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Messages - Xeda112358
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271
« on: November 09, 2018, 09:39:43 am »
Pretty much the only difference in the BASIC language is no real graphics functions on the nspire. The rest is pretty much the same.
272
« on: November 08, 2018, 09:53:07 pm »
Thanks for weighing in, Stefan, you are probably one of the most knowledgeable 68k/nSpire BASIC programmers here, so you'd really know what was feasible ^_^ And the link looks pretty useful.
273
« on: November 08, 2018, 09:49:11 am »
I have been cleaning up code and doing some optimizations and modifications. I probably broke something, but I wanted a backup. Updates:- I cleaned up the source a bit.
- Going with the previous update, without the jumptable I had so e unused routines (intended for Grammer Assembly programs) that I removed
- I implemented some custom VAT traversal routines. The OS routines were incredibly slow and I needed an excuse to use my VAT sort code
 - Added in code to throw an error if a Grammer Assembly program is run.
- Version number is going to be sensible now, starting at 2.50.0.0
- Minor optimizations.
Features I want: - with a sorted VAT, I can speed up the look-up of OS variables.
- I want a scrollable start menu
274
« on: November 04, 2018, 01:36:27 pm »
Then the next part is to train a neural network to generate an image based on those attributes !
Ijust recently started playing Pathfinder and my first thought was how useful a calc program could be for this.
275
« on: November 04, 2018, 10:56:56 am »
So, fun fact: floating point numbers can be changed to a variable reference instead, kind of like a shortcut on your computer, and the OS doesn't verify it. In assembly, when you are looking for a variable, you put a name in OP1 and use FindSym or ChkFindSym. Those names are 9 bytes, which is also the size of a float (not a coincidence-- it's part of why names are limited to 8 bytes). You can actually change the contents of a Real variable to such a name, and when you try to read it's value, it will instead return the value of the variable it points to. For example, change the bytes of the Real variable, A, from 008000000000000000 (the number 0) to 015D01000000000000 and when you read A, it will return the contents of L2. Or, since lists are just stored as a bunch of Real (or Complex) numbers, you can modify elements of the list to be pointers. In this way, you could read Str1, Str2, Str3,..., Str0 by reading an element of L1, which could be useful, occasionally Some things to note: You can't modify the contents of the original variable in this way. If A points to Str2, then "33"+A→A does not modify Str2. However, "33"+A will work like "33"+Str2. Storing the names of programs and appvars and whatnot isn't useful.
Attached is a program that turns L1 into a 4-element list {L2,[A],Str1,L1}. Here is the source. You need to delete L1 first, my code wasn't reliably deleting it. #define bcall(x) rst 28h \ .dw x
rMOV9TOOP1 = 20h
_ChkFindSym = 42F1h
_CreateRList= 4315h
.db $BB,$6D
.org $9D95
ld hl,name
rst rMOV9TOOP1
bcall(_ChkFindSym)
ret c
ld hl,name
rst rMOV9TOOP1
ld hl,4
bcall(_CreateRList)
inc de
inc de
ld hl,data
ld bc,31
ldir
ret
data:
.db 1,$5D,1,0,0,0,0,0,0
.db 2,$5C,0,0,0,0,0,0,0
.db 4,$AA,0,0,0,0,0,0,0
name:
.db 1,$5D,0,0
276
« on: November 02, 2018, 01:30:43 am »
Probably, though it would take some effort. Most instruction can use literal replacements, but labels and macros need some more advanced treatment.
277
« on: November 01, 2018, 10:53:28 pm »
I asked a little while ago, and as far as I know it doesn't exist yet.
278
« on: October 29, 2018, 07:39:23 pm »
Your computation of f(x+1) is correct, but then you need to subtract f(x), so:
##
\begin{aligned}
f(x+1)-f(x)&=(x^{3}-x+3)-(x^{3}-3x^{2}+2x+3),\\
&=x^{3}-x+3-x^{3}+3x^{2}-2x-3,\\
&=-3x+3x^{2},\\
&=3x^{2}-3x.\\
\end{aligned}
##
279
« on: October 29, 2018, 02:04:57 pm »
It is basically 3+2(x+1)-3(x+1)2+(x+1)3-(3+2x-3x2+x3) which should be 3x^2-3x (I hope).
280
« on: October 29, 2018, 10:58:21 am »
Try without the brackets. The way you are doing it is actually taking the data at Y0 as an address, but you want to use Y0 itself as an address.
281
« on: October 29, 2018, 09:27:07 am »
For what it's worth, I did get it to work in TI-BASIC. My program only worked up to degree 8 polynomials (I could extend it; it was just a convenient size).
I'm on mobile atm and AFC, so I'll try to describe my code:
What I did is I computed Y1(Xmin+K∆X), for k from 0 to 8, storing them to a list, then I recombined starting from the end (the last element is a function of all previous elements and itself) applying that sum.
Then for efficiency, I clipped off any trailing zeros in L1.
I started plotting from Xmin to Xmax with step of ∆X:
For(X,Xmin,Xmax,∆X
Pt-On(X,L1(1
For(K,1,N-1
L1(K)+L1(K+1→L1(K
End
End
Note that it doesn't work well for non-polynomials like sine and cosine, but it can do rough estimates. I'm also sure it would fail at poles.
