I noticed today that GCC generates for:
static __uint32_t sumu32; // unsigned int
static __uint64_t sumu64; // unsigned long
void addStuff(__uint64_t a64, __uint64_t b64, __uint32_t a32, __uint32_t b32 ) {
sumu32 = a32 + b32;
sumu64 = a64 + b64;
}
the following:
117: **** sumu32 = a32 + b32;
77 .loc 1 117 0
78 0044 5810B1C4 l %r1,452(%r11) # sumu32.6, a32
79 0048 5A10B1C0 a %r1,448(%r11) # sumu32.6, b32
80 004c C41F0000 strl %r1,sumu32 # sumu32.6, sumu32
80 0000
118: **** sumu64 = a64 + b64;
81 .loc 1 118 0
82 0052 E310B1D0 lg %r1,464(%r11) # sumu64.7, a64
82 0004
83 0058 E310B1C8 ag %r1,456(%r11) # sumu64.7, b64
83 0008
84 005e C41B0000 stgrl %r1,sumu64 # sumu64.7, sumu64
Have I grossly misunderstood something there? Can I really operate on an
unsigned integer with signed operations and get the correct results?
Best wishes / Mejores deseos / Meilleurs vœux
Ian ...
