HP-15C CE woes: 1 bug, 2 limitations, 3 questions

[J-F Garnier]

(08-09-2023 03:42 AM)brouhaha Wrote:  Unfortunately it appears that the decimal display conversion in the 16C does do exactly that.

The word-wide parallel BCD addition involves an intermediate result to which is added 0x66666666666666. If a digit going into that is 0xA through 0xD, a carry correction will occur.

However, if a digit is 0xE or 0xF, then effectively there are two (decimal) carries, and the parallel addition algorithm doesn't handle that, losing one of the carries.

Perfect diagnostic, I didn't get it.

The pre-release 15C+ had exactly that problem, and it was fixed in the LE.
Carefully read this old 2012 message:
thread-210530-post-210733

Strange how people involved in the 15C+ (I wasn't) didn't remember that :-)
The forum archives are our memory.

J-F