On 01/19/2015 07:25 PM, Maciej W. Rozycki wrote: > On Mon, 19 Jan 2015, Maciej W. Rozycki wrote: > >>> sorry i might be missing something but why do you think this is an >>> important bug fix that should go into 3.19? the way i read the code it >>> seems that it can't go wrong at the moment. >> >> We shouldn't be using trapping instructions for address calculation. >> These macros have been wrong since the beginning, the MSA instructions >> they correspond to do not trigger an exception on an integer overflow in >> address calculation (none of the MIPS instruction does). > > And BTW, it is a bug in GAS too, that it does not accept ADDI for R6 -- > it should treat the instruction as a macro and expand it to an equivalent > LI + ADD sequence (using $at or `rd', if available, as a temporary to > store the immediate). Similarly to how microMIPS DADDI is handled for > example (where the hardware instruction has an unusually limited range of > the immediate argument, however GAS accepts any 16-bit). > > Maciej > CC'ing Matthew -- markos
