Re: [ping][patch] Fixed-point patch 2/10

[Nigel Stephens <nigel@mips.com>]

Mark Mitchell wrote:
> Fu, Chao-Ying wrote:
>
>   
>> Ex 2: (A and B are negative. )
>> A.high = 0xffffffffffffffff and A.low = 0x8000000000000000
>> B.high = 0xffffffffffffffff and B.low = 0x0000000000000001
>> => A > B, 
>> because A.high == B.high and
>> (unsigned HOST_WIDE_INT) a.low > (unsigned HOST_WIDE_INT) b.low
>>     
>
> Yes, I see; two's complement is set up so that after masking the sign
> bit, you can do an unsigned compare.  Thank you for explaining.
>   

Since double_int is already declared with low unsigned, like this:

    typedef struct
    {
      unsigned HOST_WIDE_INT low;
      HOST_WIDE_INT high;
    } double_int;


Would it be more obvious to simply remove the casts altogether, e.g.

    double_int_scmp (double_int a, double_int b)
    {
      if (a.high < b.high)
        return -1;
      if (a.high > b.high)
        return 1;
      if (a.low < b.low)
        return -1;
      if (a.low > b.low)
        return 1;

      return 0;
    }



Nigel