🚀 go-pugleaf

In article <1992Oct27.071744.4871@netcom.com> rfg@netcom.com (Ronald F. Guilmette) writes:
|
|The Subject line say it all.  I've read section 3.2.1.2 and it appears that
|the authors of the ANSI/ISO C standard went out of their way to define
|the value of every conceivable arithmetic conversion *except* the conversion
|of a negative signed integral value to an unsigned integral value of the
|same size.
|
|If anyone has evidence to the contrary, please share it.  (Please don't
|provide opinions... provide citations instead.  Thanks.)

I think the standard defines rather well what happens to it:

3.2.1.2 Signed and unsigned integers

`When a signed integer is converted to an unsigned integer with equal
or greater size, if the value of signed integer is nonnegative, its
value is unchanged. Otherwise: if the unsigned integer has greater
size, the signed integer is first promoted to the signed integer
corresponding to the unsigned integer; the value is converted to
unsigned by adding to it one greater than the largest number that
can be represented in the unsigned integer type.'

On (normal?) two complement implementations nothing happens, i.e.
the bit pattern remains the same as it was. If the size of an
unsigned int is larger than the size of a signed int, there will
occur sign bit extension, e.g. sizeof(int) = 2; sizeof(unsigned int) = 4.

-1 (0xffff) -> -1 (0xffffffff) -> 0xffffffff + 0x100000000 = 0xffffffff

kind regards,

Jos aka jos@and.nl