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Honored Contributor
Honored Contributorgcc alignment
I'm surprised. I have a C++ code that fills a char array and there seems to be an alignment problem with g++. See below: char* response = new char;
response = 0;
unsigned int* dataSize = (uns...
Altera_ForumHonored Contributor
Honored ContributorFrom the manual:
--- Quote Start --- STW Description Computes the effective byte address specified by the sum of rA and the instruction's signed 16-bit immediate value. Stores rB to the memory location specified by the effective byte address. the effective byte address must be word aligned. If the byte address is not a multiple of 4, the operation is undefined. --- Quote End --- Seems that it is not gcc doing this. The compiled code actually uses the value pointer+1 to do a STW (store word) instruction. It is the NIOS instruction set that aligns the store word instruction (it appears to truncate the low 2 bits of the store address for STW, but the manual says "undefined", meaning that it might be different in a different version of the processor). No way around it. To store at byte addresses, you are going to have to use bytes, or use a different processor, or write your own routine for storing words at byte addresses (another version of "using bytes");
