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Author Topic: Comparing bits in a register -  (Read 553 times) Bookmark and Share
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Xeda112358
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« on: 16 January, 2012, 04:51:37 »
0
I want to compare bit 5 to bit 1 and bit 4 to bit 0 in the A register (the other bits are always 0). in other words, I want to xor the two nibbles of A or something similar, but as fast as possible. To start, here is one idea:
Code: Select All | Copy To Clipboard

1
2
3
4
5
6
7
8
     ld c,a
     and $F0
     sla c
     sla c
     sla c
     sla c
     xor c
That is 47 cycles, 12 bytes-- too big/slow/inelegant for me to accept as the best method.
Logged


Grammer Download (2.29.04.12)
Latest update (possibly incomplete)
My pastebin
Spoiler for FileSyst:
FileSyst is an application that provides a folder and filesystem for the TI-83+/84+ calculators. It is designed to be easy to access and use in BASIC, and it can be used to access game files and save data, or to create a command prompt, among other things:

Spoiler for Graphiti:
This is a graph explorer for graph theory. It will require lots of work to finish. Currently you can:
Add/delete vertices
Add edges (direction not shown, but they are directed)
Arrange vertices in a circle (in the future, you will be able to define levels of rings and the number of nodes in each)
Create complete graphs quickly

Plans:
Add adjacency matrix viewer
Deleting edges
Multiple graphs support
Arrows for directed graphs
Planarity testing
Matrix operations
Weighted edges
Chromatic polynomials
Chromatic numbers

Spoiler for Stats:

Samocal             [o---------]
Virtual Processor   [o---------]
EnG                 [oo--------]
Grammer             [ooo-------]
AsmComp             [ooo-------]
Partex              [oooo------]
BatLib              [oooooooo--]
Grammer82           [----------]
Grammer68000        [----------]


Pseudonyms:  Zeda, Xeda, Thunderbolt
Languages:   English, français
Programming: z80 Assmebly
             Grammer
             TI-BASIC (83/84/+/SE, 89/89t/92)
Known For:   -Creator of the Grammer programming language
              (Winning program of zContest2011)
             -BatLib- One of the most feature packed libraries for BASIC programmers available
              with over 100 functions and a simple programming language
             -Learning to program z80 in hexadecimal before using an assembler (no computer was
              available!)
╔═╦╗░╠═╬╣▒║ ║║▓╚═╩╝█
Hot_Dog
If you can't find a cat, look for its tail.
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« Reply #1 on: 16 January, 2012, 05:00:46 »
+1
I don't quite understand how XORing will help you compare, but here's one (8 bytes, 31 cycles)

Code: Select All | Copy To Clipboard

1
2
3
4
5
6
7
8
9
10

  ld c, a
  rrca
  rrca
  rrca
  rrca
  xor c
  and $F0
Logged
There are people who can speak two languages, and they are called bilingual.  There are people who speak three languages and are therefore trilingual.  Then there are people who speak one language, and these people are called Americans.
Xeda112358
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« Reply #2 on: 16 January, 2012, 05:02:47 »
0
Thanks! I still wonder if there is some crazy method available, but that is a lot better!

I just want to check if they are the same or not. If not, the XOR (or in your case, the AND) will return nz whereas if they are the same, it will return z.
Logged


Grammer Download (2.29.04.12)
Latest update (possibly incomplete)
My pastebin
Spoiler for FileSyst:
FileSyst is an application that provides a folder and filesystem for the TI-83+/84+ calculators. It is designed to be easy to access and use in BASIC, and it can be used to access game files and save data, or to create a command prompt, among other things:

Spoiler for Graphiti:
This is a graph explorer for graph theory. It will require lots of work to finish. Currently you can:
Add/delete vertices
Add edges (direction not shown, but they are directed)
Arrange vertices in a circle (in the future, you will be able to define levels of rings and the number of nodes in each)
Create complete graphs quickly

Plans:
Add adjacency matrix viewer
Deleting edges
Multiple graphs support
Arrows for directed graphs
Planarity testing
Matrix operations
Weighted edges
Chromatic polynomials
Chromatic numbers

Spoiler for Stats:

