Macros

[+Random Terrain]

Short term workaround...

 

  macro set_hi_nibble
asm
  lda {1}
  and #$0f
  sta {1}
  lda {2}
  asl
  asl
  asl
  asl
  ora {1}
  sta {1}
end
end

It works! If it's OK with you and SeaGtGruff, I'll use this on the bB page instead of the other thing.

[RevEng]

It's fine by me, though it should probably be replaced by my first suggestion (that didn't work) if the power-of-two thing is fixed.

 

I'll report it in the bug thread later today.

 

You might also want to make a note on your bB page that you can't use any commands that use a library inside a macro, within a bankswitched game. (pf* commands, multiplying by numbers that aren't powers of two, etc.)

[+Random Terrain]

You might also want to make a note on your bB page that you can't use any commands that use a library inside a macro, within a bankswitched game. (pf* commands, multiplying by numbers that aren't powers of two, etc.)

OK, thanks. I'll do that later this afternoon when I get back. Sure is nice to get this fixed so quickly. Now I can get back to working on my program.

[bogax]

I'm getting lost.

 

Here's an excerpt of the code from:

 

http://www.randomterrain.com/atari-2600-memories-batari-basic-commands.html#nybblemethis

 

 

  rem  ****************************************************************
  rem  *  Reusable macros for nybble variables. 
  rem  *

  macro set_lo_nibble
  {1}={1}&$F0
  {1}={1}|({2}&$0F)
end

  macro set_hi_nibble
asm
  lda {1}
  and #$0f
  sta {1}
  lda {2}
  asl
  asl
  asl
  asl
  ora {1}
  sta {1}
end
end


  rem  ****************************************************************
  rem  *  One variable is split into two thanks to 
  rem  *  macro and def.
  rem  *

  def PEEK_Game_Level=a&$0F
  def POKE_Game_Level=callmacro set_lo_nibble a

  def PEEK_Hit_Points=a/16
  def POKE_Hit_Points=callmacro set_hi_nibble a

 

That looks to me like set_lo_nibble and set_hi_nibble both want

two parameters and are both only being passed one,

am I missing something?

 

 

If you use exclusive or to swap in nibbles

you'll only get the bit's you mask for,

So I'd (re)write RevEng's code like this:

 

  macro set_hi_nibble
asm
  lda {2}
  asl
  asl
  asl
  asl
  eor {1}
  and #$F0
  eor {1}
  sta {1}
end
end

 

It might even be possible to write something that

swapped different nibbles depending on a parameter

(I haven't tryed, didn't seem worth it)

 

 

I haven't figured out when and where bBasic will choke

on complex expressions.

If bBasic fails to recognize powers of 2 greaer than 3,

would something like this work (again using an xor swap)

 

(1)=(2)*4*4^(1)&$F0^(1)

 

(I don't know how many parentheses you'd have to stick in

there to get the order of execution right or if that would

make bBasic choke)

Edited September 27, 2010 by bogax

[+Random Terrain]

I'm getting lost.

If you just want to use the nybble variables, you don't need to know the details.

 

Here's a simple example that just gives a nybble variable the value of five:

 

POKE_My_Variable 5

 

 

Here's an example that increases it by one:

 

temp5 = (PEEK_My_Variable) + 1 : POKE_My_Variable temp5

 

 

POKE and PEEK is all you have to know.

Edited September 27, 2010 by Random Terrain

[bogax]

 

Here's a simple example that just gives a nybble variable the value of five:

 

POKE_My_Variable 5

 

Oh, OK, I get it

 

def is a simple substitution so that that expands to something like:

 

callmacro set_lo_nibble a 5

 

The def statement supplies the first parameter and you supply the

second where you invoke the def'd name.

[bogax]

Finally installed bB

 

macro set_hi_nibble
{1}=(({2}*4*4^{1})&$F0)^{1}
end

 

Compiles just as one would hope

 

.L00 ;  macro set_hi_nibble

MAC set_hi_nibble

.L01 ;  {1} =  (  ( {2} * 4 * 4 ^ {1} )  & $F0 )  ^ {1}

; complex statement detected
LDA {2}
asl
asl
asl
asl
EOR {1}
AND #$F0
EOR {1}
STA {1}
ENDM

[SeaGtGruff]

  macro set_hi_nibble
  {1}=(({2}*4*4^{1})&$F0)^{1}
end

Holy crap, that's awesome! So the new-and-improved macros and defs would look like this:

 

  macro set_lo_nibble
  {1}=(({2}^{1})&$0F)^{1}
end

  macro set_hi_nibble
  {1}=(({2}*4*4^{1})&$F0)^{1}
end

  def PEEK_game_level=a&$0F
  def POKE_game_level=callmacro set_lo_nibble a

  def PEEK_hit_points=a/4/4
  def POKE_hit_points=callmacro set_hi_nibble a

No need to include div_mul.asm, and it automatically keeps the POKEs within the legal values of 0 to 15!