282
« on: October 28, 2018, 10:32:12 pm »
Hi folks, I wanted to share a technique I came up with for evaluating sequential points of a polynomial, which is especially useful when you are drawing them. A naive approach would be evaluate the whole polynomial at each point, but the method I'll show you allows you to evaluate at a few points, and then for each subsequent point just use additions.
The basic premise is to use ##f(x)## as a starting point to get to ##f(x+1)##. For example, take ##f(x)=3+2x##. To get to ##f(x+1)##, all you have to do is add 2. Things get more complicated as you go to higher degree polynomials. For example, take ##f(x)=3+2x-3x^{2}+x^{3}##. Then to get to ##f(x+1)##, you need to add ##3x^{2}-3x##. However, you can go even further by finding how to get from ##3x^{2}-3x## to ##3(x+1)^{2}-3(x+1)##.
Now comes the theory.
Take ##f_{1}(x)=f(x+1)-f(x)## and ##f_{n+1}(x)=f_{n}(x+1)-f_{n}(x)##.
Then ##f(x+1)=f(x)+f_{1}(x)## and ##f_{n}(x+1)=f_{n}(x)+f_{n+1}(x)##.
##\begin{aligned}
f_{2}(x) &=f_{1}(x+1)-f_{1}(x),\\
&=(f(x+2)-f(x+1))-(f(x+1)-f(x)),\\
&=f(x+2)-2f(x+1)+f(x).
\end{aligned}##
##\begin{aligned}
f_{3}(x)&=f_{2}(x+1)-f_{2}(x),\\
&=(f(x+3)-2f(x+2)+f(x+1))-(f(x+2)-2f(x+1)+f(x)),\\
&=f(x+3)-3f(x+2)+3f(x+1))-f(x).
\end{aligned}##
And in general,
##f_{n}(x)=\sum_{k=0}^{n}{{n\choose k}(-1)^{k}f(x+n-k)}##
If you set ##x=0##:
##f_{n}(0)=\sum_{k=0}^{n}{{n\choose k}(-1)^{k}f(n-k)}##
So now let's take again, ##f(x)=3+2x-3x^{2}+x^{3}##.
##\begin{aligned}
f(0)&=3,\\
f_{1}(0)&=f(1)-f(0)&=0,\\
f_{2}(0)&=f(2)-2f(1)+f(0)&=0,\\
f_{3}(0)&=f(3)-3f(2)+3f(1)-f(0)&=6,\\
f_{k>3}(0)&=0.\\
\end{aligned}##
So what these values allow us to do, ##{3,0,0,6}##, is use a chain of additions to get the next value, instead of evaluating the cubic polynomial at each x:
##\begin{array}{rrrr}
[&3,&0,&0,&6]\\
[&3,&0,&6,&6]\\
[&3,&6,&12,&6]\\
[&9,&18,&18,&6]\\
[&27,&36,&24,&6]\\
[&63,&60,&30,&6]\\
[&123,&90,&36,&6]\\
[&213,&126,&42,&6]\\
...
\end{array}##
Basically, add the second element to the first, third element to the second, and fourth element to the third. The new value is the first. Repeat. So the next iteration would yield [213+126,126+42,42+6,6]=[339,168,48,6], and indeed, f(8)=339.
I'd like to apologise for how garbled this is, I'm really tired.
Also, you should note that for an n-th degree polynomial, you need to compute up to ##f_{n}(x)##, but everything after that is 0.
283
« on: October 17, 2018, 05:17:51 pm »
Earlier in the thread it is stated that some games just can't fit in the non-SE calcs. The Pokemon games are among those, so you are out of luck.
284
« on: October 16, 2018, 06:49:23 pm »
Wow, that's pretty cool!
285
« on: October 16, 2018, 06:33:14 pm »
Here is a decent arctangent routine that works on [0,1), so you'll have to do the work to extend it outside that range. It uses a small lookup table and linear interpolation. atan8:
;computes 256*atan(A/256)->A
;56 bytes including the LUT
;min: 246cc
;max: 271cc
;avg: 258.5cc
rlca
rlca
rlca
ld d,a
and 7
ld hl,atan8LUT
add a,l
ld l,a
#if (atan8LUT&255)>248 ;this section not included in size/speed totals
jr nc,$+3 ;can add three bytes, 12cc to max, 11cc to min, and 11.5cc to avg
inc h
#endif
ld c,(hl)
inc hl
ld a,(hl)
sub c
ld e,0
ex de,hl
ld d,l
ld e,a
sla h \ jr nc,$+3 \ ld l,e
add hl,hl \ jr nc,$+3 \ add hl,de
add hl,hl \ jr nc,$+3 \ add hl,de
add hl,hl \ jr nc,$+3 \ add hl,de
add hl,hl \ jr nc,$+3 \ add hl,de
add hl,hl
add hl,hl
add hl,hl
; add hl,hl ;used in rounding...
ld a,h
; rra ;but doesn't seem to improve the error
adc a,c
ret
atan8LUT:
.db 0,32,63,92,119,143,165,184,201
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