Am Sun, 30 Jun 2013 07:07:23 -0400
schrieb "Tyro[17]" <rid...@yahoo.com>:
> What is the equivalent of memcpy
>
> module memcopy;
>
> immutable ADDRESS_BUS_SIZE = 20; // 2^20 address bus
> byte memory[1 << ADDRESS_BUS_SIZE];
>
> void main()
> {
> ushort val = 12345;
>
> for (int i = 0x12340; i < 0x1234A; i+= 2) {
> memcpy (&memory[i], &val, sizeof val); // D way???
> val++;
> }
>
> for (int i = 0x12340; i < 0x1234A; i+= 2) {
> memcpy (&val, &memory[i], sizeof val); // D way???
> writefln("%x", val);
> }
> }
>
> achieved in D? I am trying not to use memcpy or any function from the C API.
>
> Thanks,
While they are in the C stdlib, there is nothing really C
specific about them. Just use them. In your case GCC would
recognize a memcpy call with known length (2 bytes) and inline
the call. From there I guess the optimizer can figure
something out that runs fast.
That said how about this in D:
ushort val = 12345;
for (int i = 0x12340; i < 0x1234A; i+= 2)
*cast(ushort*) &memory[i] = val++;
for (int i = 0x12340; i < 0x1234A; i+= 2) {
val = *cast(ushort*) &memory[i]
writefln("%04x", val);
}
--
Marco