Samocal             [o---------]
Virtual Processor   [o---------]
EnG                 [oo--------]
Grammer             [ooo-------]
AsmComp             [ooo-------]
Partex              [oooo------]
BatLib              [oooooooo--]
Grammer82           [----------]
Grammer68000        [----------]


Pseudonyms:  Zeda, Xeda, Thunderbolt
Languages:   English, français
Programming: z80 Assmebly
             Grammer
             TI-BASIC (83/84/+/SE, 89/89t/92)
Known For:   -Creator of the Grammer programming language
              (Winning program of zContest2011)
             -BatLib- One of the most feature packed libraries for BASIC programmers available
              with over 100 functions and a simple programming language
             -Learning to program z80 in hexadecimal before using an assembler (no computer was
              available!)
╔═╦╗░╠═╬╣▒║ ║║▓╚═╩╝█
Hot_Dog
If you can't find a cat, look for its tail.
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« Reply #3 on: 16 January, 2012, 05:05:17 »
0
So you want to know if bits 5, 4, 1 and 0 are all alike?
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There are people who can speak two languages, and they are called bilingual.  There are people who speak three languages and are therefore trilingual.  Then there are people who speak one language, and these people are called Americans.
Xeda112358
Xombie. I am it.
Coder Of Tomorrow
LV12 Extreme Poster (Next: 5000)
*
Offline Offline

Last Login: Today at 15:29:05
Date Registered: 31 October, 2010, 08:46:36
Location: Land of Little Cubes and Tea, NY
Posts: 3740


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Total Post Ratings: +598

View Profile
« Reply #4 on: 16 January, 2012, 05:06:47 »
0
I just want to know if bit 5 == bit 1 and bit 4 == bit 0.
Logged


Grammer Download (2.29.04.12)
Latest update (possibly incomplete)
My pastebin
Spoiler for FileSyst:
FileSyst is an application that provides a folder and filesystem for the TI-83+/84+ calculators. It is designed to be easy to access and use in BASIC, and it can be used to access game files and save data, or to create a command prompt, among other things:

Spoiler for Graphiti:
This is a graph explorer for graph theory. It will require lots of work to finish. Currently you can:
Add/delete vertices
Add edges (direction not shown, but they are directed)
Arrange vertices in a circle (in the future, you will be able to define levels of rings and the number of nodes in each)
Create complete graphs quickly

Plans:
Add adjacency matrix viewer
Deleting edges
Multiple graphs support
Arrows for directed graphs
Planarity testing
Matrix operations
Weighted edges
Chromatic polynomials
Chromatic numbers

Spoiler for Stats:

Samocal             [o---------]
Virtual Processor   [o---------]
EnG                 [oo--------]
Grammer             [ooo-------]
AsmComp             [ooo-------]
Partex              [oooo------]
BatLib              [oooooooo--]
Grammer82           [----------]
Grammer68000        [----------]


Pseudonyms:  Zeda, Xeda, Thunderbolt
Languages:   English, français
Programming: z80 Assmebly
             Grammer
             TI-BASIC (83/84/+/SE, 89/89t/92)
Known For:   -Creator of the Grammer programming language
              (Winning program of zContest2011)
             -BatLib- One of the most feature packed libraries for BASIC programmers available
              with over 100 functions and a simple programming language
             -Learning to program z80 in hexadecimal before using an assembler (no computer was
              available!)
╔═╦╗░╠═╬╣▒║ ║║▓╚═╩╝█
calc84maniac
Epic z80 roflpwner
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Posts: 2735


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« Reply #5 on: 16 January, 2012, 05:14:33 »
+3
and $00110011
jp po,bits_different
and $00010001
jp po,bits_different

If the other bits are already 0, you can go with this:
or a
jp po,bits_different
and $00010001
jp po,bits_different
Logged
"Most people ask, 'What does a thing do?' Hackers ask, 'What can I make it do?'" - Pablos Holman
Xeda112358
Xombie. I am it.
Coder Of Tomorrow
LV12 Extreme Poster (Next: 5000)
*
Offline Offline

