On 28 July 2014 23:32, Aurelien Jarno <aurel...@aurel32.net> wrote: > On Mon, Jul 28, 2014 at 11:01:02PM +0100, Peter Maydell wrote: >> This may be true, but the TCG README doesn't define negative >> lengths as being "unspecified behaviour" (ie guaranteed to at >> least not crash even if the result isn't specified), and in fact the >> implementation of tcg_gen_deposit will assert on negative lengths. >> We shouldn't implement guest unpredictable cases as "crash QEMU". > > Well I tried this code under QEMU, and it clearly doesn't crash. It > seems the assert are not enabled with the default configuration options.
Try --enable-debug... > That said I agree it's something to avoid, but I don't think triggering > a RI exception is the thing to do (even if it is correct according the > MIPS ISA manual) when real silicon output a random result instead. Yes, you could emit code to do that instead if you like. thanks -- PMM
