Hi Anton,
On Thu, Jun 15, 2017 at 09:46:38AM +1000, Anton Blanchard wrote:
> The mcrf emulation code was looking at the CR fields in the reverse
> order. It also relied on reserved fields being zero which is somewhat
> fragile, so fix that too.
It masked out the reserved bits. I find the new code to be less
readable (but also more correct ;-) ). Maybe there should be (inline)
helper function to insert/extract CR fields?
Segher
> --- a/arch/powerpc/lib/sstep.c
> +++ b/arch/powerpc/lib/sstep.c
> @@ -683,8 +683,10 @@ int analyse_instr(struct instruction_op *op, struct
> pt_regs *regs,
> case 19:
> switch ((instr >> 1) & 0x3ff) {
> case 0: /* mcrf */
> - rd = (instr >> 21) & 0x1c;
> - ra = (instr >> 16) & 0x1c;
> + rd = 7 - ((instr >> 23) & 0x7);
> + ra = 7 - ((instr >> 18) & 0x7);
> + rd *= 4;
> + ra *= 4;
> val = (regs->ccr >> ra) & 0xf;
> regs->ccr = (regs->ccr & ~(0xfUL << rd)) | (val << rd);
> goto instr_done;