Last Login: Today at 15:29:05
Date Registered: 31 October, 2010, 08:46:36
Location: Land of Little Cubes and Tea, NY
Posts: 3740


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Total Post Ratings: +598

View Profile
« Reply #6 on: 16 January, 2012, 05:16:04 »
0
For the second one, the OR A would not recognise if a was %00110000, right? But the first one looks a lot more beautiful, thanks!
Logged


Grammer Download (2.29.04.12)
Latest update (possibly incomplete)
My pastebin
Spoiler for FileSyst:
FileSyst is an application that provides a folder and filesystem for the TI-83+/84+ calculators. It is designed to be easy to access and use in BASIC, and it can be used to access game files and save data, or to create a command prompt, among other things:

Spoiler for Graphiti:
This is a graph explorer for graph theory. It will require lots of work to finish. Currently you can:
Add/delete vertices
Add edges (direction not shown, but they are directed)
Arrange vertices in a circle (in the future, you will be able to define levels of rings and the number of nodes in each)
Create complete graphs quickly

Plans:
Add adjacency matrix viewer
Deleting edges
Multiple graphs support
Arrows for directed graphs
Planarity testing
Matrix operations
Weighted edges
Chromatic polynomials
Chromatic numbers

Spoiler for Stats:

Samocal             [o---------]
Virtual Processor   [o---------]
EnG                 [oo--------]
Grammer             [ooo-------]
AsmComp             [ooo-------]
Partex              [oooo------]
BatLib              [oooooooo--]
Grammer82           [----------]
Grammer68000        [----------]


Pseudonyms:  Zeda, Xeda, Thunderbolt
Languages:   English, français
Programming: z80 Assmebly
             Grammer
             TI-BASIC (83/84/+/SE, 89/89t/92)
Known For:   -Creator of the Grammer programming language
              (Winning program of zContest2011)
             -BatLib- One of the most feature packed libraries for BASIC programmers available
              with over 100 functions and a simple programming language
             -Learning to program z80 in hexadecimal before using an assembler (no computer was
              available!)
╔═╦╗░╠═╬╣▒║ ║║▓╚═╩╝█
calc84maniac
Epic z80 roflpwner
Coder Of Tomorrow
LV11 Super Veteran (Next: 3000)
*
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Gender: Male
Last Login: 14 May, 2013, 10:02:35
Date Registered: 28 August, 2008, 05:09:05
Location: Right behind you.
Posts: 2735


Total Post Ratings: +373

View Profile
« Reply #7 on: 16 January, 2012, 05:17:52 »
+1
Quote from: Xeda112358 on 16 January, 2012, 05:16:04
For the second one, the OR A would not recognise if a was %00110000, right? But the first one looks a lot more beautiful, thanks!
The parity flag would be the same either way because it is based on the final result in A. That would indeed return PE, and go through to the second case where it returns PO.
Logged
"Most people ask, 'What does a thing do?' Hackers ask, 'What can I make it do?'" - Pablos Holman
Xeda112358
Xombie. I am it.
Coder Of Tomorrow
LV12 Extreme Poster (Next: 5000)
*
Offline Offline

Last Login: Today at 15:29:05
Date Registered: 31 October, 2010, 08:46:36
Location: Land of Little Cubes and Tea, NY
Posts: 3740


Topic starter
Total Post Ratings: +598

View Profile
« Reply #8 on: 16 January, 2012, 05:19:56 »
0
oh, right Big smile Thanks much, this is very nice!
Logged


Grammer Download (2.29.04.12)
Latest update (possibly incomplete)
My pastebin
Spoiler for FileSyst:
FileSyst is an application that provides a folder and filesystem for the TI-83+/84+ calculators. It is designed to be easy to access and use in BASIC, and it can be used to access game files and save data, or to create a command prompt, among other things:

Spoiler for Graphiti:
This is a graph explorer for graph theory. It will require lots of work to finish. Currently you can:
Add/delete vertices
Add edges (direction not shown, but they are directed)
Arrange vertices in a circle (in the future, you will be able to define levels of rings and the number of nodes in each)
Create complete graphs quickly

