Bug in MATH ROM of the TI95

03082023, 07:46 PM
(This post was last modified: 03082023 11:08 PM by Namir.)
Post: #1




Bug in MATH ROM of the TI95
I have been tinkering with the TI95 and its MATH and STAT ROMs. I discovered that the Newtons Root method (option NTN in option ZRO) has a bug that causes the solution FOR ANY FUNCTION to jump to huge numbers and then overflow. I tested my fx(x)=exp(x)3*x^2 and fx(x)=x^25*x+6 functions and both bombed out. I inserted a pause (PAU) command in my function code to trace the values used by NTN and found that it does the following:
1) Evaluate fx at you initial guess (call it X). 2) Evaluate fx at X plus a small increment. 3) Evaluate fx at X minus a small increment. 4) Evaluate fx at a large number. 5) Repeat step 4 with different large numbers until the calculations overflow. I also noticed that the TI95 emulator by HrastProgrammer has the same bug in his port of the MATH ROM! I guess his ported the binary image of the MATH ROM. Anyone else out there has seen this bug? The Bisection method in the MATH ROM works fine! Namir 

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Messages In This Thread 
Bug in MATH ROM of the TI95  Namir  03082023 07:46 PM
RE: Bug in MATH ROM of the TI95  Dave Britten  03092023, 02:57 PM
RE: Bug in MATH ROM of the TI95  Thomas Klemm  03092023, 06:30 PM
RE: Bug in MATH ROM of the TI95  Namir  03102023, 12:16 PM
RE: Bug in MATH ROM of the TI95  Thomas Klemm  03102023, 01:13 PM
RE: Bug in MATH ROM of the TI95  Namir  03102023, 02:07 PM

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