Can we say that in Pascal the result of:
E1 shl E2
is of same type as E1 ?
(so if E1 is LongWord then result is LongWord also?)
What if there is an expression on left side:
(E1*x) shl E2
Will E1*x promote to 64 bits (on 64 bit target)?
See documentation on automatic type conversion (the remarks section
below table 3.3):
https://www.freepascal.org/docs-html/ref/refsu4.html#x26-26004r3
<https://www.freepascal.org/docs-html/ref/refsu4.html#x26-26004r3>
While this doesn't explicitly mention shift behaviour, it implies that
E1 and (E1*x) will be promoted to native sized integer if smaller. For
the first example, if E1 is a longword on a 32 bit machine, the result
should also be a longword.
But look at Delphi documentation:
https://docwiki.embarcadero.com/RADStudio/Sydney/en/Expressions_(Delphi)#Logical_.28Bitwise.29_Operators
"The operations x shl y and x shr y shift the value of x to the left or
right by y bits, which (if x is an unsigned integer) is equivalent to
multiplying or dividing x by 2^y; the result is of the same type as x"
My understanding is, that in case:
E1 shl E2 result is of E1 type (so if E1 is LongWord on 64 bit
platform result is still LongWord?)
Case
(E1*x) shl E2 is subject to native integer promotion I guess?
L.
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