Plans:
Add adjacency matrix viewer
Deleting edges
Multiple graphs support
Arrows for directed graphs
Planarity testing
Matrix operations
Weighted edges
Chromatic polynomials
Chromatic numbers

Spoiler for Stats:

Samocal             [o---------]
Virtual Processor   [o---------]
EnG                 [oo--------]
Grammer             [ooo-------]
AsmComp             [ooo-------]
Partex              [oooo------]
BatLib              [oooooooo--]
Grammer82           [----------]
Grammer68000        [----------]


Pseudonyms:  Zeda, Xeda, Thunderbolt
Languages:   English, français
Programming: z80 Assmebly
             Grammer
             TI-BASIC (83/84/+/SE, 89/89t/92)
Known For:   -Creator of the Grammer programming language
              (Winning program of zContest2011)
             -BatLib- One of the most feature packed libraries for BASIC programmers available
              with over 100 functions and a simple programming language
             -Learning to program z80 in hexadecimal before using an assembler (no computer was
              available!)
╔═╦╗░╠═╬╣▒║ ║║▓╚═╩╝█
calc84maniac
Epic z80 roflpwner
Coder Of Tomorrow
LV11 Super Veteran (Next: 3000)
*
Offline Offline

Gender: Male
Last Login: 14 May, 2013, 10:02:35
Date Registered: 28 August, 2008, 05:09:05
Location: Right behind you.
Posts: 2735


Total Post Ratings: +373

View Profile
« Reply #9 on: 16 January, 2012, 05:24:29 »
+2
Hmm, and I guess Hot_Dog's method could be slightly improved by doing this (mainly a size optimization over mine because mine has an "early out")

  ld c, a
  rrca
  rrca
  rrca
  rrca
  xor c
  jr nz,bits_different
« Last Edit: 16 January, 2012, 05:24:42 by calc84maniac » Logged
"Most people ask, 'What does a thing do?' Hackers ask, 'What can I make it do?'" - Pablos Holman
Xeda112358
Xombie. I am it.
Coder Of Tomorrow
LV12 Extreme Poster (Next: 5000)
*
Offline Offline

Last Login: Today at 15:29:05
Date Registered: 31 October, 2010, 08:46:36
Location: Land of Little Cubes and Tea, NY
Posts: 3740


Topic starter
Total Post Ratings: +598

View Profile
« Reply #10 on: 16 January, 2012, 05:26:23 »
0
So that is slightly slower, but I see how that works! These are great, thanks much, guys!
Logged


Grammer Download (2.29.04.12)
Latest update (possibly incomplete)
My pastebin
Spoiler for FileSyst:
FileSyst is an application that provides a folder and filesystem for the TI-83+/84+ calculators. It is designed to be easy to access and use in BASIC, and it can be used to access game files and save data, or to create a command prompt, among other things:

Spoiler for Graphiti:
This is a graph explorer for graph theory. It will require lots of work to finish. Currently you can:
Add/delete vertices
Add edges (direction not shown, but they are directed)
Arrange vertices in a circle (in the future, you will be able to define levels of rings and the number of nodes in each)
Create complete graphs quickly

Plans:
Add adjacency matrix viewer
Deleting edges
Multiple graphs support
Arrows for directed graphs
Planarity testing
Matrix operations
Weighted edges
Chromatic polynomials
Chromatic numbers

Spoiler for Stats:

Samocal             [o---------]
Virtual Processor   [o---------]
EnG                 [oo--------]
Grammer             [ooo-------]
AsmComp             [ooo-------]
Partex              [oooo------]
BatLib              [oooooooo--]
Grammer82           [----------]
Grammer68000        [----------]


Pseudonyms:  Zeda, Xeda, Thunderbolt
Languages:   English, français
Programming: z80 Assmebly
             Grammer
             TI-BASIC (83/84/+/SE, 89/89t/92)
Known For:   -Creator of the Grammer programming language
              (Winning program of zContest2011)
             -BatLib- One of the most feature packed libraries for BASIC programmers available
              with over 100 functions and a simple programming language
             -Learning to program z80 in hexadecimal before using an assembler (no computer was
              available!)
╔═╦╗░╠═╬╣▒║ ║║▓╚═╩╝█
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