On Mai 07 2025, Richard Henderson wrote:
> + /* Convert the 3 digit decimal exponent to binary. */
> + exp = ((hi >> 24) & 0xf)
> + + ((hi >> 20) & 0xf) * 10
> + + ((hi >> 16) & 0xf) * 100;
This is backwards. An exponent of 123 is stored as 0x01230000, not
0x03210000.
> + for (int i = 24; exp10; i -= 4, exp10 /= 10) {
> + res_hi |= (exp10 % 10) << i;
Again, this is backwards. Also, the decimal exponent of an extended
precision number can be as big as 4951. From the fpsp040:
| A15. Convert the exponent to bcd.
| As in A14 above, the exp is converted to bcd and the
| digits are stored in the final string.
|
| Digits are stored in L_SCR1(a6) on return from BINDEC as:
|
| 32 16 15 0
| -----------------------------------------
| | 0 | e3 | e2 | e1 | e4 | X | X | X |
| -----------------------------------------
That is, the fourth digit of the exponent is stored in the upper 4 bits
of the padding (OPERR is set if e4 is non-zero).
--
Andreas Schwab, sch...@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
