I'd like to use the BR (branch on integer register) instruction in 32-bit user-space code on sparc64. The problem is that BR interprets the entire 64-bit contents of the register, which depending on how the value was produced may or may not do the right thing in 32-bit code. My main question is: what does the kernel do to the high 32 bits of the 64-bit integer registers during context switches? Does it a) preserve all 64 bits, b) clear the high halves (truncate to 32 bits), or c) insert unpredictable junk? I can handle a) and b), but c) means that I cannot ever safely use BR in 32-bit userspace. Also, does anyone know what Solaris does to the high 32 bits during context switches? /Mikael - To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
