Re: [Qemu-devel] [PATCH] target-mips: fix mipsdsp_trunc16_sat16_round

[Petar Jovanovic]

________________________________________
From: Richard Henderson address@hidden on behalf of Richard Henderson 
address@hidden
Sent: Thursday, June 27, 2013 8:20 PM
To: Petar Jovanovic
Cc: Petar Jovanovic; address@hidden; address@hidden
Subject: Re: [Qemu-devel] [PATCH] target-mips: fix mipsdsp_trunc16_sat16_round

On 06/17/2013 03:39 PM, Petar Jovanovic wrote:
> -    int64_t temp;
> -
> -    temp = (int32_t)a + 0x00008000;
> +    uint16_t temp;
>
> -    if (a > (int)0x7fff8000) {
> -        temp = 0x7FFFFFFF;
> +    if (a > 0x7FFF7FFF) {
> +        temp = 0x7FFF;
>          set_DSPControl_overflow_flag(1, 22, env);
> +    } else {
> +        temp = ((a + 0x8000) >> 16) & 0xFFFF;

> This doesn't look right either, as it doesn't properly check for overflow of
> negative values.

What overflow of negative values?
Can you please list the values for which the result would not be correct?

Thanks.

Petar