Hi,
Win32 .exe compiled on Win64 computer, latest SVN build.
I am trying to multiply 2 Integers (Declared as LongInt but sometimes
need to use it as LongWord) and put the result into a QWord (64bit
unsigned) result variable on Win32.
However, it seems that the result is always cut to 32bit.
Checked the assembler window inside Lazarus and there is a "mull"
instruction and immediately after that there is a zeroing out of the
"EDX" register cutting the "EDX:EAX" result short.
Simplified example:
var
A: LongInt;
C: QWord;
begin
A := $12345678;
C := LongWord(A) * LongWord(255);
.
.
.
end;
Am I doing something wrong in the code to accomplish this?
in Assembly it could be something like:
asm//Intel syntax
mov edx, $12345678
mov eax, 255
mul edx
...store
end;
which would store the 64 bit result from EDX:EAX
However, the code actually generated is something like:
asm//Lazarus syntax
mull ...
mov $0x0, %edx <- why is this here?
then stores both eax and edx into the variable
end;
Thanks for any help,
AB
PS: Any way to see the assembler window in Intel assembly syntax?
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