I have a function that needs to access the upper byte of an address. I am working on writing an interface to a i2c serial eeprom, and I would like to pass in an address to make the function more user friendly. Anyway here is the code I have and the errors I get:

unsigned char eeprom_read(char *readAddr) {
  unsigned char retVal;
  unsigned char firstByte;
  unsigned char secondByte;

  // Calculate first and second bytes.
  firstByte = (unsigned char)((0xA0) | ((readAddr >> 7) & 0x0E));
  secondByte = (unsigned char)readAddr;

...

[root@localhost final]# sdcc i2c.c
i2c.c(52):warning *** 'auto' variable 'retVal' may be used before initialization at i2c.c(52)
i2c.c(52):warning *** in function i2c_send_byte unreferenced function argument : 'sendByte'
i2c.c(68):warning *** 'auto' variable 'retVal' may be used before initialization at i2c.c(68)
i2c.c(77):error   *** invalid operand for shift operator
i2c.c(77):warning *** left & right types are
_generic * char ,char
i2c.c(88):error   *** code not generated for 'eeprom_read' due to previous errors

If anyone knows how to get access to just the second byte of this generic pointer please let me know. I have thought about using the registers that the compiler uses to pass the argument, but I don't know how reliable that would be.

Any help or ideas would be great.

Tyson Harding