How to declare 2-D array ?

[Mian Qi]

When I declared as this:

 45 bool keyPad[4][4] = {
 46   {0, 0, 0, 0},
 47   {0, 0, 0, 0},
 48   {0, 0, 0, 0},
 49   {0, 0, 0, 0}
 50 };
 51 
 52 bool ledArray[8][8] = {
 53   {0, 0, 0, 0, 0, 0, 0, 0},
 54   {0, 0, 0, 0, 0, 0, 0, 0},
 55   {0, 0, 0, 0, 0, 0, 0, 0},
 56   {0, 0, 0, 0, 0, 0, 0, 0},
 57   {0, 0, 0, 0, 0, 0, 0, 0},
 58   {0, 0, 0, 0, 0, 0, 0, 0},
 59   {0, 0, 0, 0, 0, 0, 0, 0},
 60   {0, 0, 0, 0, 0, 0, 0, 0}
 61 };
 62 

It was prompted:

?ASlink-Warning-Undefined Global 'FF' referenced by module 'keypad_ledarray'

and, when I declared as this:

 45 bool keyPad[4][4] = {
 46   0, 0, 0, 0,
 47   0, 0, 0, 0,
 48   0, 0, 0, 0,
 49   0, 0, 0, 0
 50 };
 51 
 52 bool ledArray[8][8] = {
 53   0, 0, 0, 0, 0, 0, 0, 0,
 54   0, 0, 0, 0, 0, 0, 0, 0,
 55   0, 0, 0, 0, 0, 0, 0, 0,
 56   0, 0, 0, 0, 0, 0, 0, 0,
 57   0, 0, 0, 0, 0, 0, 0, 0,
 58   0, 0, 0, 0, 0, 0, 0, 0,
 59   0, 0, 0, 0, 0, 0, 0, 0,
 60   0, 0, 0, 0, 0, 0, 0, 0
 61 };
 62 

it was prompted:

keypad+ledarray.c:121: error 69: struct/union/array '': initialization needs curly braces
keypad+ledarray.c:121: error 69: struct/union/array '': initialization needs curly braces
keypad+ledarray.c:121: error 69: struct/union/array '': initialization needs curly braces
keypad+ledarray.c:121: error 69: struct/union/array '': initialization needs curly braces
keypad+ledarray.c:47: warning 147: excess elements in array initializer after 'keyPad'
keypad+ledarray.c:121: error 69: struct/union/array '': initialization needs curly braces
keypad+ledarray.c:121: error 69: struct/union/array '': initialization needs curly braces
keypad+ledarray.c:121: error 69: struct/union/array '': initialization needs curly braces
keypad+ledarray.c:121: error 69: struct/union/array '': initialization needs curly braces
keypad+ledarray.c:121: error 69: struct/union/array '': initialization needs curly braces
keypad+ledarray.c:121: error 69: struct/union/array '': initialization needs curly braces
keypad+ledarray.c:121: error 69: struct/union/array '': initialization needs curly braces
keypad+ledarray.c:121: error 69: struct/union/array '': initialization needs curly braces
keypad+ledarray.c:54: warning 147: excess elements in array initializer after 'ledArray'

So, how to declare a 2-D array in SDCC ?

[Benedikt Freisen]

The first variant is the correct approach, because SDCC does not currently support the second variant, even though it is valid C.
I have no idea what is going on with the ASlink warning. It is possible that you found a bug.
If the array is a global variable, you could omit the explicit zero-initialization as a workaround, because global variables are implicitly zeroed.

[Philipp Klaus Krause]

Yes, the first one should work. The error message "?ASlink-Warning-Undefined Global 'FF' referenced by module 'keypad_ledarray'" looks like it is about an unrelated issue. Can you provide a compile- and linkable code sample to reproduce that problem?

[Mian Qi]

Hier:

[Mian Qi]

If the array is a global variable, you could omit the explicit zero-initialization as a workaround, because global variables are implicitly zeroed.

This works.

[Janko Stamenović]

I think the FF about which the linker complains must be here:

void delay(void) {

    __asm
    mov R7, #FF

Instead of #FF there should be either #0xFF or #255, as in this assembler # just means something like "the number argument of the assembly instruction follows" and 0x is a prefix for hexadecimal numbers.

[Philipp Klaus Krause]

Yes.

#0xff or #0xFF would be the number 0xff. #FF is the value of the symbol FF (i.e a symbol named FF which would get assigned a value by the linker), but since there is no symbol FF, you get an error message at link time.

[Mian Qi]

Thanks, when I modified "0xFF", neither of the 2 errors is shown. And, I found

 55 bool keyPad[4][4] = {
 56   {0, 0, 0, 0},
 57   {0, 0, 0, 0},
 58   {0, 0, 0, 0},
 59   {0, 0, 0, 0}
 60 };

was OK, and

 45 /*
 46 bool keyPad[4][4] = { 
 47   0, 0, 0, 0,
 48   0, 0, 0, 0,
 49   0, 0, 0, 0,
 50   0, 0, 0, 0
 51 };
 52 */

would trigger "error 69: struct/union/array '': initialization needs curly braces".

I attached this feature description here, maybe it is useful for someone else.

[Konstantin Kim]

The intriguing aspect of the next two lines is that they follow C23 syntax correctly but SDCC only initialize the first element:

bool keyPad[4]     = {};
bool keyPad2[4][4] = {{}};

bug?

[Mian Qi]

I think this are not bug, since SDCC is a free and open source software, it should trade in-between feature and cost, so what's important is knowing what is can and what it can not, and for those it can, also know how it does them.