GCC for the TMS9900 (new thread)

[+jedimatt42]

Doing some searching, I've found this already discussed... concluding that the examples on Theory's page are incorrect.. https://forums.atariage.com/topic/164295-gcc-for-the-ti/page/31/#comment-5295072

 

 

And I have more reading to do. There was also discussion back here: https://forums.atariage.com/topic/164295-gcc-for-the-ti/page/35/#comment-5363142

 

And Lee's fbForth Appendix L Notes on Radix-100 Notation should get me through. 

 

[+Lee Stewart]

10 hours ago, jedimatt42 said:

Or, is Thierry's data wrong?

 

Most of the examples on Thierry’s page are, indeed, wrong. Here are the corrected examples:

Exponent Mantissa                     Value                Comment
-------- ---------------------------  -------------------  ------------------
>40      >01 >02 >03 >04 >05 >06 >07    1.020304050607     correct
>41      >01 >02 >03 >04 >05 >06 >0B   10.20304050611      102.0304050611
>3F      >05 >00 >00 >00 >00 >00 >00    0.5                  0.05
>BF(-41) >FF >02 >03 >05 >05 >06 >12  -10.20304050618       -1.020305050618
>00      >00 >xx >xx >xx >xx >xx >xx    0 (any exponent!)  correct

 

Also, though -41 is certainly correct for >BF, it is misleading. The hexadecimal representation of the absolute value of the entire number is

>4001 >0203 >0505 >0612

 

To represent a negative number, only the first word is negated. The negation is merely a contrivance to indicate that the number is negative. For math operations, the negation is noted (saved) and undone, i.e., operations are only performed on absolute values, adjusting the sign at the end.

 

...lee

[+Lee Stewart]

4 hours ago, jedimatt42 said:

Doing some searching, I've found this already discussed... concluding that the examples on Thierry's page are incorrect.. https://forums.atariage.com/topic/164295-gcc-for-the-ti/page/31/#comment-5295072

 

And I have more reading to do. There was also discussion back here: https://forums.atariage.com/topic/164295-gcc-for-the-ti/page/35/#comment-5363142

 

And Lee's fbForth Appendix L Notes on Radix-100 Notation should get me through. 

 

Also referenced here followed by a correction here. [Tried to find these references before my little dissertation above!]

 

...lee

[+MarkB]

If anyone finds a bug and wants to report it, there is a bug tracker here https://github.com/mburkley/tms9900-gcc/issues

Please include a small sample of code that reproduces the problem and also which version of the patch you are using (1.31 etc)

Thanks

Mark