Module Name: src
Committed By: riastradh
Date: Thu May 9 22:38:29 UTC 2024
Modified Files:
src/tests/lib/libc/stdio: t_printf.c
Log Message:
tests/lib/libc/stdio/t_printf: Fix another rounding error.
Noted by kre.
This doesn't break a passing test or fix a failed test, at least on
x86 -- our printf produces `0x1.533p+3' for the double case and
`0xa.99ap+0' for the long double case. But of the hexadecimal number
literals that that start with 0x5 having three hexadigits to the
right of the fractional point, 0x5.4cdp+1 closest to the IEEE 754
binary64, VAX D, x86 extended precision, and IEEE 754 binary128
floating-point numbers closest to 10.6.
The reason is that the number 10.6 (or the nearest floating-point
number in any format with enough precision) is:
101.0100 1100 1100|1100... * 2^1 = 0x5.4cc|c...p+1
If we round at the vertical bar to the _nearest_ output with three
hexadigits of precision, the result is:
101.0100 1100 1101 * 2^1 = 0x5.4cdp+1
To generate a diff of this commit:
cvs rdiff -u -r1.15 -r1.16 src/tests/lib/libc/stdio/t_printf.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
