Difference between revisions of "Absolute"
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(note little endian) |
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<syntaxhighlight> | <syntaxhighlight> | ||
− | // Example on x64 processor | + | // Example on little endian x64 processor |
Uses SysUtils; | Uses SysUtils; | ||
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// 333 is too large a value to fit in one byte | // 333 is too large a value to fit in one byte | ||
− | // 333 = 101001101 = 00000001 | + | // little-endian x64 - least significant byte is first in memory: |
+ | // 333 = 101001101 = 01001101 00000001 = 0x4D 0x01 = decimal: 77 1 | ||
WriteLn('firstByte: ' + IntToStr(firstByte)); // Outputs: firstByte: 77 | WriteLn('firstByte: ' + IntToStr(firstByte)); // Outputs: firstByte: 77 | ||
end. | end. | ||
</syntaxhighlight> | </syntaxhighlight> |
Revision as of 02:51, 19 September 2017
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The absolute modifier causes a variable to be stored at the same memory location as another variable.
// Example on little endian x64 processor
Uses SysUtils;
Var
anInt : Integer;
anotherInt : Integer absolute anInt;
firstByte : Byte absolute anInt;
begin
// with both Integer variables at the same memory location, a change to one is reflected
// in the other
anInt := 20;
WriteLn(IntToStr(anInt) + ' ' + IntToStr(anotherInt)); // Outputs: 20 20
// a value of 20 fits in the first byte:
WriteLn('firstByte: ' + IntToStr(firstByte)); // Outputs: firstByte: 20
anotherInt := 333;
WriteLn(IntToStr(anInt) + ' ' + IntToStr(anotherInt)); // Outputs: 333 333
// 333 is too large a value to fit in one byte
// little-endian x64 - least significant byte is first in memory:
// 333 = 101001101 = 01001101 00000001 = 0x4D 0x01 = decimal: 77 1
WriteLn('firstByte: ' + IntToStr(firstByte)); // Outputs: firstByte: 77
end.