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SeeCwriter
Joined: 18 Nov 2013
Posts: 160
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| Pointers to an array |
 Posted: Mon Nov 30, 2020 10:41 am |
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Can I create an array of 32-bit integers and assign that to a pointer? I don't have hardware to test this right now, and when I tried it a few years ago it didn't work. It compiled but the program didn't do what I wanted.
Example:
| Code: |
signed int32 *pData[];
const signed int32 mydata[] =
{
0x01000002,
0x02000001,
0x03000046,
0x05000390,
0x05000000,
0x06002F4A,
0x0700054D,
0x08C9BEFF,
0x09573FFF,
0x0A002047,
0x0B0F8061,
0x0F000081,
0x04200000
};
void main()
{
byte len = sizeof(mydata) >> 2;
pData = mydata;
Dosomething(pData, len);
}
void Dosomething( int32 *d, byte num )
{
}
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I'm using v5.097 of PCWH and a 12LF1552 pic. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19505
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| Posted: Mon Nov 30, 2020 11:51 am |
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Historically, the problem would have been this one word. 'Const'.
The problem is that the PIC is a Harvard architecture processor. On this
the RAM, and program memory are in different memory spaces. Const
puts the variable into the program memory space. Result a RAM pointer
won't actually point to it....
Now you can use ROM instead of const, which tells the compiler to store
the data so a ROM * pointer can be constructed to it. However you do have
to declare your function so it expects a ROM * pointer.
If you look at my SSD1306 driver in the code library this uses ROM *
pointers, so you can see how these can be used. Beware though that
CCS 5.096 has an issue with these (fixed in 5.097, and OK on earlier
releases). |
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SeeCwriter
Joined: 18 Nov 2013
Posts: 160
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| Posted: Mon Nov 30, 2020 12:04 pm |
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| I will check it out. Thanks. |
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