 

Thanks, bogax!

 

RT, you'd better update your page!

 

Michael

 

 

 

[SeaGtGruff]

Here's a slight revision to the defs that use dims for the variable names-- in case it's easier than remembering which letters to use:

 

  macro set_lo_nibble
  {1}=(({2}^{1})&$0F)^{1}
end

  macro set_hi_nibble
  {1}=(({2}*4*4^{1})&$F0)^{1}
end

  dim game_level=a
  dim hit_points=a
  dim moose_tracks=b
  dim rabbit_ears=b
  dim saucer_speed=c
  dim something_else=c

  def PEEK_game_level=game_level&$0F
  def POKE_game_level=callmacro set_lo_nibble game_level

  def PEEK_hit_points=hit_points/4/4
  def POKE_hit_points=callmacro set_hi_nibble hit_points

  def PEEK_moose_tracks=moose_tracks&$0F
  def POKE_moose_tracks=callmacro set_lo_nibble moose_tracks

  def PEEK_rabbit_ears=rabbit_ears/4/4
  def POKE_rabbit_ears=callmacro set_hi_nibble rabbit_ears

  def PEEK_saucer_speed=saucer_speed&$0F
  def POKE_saucer_speed=callmacro set_lo_nibble saucer_speed

  def PEEK_something_else=something_else/4/4
  def POKE_something_else=callmacro set_hi_nibble something_else

Of course, you still need to remember whether a given nibble variable uses the lo nibble or the hi nibble, and use the correct defs for that type of nibble variable.

 

For a lo nibble variable:

 

dim lonibblevariable=x

def PEEK_lonibblevariable=lonibblevariable&$0F

def POKE_lonibblevariable=callmacro set_lo_nibble lonibblevariable

 

For a hi nibble variable:

 

dim hinibblevariable=y

def PEEK_hinibblevariable=hinibblevariable/4/4

def POKE_hinibblevariable=callmacro set_hi_nibble hinibblevariable

 

Michael

Edited September 28, 2010 by SeaGtGruff

[+Random Terrain]

See if this looks OK:

 

http://www.randomterrain.com/atari-2600-memories-batari-basic-commands.html#nybblemacrodef

 

 

Thanks.

[SeaGtGruff]

See if this looks OK:

I didn't scrutinize it in slow motion with a magnifying glass, but it looked okay when I gave it a quick read.

 

Michael

[bogax]

See if this looks OK:

 

http://www.randomterrain.com/atari-2600-memories-batari-basic-commands.html#nybblemacrodef

 

 

Thanks.

 

It might be worth pointing out that there's a reason

for using eg *4*4 instead of *16

[+Random Terrain]

It might be worth pointing out that there's a reason

for using eg *4*4 instead of *16

Thanks. It's because 4 looks like a pretty sail on a sailboat, right?

[STGraves]

Ok, which is the one to be used to call the variable "a" on the code in this example

 

def PEEK_Game_Level=a&$0F

def POKE_Game_Level=callmacro set_lo_nibble a

 

Peek or poke?

Or can I call directly _Game_Level on the code?

Edited May 28, 2015 by STGraves

[freshbrood]

Edit: I was wrong, please disregard what I asked before this edit. 

 

So from what I gather, PEEK is the "read" and POKE is the "write", is that correct?

 

Example: If I want to split the m variable in 2, calling one _M0 and the other _M1, would I read it as:

 

  if PEEK_M1 = 10 then goto __Label

 

And write it as

 

  POKE_M1 10

 

Without the use of the = sign? Is this correct? So far in testing it all seems to work. 

Edited April 2, 2023 by freshbrood
Variables are rolling over from 0 to 15

[+Gemintronic]

I started BASIC programming after systems that used PEEK and POKE heavily.  So, the terminology is awkward for me brains.

 

You might think about re-naming your defines to keep things straight in your head.

 

 def read_mapx=mapxy&$0F
 def write_mapx=callmacro _Set_Lo_Nibble mapxy

 def read_mapy=mapxy/4/4
 def write_mapy=callmacro _Set_Hi_Nibble mapxy

 

[freshbrood]

Gem I appreciate your responses but a more direct answer would help me better. I get confused easily myself. 

 

(Yes, that's pretty much how they work/no, not exactly etc..) I'm assuming it's yes then, I understand it correctly. 

 

(Also still trying to get an answer on if x is dedicated to use in MASE)

 

As a non coder-coder I actually appreciate using the proper terms as they may help me learn other "proper" languages. 

 

Thanks again. 

 

Edited April 3, 2023 by freshbrood