On 01/11/2015 11:34 PM, Maciej W. Rozycki wrote: > On Fri, 19 Dec 2014, Markos Chandras wrote: > >>>> The use of "add" instruction for immediate operations is wrong and >>>> relies to gas being smart enough to notice that and replace it with >>>> either addi or addui. However, MIPS R6 removed the addi instruction >>>> so, fix this problem properly by using the correct instruction >>>> directly. > > Not true, depending on the arguments the ADD assembly macro expands to > either of the ADD and the ADDI hardware instructions; where an immediate > outside the 16-bit signed range is used it also expands to a longer > sequence involving LUI and the actual operation is ADD. It never expands > to ADDIU (which I gather you meant). > >>> This is another case of the use of "add" being a real bug. We should >>> never have faulting instructions like this in the kernel. >>> >>> Can you send all patches in this set that fix this bug as a separate >>> patch? Since they are obviously correct, and really should be used by >>> all non-R6 processors, we can get them in sooner that the entire R6 thing. >>> >>> Thanks, >>> David Daney >> >> sure i will move these patches away from R6 and post them separately. > > I think using the ADDU macro is preferred here as it allows arbitrary > 32-bit values for `off', just like with memory references in MIPS assembly > instructions. > > Maciej > Hi, What ADDU macro? -- markos
