Christian Schmitz wrote:
> Tim Jones <[EMAIL PROTECTED]> wrote:
>
>
>> Thanks Christian. Since 'r' is going to be modified by the algorithm,
>> shouldn't the entry be "ByRef r As MemoryBlock"?
>>
>
> do you modify the reference or the content?
> Byref is to modify the reference.
> e.g. to assign a new memoryblock to it in the function.
>
Ah, since I'm modifying the content, I shouldn't use ByRef in the
definition. But, will I need to use ByRef in the call from RB as I do
if calling a shared library declare?
> Also, am I using the
> correct identifier for this type of function (accept 3 memoryblocks,
> modify the contents of the 3rd) when I use "REALNoImplementation"?
>
>
> looks correct.
>
>
>> The change above works and my ModularExp() method nows autocompletes in
>> the IDE editor - however, the helper text does not show up in the IDE's
>> status bar.
>>
>
> You will get used to it.
>
Oh, another of *THOSE* quirky things ...
>
>
>>
>> I get a hard crash.
>>
>
> your C function is not declared to take REALmemoryblocks.
>
Ah, so my current function call code looks like:
void ModularExp(unsigned short *base,
unsigned short *power,
unsigned short *result)
and the actual module's code expects pointers to 3 arrays of 64 unsigned
shorts. When I look up the type definition for REALmemoryBlock, I can't
find a typedef, so I should assume that, in this case, a REALmemoryBlock
is just a struct? What should be changed from normal C code to enable
the memoryblock manipulation?
Here's the entire function in C. The arrays "one[]" and "exp[]" are
predefined arrays of 64 unsigned shorts. And the variable BIGNUM_SHORTS
is 64.
void ModularExp(unsigned short *base, unsigned short *power, unsigned
short *result) {
unsigned short z, sqr[BIGNUM_SHORTS], exp[BIGNUM_SHORTS];
int i;
for(i=0; i<BIGNUM_SHORTS; i++) {
result[i] = one[i];
exp[i] = power[i];
}
modular_product(base, one, sqr);
for(;;) {
if (exp[0] & 1)
montgomery_reduction(sqr, result, result);
z = 0;
for(i=0; i<BIGNUM_SHORTS-1; i++) {
exp[i] = (exp[i] >> 1) | ((exp[i+1] & 1) << 15);
z |= exp[i];
}
exp[BIGNUM_SHORTS-1] >>= 1;
z |= exp[BIGNUM_SHORTS-1];
if (z == 0)
break;
montgomery_reduction(sqr, sqr, sqr);
}
modular_product(result, rp, result);
}
Am I just going to modify the calling parameters and then deal with the
arrays internally as I do in the normal C program, or are the required
changes going to move into my other functions as well?
Thanks,
Tim
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