[?]v1.40-2.50: Constant declarations issue

[Dany]

Hi, I see some odd things when using "SizeOf" and "Hi"/"Lo" together with typecasting in constant declarations. As far as I can test the problem does not occur when the destination is a variable.

The following declarations work OK (meaning the content of Config1 is "1000" if interpreted as word):

Code: Select all

const ReportDescriptor: array[1000] of byte = (
    0x06, 
    0xA0
    // ....
);
const Config1 : array[2] of byte = (
    Lo(SizeOf(ReportDescriptor)),
    Hi(SizeOf(ReportDescriptor))
);

The code below is not OK, the content of Config1 is zero (both bytes, while they should contain "1000" if interpreted as a word):

Code: Select all

const ReportDescriptor: array[1000] of byte = (
    0x06, 
    0xA0
    // ....
);
const Config1 : array[2] of byte = (
    Lo(word(SizeOf(ReportDescriptor))), // <-------- typecast
    Hi(word(SizeOf(ReportDescriptor)))  // <-------- typecast
);

Listfile extract:

Code: Select all

;HiLo.mpas,16 :: _Config2
0x04AA        0x0000 ;_Config2+0
; end of _Config2
;HiLo.mpas,11 :: _Config1
0x04AC        0x03E8 ;_Config1+0
; end of _Config1

I do need the typecast because following code gives a compilation error (and I would like to make my code independant of the size of an object like "ReportDescriptor"):

Code: Select all

const ReportDescriptor: array[50] of byte = ( // <--- value <256 now
    0x06, 
    0xA0
    // ....
);
const Config1 : array[2] of byte = (
    Lo(SizeOf(ReportDescriptor)), 
    Hi(SizeOf(ReportDescriptor))  // <-------- compilation error
);

see http://www.mikroe.com/forum/viewtopic.php?t=19839.

Thanks in advance!

[Dany]

Situation has changed with the v3.00 bèta version:
"Hi" for values < 256 give still an error. The second definition "Config1" now gives a "Bad aggregate definition" compiler error.

Comment fro mE:

Hi() is forbidden for RAM variables which are less than two bytes. However, we shall allow this for consts, there is no reason for forbidding it.

[srdjan]

Hi,
hi, higher, highest now allowed for constants with less bytes.

This:

Code: Select all

const ReportDescriptor: array[1000] of byte = (
    0x06,
    0xA0
    // ....
);
const Config1 : array[2] of byte = (
    Lo(word(SizeOf(ReportDescriptor))), // <-------- typecast
    Hi(word(SizeOf(ReportDescriptor)))  // <-------- typecast
);

Will remain as bug for now, since release is coming this week.
Thanks.

[Dany]

Thanks!

[Dany]

Hi,

in mP v3.20 the "Bad aggregation definition"compiler error is gone , and the function "Hi" does not give any longer a compiler error in constructions as below in Config3 ,
but the second version of Config1 (see config2 below) gives a wrong result :

Code: Select all

program HiLo;

{ Declarations section }

const ReportDescriptor: array[1000] of byte = (
    0x06,                    // USAGE_PAGE (Vendor Defined)
    0xA0
    // ....
);

const Config1 : array[2] of byte = (
    Lo(SizeOf(ReportDescriptor)),
    Hi(SizeOf(ReportDescriptor))
);

const Config2 : array[2] of byte = (
    Lo(word(SizeOf(ReportDescriptor))),
    Hi(word(SizeOf(ReportDescriptor)))
);


const TestDescriptor : array[255] of byte = (1,2,3);

const Config3 : array[2] of byte = (
    Lo(SizeOf(TestDescriptor)),
    Hi(SizeOf(TestDescriptor))
);


type TBufferDescriptor =
     record
       Status: byte;
       ByteCount: byte;
       Address: word;
     end;

const P2: ^byte;

begin
  { Main program }

  P2 := @Config1;
  P2 := @Config2;
  P2 := @Config3;

end.

Content of the listfile:

Code: Select all

;HiLo.mpas,24 :: _Config3
0x0529	0x00FF ;_Config3+0               <-- correct
; end of _Config3
;HiLo.mpas,16 :: _Config2
0x052B	0x0201 ;_Config2+0               <-- should be 0x03E8 :cry: 
; end of _Config2
;HiLo.mpas,11 :: _Config1
0x052D	0x03E8 ;_Config1+0               <-- correct
; end of _Config1

[srdjan]

I'll just quote myself:

Hi,
hi, higher, highest now allowed for constants with less bytes.

This:

Code: Select all

const ReportDescriptor: array[1000] of byte = (
    0x06,
    0xA0
    // ....
);
const Config1 : array[2] of byte = (
    Lo(word(SizeOf(ReportDescriptor))), // <-------- typecast
    Hi(word(SizeOf(ReportDescriptor)))  // <-------- typecast
);

Will remain as bug for now, since release is coming this week.
Thanks.