LZ-Adv: Ti-ROM math functions

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LZ-Adv: Ti-ROM math functions

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I have attached the info on the math functions to this letter.
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-- 
_______________________________________


Dines Justesen
Email: dines@post1.com or
       c958362@student.dtu.dk
WWW  : http://www.gbar.dtu.dk/~c958362/
_______________________________________


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In TI-RAM 827C is called buffer for name of last error. This is not the
whole truth, the buffer is also used for other prupose by the function
which handles errors. I have not seen it used other places, but i might be
used as more general buffer. Based on the functions i have seen my guess is
that the buffer is 80h bytes long, since this is the largest value i have
seen used.


The following function is called when an error happens.


--- Call 0A87 --- Error handler -------------------------------------------
Input : A holds number of error which has occured


Result : The standard error screen is displayed with the number of the
         error and a string telling what it means. This functions uses alot
         of memory adresses to determine what happens besides this.


When an error occurs a lot of memory adresses which we do not know the
function of is used to determine what happens, but it is possible to call
it from zshell without setting any of these. I have checked what happens
and as far as i can see, the adresses is used to determine if you can goto
the place the error happens, how much temperary memory was used and stuff
like that.


Before the the function there is a table of functions setting the value in
a and then calling this functions. Below is a list of the functions.


ERROR    ADR
-------------
14	 0A59
15	 0A5D
0F	 0A45 *
22	 0A85
81	 0A08
82	 0A0C
83	 0A10
84	 0A14
85	 0A18
86	 0A61
87	 0A1C
88       0A20
89	 0A24
8A	 0A28
8B	 0A2C
8C	 0A30
8D	 0A34
8E	 0A38
8F	 0A3C
90	 0A49
91	 0A4D
92	 0A51
93	 0A55
97	 0A65
98	 0A69
99	 0A6D
9C	 0A71
9D	 0A75
9E	 0A79
A0	 0A7D
A1	 0A81


* This function will only generate an error if bit 2 of iy+13 is 1.


If you want to see how the error is written on the display have a look at
page 7 adress 4784 (this function was first documented by Rob Taylor).


I have found a tabel of constants in the ROM, the constants can be loaded
into a register with the following function. The table starts at 24E6.


--- Call 24D3 --- Get constant -------------------------------------------
Input : A holds the number of canstant to get (max 6)


Result : OP2 holds the constant.


The constants are the following:
#        Value             Name
--------------------------------
0: 57.29577951308232       180/Pi
1:  1.570796326794897      Pi/2
2:  0.7853981633974483     Pi/4
3:  0.4342944816032518     Log e
4:  3.141592653589800      Pi
5:  0.01745329251994330    Pi/180
6:  2.302585092994046      ln 10


The following functions is math functions which operates on the registers.
Some of the functions uses bit 6 of iy+E to decide if the last two digits of
the registers, should be used.
--------------------------------------------------------------------------
10E2 / 10EE OP1=sqrt(OP1) ??
1010        OP1=OP1/OP2 ?
1016        OP1=1/OP1
0D68        OP1=OP1-OP2
0D65        OP1=OP1-1
0D60        OP1=OP1+1
0D5D        OP1=2*OP1
0D54 / 0D4F OP1=OP2-OP1
0D36        OP1=|OP1|+|OP2|
0D31        OP1=OP1+(HL)
0D22        OP1=MAX(OP1,OP2)
0D13        OP1=MIN(OP1,OP2)
0D6F / 0D78 OP1=OP1+OP2
0E59        OP1=OP1*OP2 (OP3 destroyed)
0E32        OP1 is converted from radians to deg. (OP2,3 destroyed)
0E3B        OP1 is converted from deg to radians. (OP2,3 destroyed)
0E44        OP1=OP1^3   (OP2,3 destroyed)
0E49        OP1=OP1*0.5 (OP2,3 destroyed)
0E51        OP1=OP1^2   (OP2,3 destroyed)
0F92        OP1=-OP1


All the functions above is all documented by TI on the TI83, except two
function, but these have been checked and they are there. Some of the func-
tions documented on the TI83 have not been found yet, they are there but
they are hard to find.
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