[avr-gcc-list] Structure, bit-fields, optimization...

[Andrej Krpic]

Hello,

I have come to the problem, which I do not know how to solve.

If I define a structure

typedef structure MyStructTAG {
  uint8_t    ID;
  uint8_t   Status:1;
  uint8_t   Value:7;
  uint8_t   ModeBit1:1
  utin8_t  Value2:7;
  uint8_t   ModeBit2:1
  utin8_t  Value3:7;
} MyStruct, *MyStructPnt;

declare it,
MyStruct tmpStruct;

try to read it from eeprom:
One Way:

register uint8_t Temp;

Temp = eeprom_rb(address);
tmpStruct.ID = Temp;

Temp = eeprom_rb(address+1):
tmpStruct.Value = Temp&0x7F;
tmpStruct.Status = Temp&0x80;

Temp = eeprom_rb(address+2)
tmpStruct.Value2= Temp&0x7F;
tmpStruct.ModeBit1 = Temp&0x80;
.... and so on...

I think there has to be more efficient way... like:
*(&tmpStruct.ID + offset) = eeprom_rb(address + offset);
0<=offset<4

But the second method doesn't work. Any help is appreciated.

Also, I would like to know, "how" to program to make code smaller, tips &
tricks are very
welcome.

Thanks,
Andrej







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