 := 32;
assert((Test.AsWord and $fffe) = $0040, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $0040');
Test.AsBits.bit9_15 := 62;
assert((Test.AsWord and $fffe) = $007C, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $007C');
Test.AsBits.bit9_15 := 63; // Correct
assert((Test.AsWord and $fffe) = $007E, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $007E');
Test.AsBits.bit0 := 1;
Test.AsBits.bit1_8 := 255;
Test.AsBits.bit9_15 := 63;
assert((Test.AsWord and $fffe) = $FFFE, 'Is: ' + IntToHex(Test.AsWord,4) + ' Should be $FFFE');
{$endif}
end;
var
Test : TestByteBoundary;
begin
with Test, AsBits do begin
bit0 := 0;
bit1_8 := $FF;
bit9_15 := 0;
writeln(IntToHex(AsWord,4));
TestBits($1, $80, $00);
TestBits($1, $FE, $00);
TestBits($1, $FF, $00);
TestBits($0, $00, $01);
// These work
bit0 := 1;
bit1_8 := $80;
bit9_15 := 0;
{$ifdef fpc_little_endian}
assert((AsWord and $7fff) = $0101, 'Is: ' + IntToHex(Asword,4) + ' Should be $0101');
bit1_8 := $FE;
assert((AsWord and $7fff) = $01FD, 'Is: ' + IntToHex(Asword,4) + ' Should be $01FD');
// DOES NOT WORK ...
bit1_8 := 255;
assert((AsWord and $7fff) = $01FF, 'Is: ' + IntToHex(Asword,4) + ' Should be $01FF');
// Rest OK
AsWord := 0;
bit9_15 := 1;
assert((AsWord and $7fff) = $0200, 'Is: ' + IntToHex(Asword,4) + ' Should be $0200');
bit9_15 := 32;
assert((AsWord and $7fff) = $4000, 'Is: ' + IntToHex(Asword,4) + ' Should be $4000');
bit9_15 := 62;
assert((AsWord and $7fff) = $7C00, 'Is: ' + IntToHex(Asword,4) + ' Should be $7C00');
bit9_15 := 63; // Correct
assert((AsWord and $7fff) = $7E00, 'Is: ' + IntToHex(Asword,4) + ' Should be $7E00');
bit0 := 1;
bit1_8 := 255;
bit9_15 := 63;
assert((AsWord and $7fff) = $7FFF, 'Is: ' + IntToHex(Asword,4) + ' Should be $7FFF');
{$else}
assert((AsWord and $fffe) = $c000, 'Is: ' + IntToHex(Asword,4) + ' Should be $C000');
bit1_8 := $FE;
assert((AsWord and $fffe) = $FF00, 'Is: ' + IntToHex(Asword,4) + ' Should be $FF00');
// DOES NOT WORK ...
bit1_8 := 255;
assert((AsWord and $fffe) = $FF80, 'Is: ' + IntToHex(Asword,4) + ' Should be $FF80');
// Rest OK
AsWord := 0;
bit9_15 := 1;
assert((AsWord and $fffe) = $0002, 'Is: ' + IntToHex(Asword,4) + ' Should be $0002');
bit9_15 := 32;
assert((AsWord and $fffe) = $0040, 'Is: ' + IntToHex(Asword,4) + ' Should be $0040');
bit9_15 := 62;
assert((AsWord and $fffe) = $007C, 'Is: ' + IntToHex(Asword,4) + ' Should be $007C');
bit9_15 := 63; // Correct
assert((AsWord and $fffe) = $007E, 'Is: ' + IntToHex(Asword,4) + ' Should be $007E');
bit0 := 1;
bit1_8 := 255;
bit9_15 := 63;
assert((AsWord and $fffe) = $FFFE, 'Is: ' + IntToHex(Asword,4) + ' Should be $FFFE');
{$endif}
end;
testproc;
end.
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