Chuang-Yu Cheng 54afc2e7a5 printf: Fix floating-point rounding consistency for RTZ devices (#2202) ...

1. In vector test, prepare RTZ answer for RTZ rounding.

2. In mixed_format_random test, for a given float 'arg', the test
previously used 'arg' directly to generate ref_str:
   ```
     ref_str << str_sprintf(format, arg);
   ```

   This approach incorrectly assumes:
   ```
     (float) arg == to_fp(to_str(arg));
   ```

   However, this assumption fails under RTZ rounding. For example: 
   ```
     arg = 0xC642549C 
     to_str(arg) = -12437.152343f 
     to_fp_rtz(-12437.152343f) = 0xC642549B (-0X1.84A936P+13) 
     to_fp_rte(-12437.152343f) = 0xC642549C (-0X1.84A938P+13)
   ```

To address this, the reference result is now computed based on the
literal float string rather than the original 'arg' value.

2025-02-11 08:46:23 -08:00

43 KiB

Raw Blame History

View Raw