On 02/03/2022 17:29, Barbier, Renaud via Gcc-help wrote: > I am building a boot loader (barebox) with gcc 10.2.0 for a NXP LS1021A for which I intend to use SPD. > > The SPD structure for DDR3 (struct ddr3_spd_eeprom )can be found here: https://git.pengutronix.de/cgit/barebox/tree/include/ddr_spd.h > > The problem I have is that the field after the union are not packed: > > .... > } registered; > unsigned char uc[57]; /* 60-116 Module-Specific Section */ ==> uc[56] is at the right place offset 116 > } mod_section; > > /* Unique Module ID: Bytes 117-125 */ > unsigned char mmid_lsb; /* 117 Module MfgID Code LSB - JEP-106 */ ===> mmid_lsb end up at offset 120 instead of offset 117 > > I tried the __packed attribute without effect > > This is the debug output showing the offset from the start of SPD structure: > uc[56]@ = 0x1000e2cc, 116 > mmid_lsb@ = 0x1000e2d0, 120 ==> should be 117. > > Is there a bug in 10.2.0 that I have not found or a parameter I have not used to build the boot loader that could fix this problem. > > Cheers, > R > It seems fine to me when I tried it on godbolt : <https://godbolt.org/z/r1joYd135>
