On 14.02.2011 19:12, Peter Maydell wrote:
> On 11 February 2011 15:10, <christophe.l...@st.com> wrote:
>> +uint32_t HELPER(neon_rshl_s32)(uint32_t valop, uint32_t shiftop)
>> +{
>> + int32_t dest;
>> + int32_t val = (int32_t)valop;
>> + int8_t shift = (int8_t)shiftop;
>> + if (shift >= 32) {
>> + dest = 0;
>> + } else if (shift < -32) {
>> + dest = val >> 31;
>
> This is the wrong answer: large rounding right shifts give zero.
>
>> + } else if (shift == -32) {
>> + dest = val >> 31;
>> + dest++;
>> + dest >>= 1;
>
> These three lines will always result in dest becoming
> 0 regardless of the input value.
>
You are right. Actually, I just intended to fix the case where
-32 < shift < 0, and merely re-instanciated the preceding macro with a known
size of 32.
You comments also apply to the 8 and 16 bits variants in that macro.
I am too respectful of existing code :-)
Christophe.
