On Fri, Oct 23, 2015 at 02:56:26PM +0100, Mark Cave-Ayland wrote:
> From: Alexander Graf
>
> According to the ISA setting the Rc bit on mtspr is undefined behavior.
> Real 750 hardware simply ignores the bit and doesn't touch cr0 though.
>
> Unfortunately, Mac OS 9 relies on this fact and execu
On 23/10/15 15:56, Mark Cave-Ayland wrote:
> From: Alexander Graf
>
> According to the ISA setting the Rc bit on mtspr is undefined behavior.
> Real 750 hardware simply ignores the bit and doesn't touch cr0 though.
According to PowerISA 2.07, chapter 1.1.3:
"Reserved fields in instructions are
From: Alexander Graf
According to the ISA setting the Rc bit on mtspr is undefined behavior.
Real 750 hardware simply ignores the bit and doesn't touch cr0 though.
Unfortunately, Mac OS 9 relies on this fact and executes a few mtspr
instructions (to set XER for example) with Rc set.
So let's ha
