[PATCH v4 16/16] powerpc sstep: Add support for prefixed fixed-point arithmetic

[Balamuruhan S]

On Fri, 2020-03-20 at 16:18 +1100, Jordan Niethe wrote:
> This adds emulation support for the following prefixed Fixed-Point
> Arithmetic instructions:
>   * Prefixed Add Immediate (paddi)
> 
> Signed-off-by: Jordan Niethe <jniethe5 at gmail.com>

Reviewed-by: Balamuruhan S <bala24 at linux.ibm.com>

> ---
> v3: Since we moved the prefixed loads/stores into the load/store switch
> statement it no longer makes sense to have paddi in there, so move it
> out.
> ---
>  arch/powerpc/lib/sstep.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
> index daef70eb8e22..6862fc019258 100644
> --- a/arch/powerpc/lib/sstep.c
> +++ b/arch/powerpc/lib/sstep.c
> @@ -1335,6 +1335,26 @@ int analyse_instr(struct instruction_op *op, const
> struct pt_regs *regs,
>  
>  	switch (opcode) {
>  #ifdef __powerpc64__
> +	case 1:
> +		prefix_r = word & (1ul << 20);
> +		ra = (suffix >> 16) & 0x1f;
> +		rd = (suffix >> 21) & 0x1f;
> +		op->reg = rd;
> +		op->val = regs->gpr[rd];
> +		suffixopcode = suffix >> 26;
> +		prefixtype = (word >> 24) & 0x3;
> +		switch (prefixtype) {
> +		case 2:
> +			if (prefix_r && ra)
> +				return 0;
> +			switch (suffixopcode) {
> +			case 14:	/* paddi */
> +				op->type = COMPUTE | PREFIXED;
> +				op->val = mlsd_8lsd_ea(word, suffix, regs);
> +				goto compute_done;
> +			}
> +		}
> +		break;
>  	case 2:		/* tdi */
>  		if (rd & trap_compare(regs->gpr[ra], (short) word))
>  			goto trap;