Hi Wolfgang,
when copying val from 'data[bytecount++]' it is common practice that val if of the same type as the array elements. So val should be unsigned char.
I changed the sign check into a 'val & 0x80', which I think is fine an clean.
Matthias
On Monday 05 November 2007 20:21, Wolfgang Denk wrote:
In message 472F1393.7040306@inaccessnetworks.com you wrote:
Wolfgang Denk wrote:
In message 472752F9.9000307@inaccessnetworks.com you wrote:
The following patch fixes a bug in the slave serial programming mode for the xilinx spartan2 FPGA. A "char val" is declared, but it is used as a signed char. The check for negative value (<0) is always true on arm, or any other platform in which the char is not signed by default. As a result the FPGA cannot be programmed.
I have to admit that I hate to see "signed char" in the code. Is there any special reaso why "val" has to be a "char" type? Why not making it an "int" ?
Another way to do this safely is to declare it as an "unsigned char" and instead of doing "val < 0", do "val & 0x80". I don't like the current code either. Shifting a signed char and testing for negativity is definitely not the best way to test that the MSB is set.
So let me repeat my question: is there any special reason why "val" has to be a "char" type? Why not making it an "int" ?
Best regards,
Wolfgang Denk