A1222 support in the SDK and problems

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sailor

Re: A1222 support in the SDK and problems

Posted on: 1/23 16:00 #61

Not too shy to talk

I tried to link it with gcc 11.2 and 10.3, still receive allingnment error.

Next I will try pointers workaround.

@all, thanks for advice

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salass00

Re: A1222 support in the SDK and problems

Posted on: 1/24 17:59 #62

Just can't stay away

@sailor

You could use a method similar to what has been used in m68k-amigaos C code to allocate long word aligned structures like FileInfoBlock from the stack:


static char align_buffer[3*sizeof(double)-1];

double *T1ptr;

double *T2ptr;

#define T1 (*T1ptr)

#define T2 (*T2ptr)



__attribute__((constructor))

static void __init_T1T2(void)

{

    T1ptr = (double *)(((uintptr_t)align_buffer + sizeof(double) - 1) & ~(sizeof(double) - 1));

    T2ptr = T1ptr + 1;

}

If T1 and T2 were arrays instead of simple double variables you could even make use of C's pointer/array equivalence to get rid of the ugly macros.

sailor

Re: A1222 support in the SDK and problems

Posted on: 1/24 19:59 #63

Not too shy to talk

@salass00
interesting idea - many thanks. For the first time I heard about constructor attribute. Looks nice, on weekend I will test.

Before you post this advice, I had in plan more dirty solution, something like:
double Tarray[3];
double *pT,*pT1;
pT= (double*)((long)(Tarray +1) - (long)(Tarray % 8));
pT1= pT+1;

Thx!

Edited by sailor on 2025/1/24 20:47:35
Edited by sailor on 2025/1/24 20:48:45
Edited by sailor on 2025/1/24 20:53:08
Edited by sailor on 2025/1/24 20:53:41

sailor

Re: A1222 support in the SDK and problems

Posted on: 1/25 12:31 #64

Not too shy to talk

@salass00
thanks, it works nice!
For global vars and global arrys too.

Edited by sailor on 2025/1/25 12:58:29
Edited by sailor on 2025/1/25 12:58:47

sailor

Re: A1222 support in the SDK and problems

Posted on: 1/30 14:49 #65

Not too shy to talk

@salass00Quote:

salass00 wrote:@sailor

You could use a method similar to what has been used in m68k-amigaos C code to allocate long word aligned structures like FileInfoBlock from the stack:

static char align_buffer[3*sizeof(double)-1]; double *T1ptr; double *T2ptr; #define T1 (*T1ptr) #define T2 (*T2ptr) __attribute__((constructor)) static void __init_T1T2(void) { T1ptr = (double *)(((uintptr_t)align_buffer + sizeof(double) - 1) & ~(sizeof(double) - 1)); T2ptr = T1ptr + 1; }

If T1 and T2 were arrays instead of simple double variables you could even make use of C's pointer/array equivalence to get rid of the ugly macros.

If I used single dimension array, as you said alignment is easy for array[A]:


static char align_buffer[(A+1)*sizeof(double)-1];

double *array;

__attribute__((constructor))

static void __init_array(void)

{

    array = (double *)(((uintptr_t)align_buffer + sizeof(double) - 1) & ~(sizeof(double) - 1));

}

And please, how it will work for multidimensional arrays - like array[A][B][C]? Should I use this?


static char align_buffer[(A*B*C+1)*sizeof(double)-1];

double (*array)[A][B][C];

__attribute__((constructor))

static void __init_array(void)

{

    array = (double *)(((uintptr_t)align_buffer + sizeof(double) - 1) & ~(sizeof(double) - 1));

}

and in the rest of code use normally array[a][b][c] ?

salass00

Re: A1222 support in the SDK and problems

Posted on: Yesterday 19:23 #66

Just can't stay away

@sailor

I could be wrong but I don't think definining a pointer to a multi-dimensional array will work. In my experience multi-dimensional arrays in C are quite limited in how they can be used so I almost never use them in my code.

What should work however is something like (not quite as elegant):


static char align_buffer[(A*B*C+1)*sizeof(double)-1];

double *array[A][B];

__attribute__((constructor))

static void __init_array(void)

{

    double *p = (double *)(((uintptr_t)align_buffer + sizeof(double) - 1) & ~(sizeof(double) - 1));

    int i, j;



    for (i = 0; i < A; i++)

    {

        for (j = 0; j < B; j++)

        {

            array[i][j] = p;

            p += C;

        }

    }

}

flash

Re: A1222 support in the SDK and problems

Posted on: Yesterday 20:18 #67

Just popping in

How can we get a fixed version of GCC to avoid all these workarounds/hacks?
Is there a guy able to fix it for a native version of GCC?

Memento audere semper!

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