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Gury

Mad-Assembler (MADS)

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Unary operators:

+ Plus (does nothing)

- Minus (changes sign)

~ Bitwise not (complements all bits)

! Logical not (changes true to false and vice versa)

< Low (extracts low byte)

> High (extracts high byte)

^ High 24bit (extracts high byte)

= Extracts memory bank

: Extracts global variable value

Bitwise not will turn %00000001 to %11111110, not %10000000 (bit reverse) like ascrnet asked :(. I'm not sure if there is a reverse bits function in mads but worst case you can probably create a macro that does this for you. Or maybe tebe can add that functionality.

Edited by ggn

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Oh, sure, I didn't read correctly. Here's one way:

lines	= 8

	org $2000

	.proc mirror_player
	ldx #.len player-1
loop_x	lda player,x
	ldy #8
loop_y	asl
	ror player_mirrored,x
	dey
	bne loop_y
	dex
	bpl loop_x
	rts
	.endp

	.local player
	.byte %00000001
	.byte %00000011
	.byte %00000111
	.byte %00001111
	.byte %00011111
	.byte %00111111
	.byte %01111111
        .byte %11111111
	.endl
	
	.local player_mirrored
	.rept lines
	.byte $00
	.endr
	.endl

Another way would be to use WUDSN's graphics converter, to convert the bitmap directly to the desired format including mirroring without generating any source. But that belongs to another thread.

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:-o thank you very much JAC! for the example!!!!!

 

I was failing to do it, since it had not occurred to me to use a variable with zeros when trying to invert the bits of a byte.

 

so I leave it in my code and it works:

.macro pm_escorpion :sprite
	ldx #12
read_escorpion
	.if :1=1
	lda escorpion_1,x
	.else
	lda escorpion_2,x
	.endif
	ldy #8
mirrored
	asl
	ror player_temp,x
	dey
	bne mirrored
	dex
	bpl read_escorpion
	ldx #00
read_temp	
	lda player_temp,x
	sta VPOSP2+116,x
	inx
	cpx #12
	bne read_temp
.endm

Just a doubt of your second option uses less RAM or more :?

regards

 

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:-o thank you very much JAC! for the example!!!!!

 

I was failing to do it, since it had not occurred to me to use a variable with zeros when trying to invert the bits of a byte.

 

Just a doubt of your second option uses less RAM or more :?

 

regards

IDE would simply create the normal plus the reversed data like you originally did by hand. Whether this requires more or less RAM (in the XEX) than generating the reverse data at runtime depend on many factors (number of sprites, the height of sprites, ...). And after all, it doesn't matter for a normal project.

 

In your case, you could pass the parameters to the subroutine, instead of duplicating the code with the macro.

	mwa #scorpion1 mirror_player.source
	jsr mirror_player
	...

	.proc mirror_player
	ldx #.len player-1
loop_x	lda player,x
source	= *-2
	ldy #8

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IDE would simply create the normal plus the reversed data like you originally did by hand. Whether this requires more or less RAM (in the XEX) than generating the reverse data at runtime depend on many factors (number of sprites, the height of sprites, ...). And after all, it doesn't matter for a normal project.

 

In your case, you could pass the parameters to the subroutine, instead of duplicating the code with the macro.

	mwa #scorpion1 mirror_player.source
	jsr mirror_player
	...

	.proc mirror_player
	ldx #.len player-1
loop_x	lda player,x
source	= *-2
	ldy #8

 

understood thank you very much for the explanation, I will follow your recommendation to not repeat the code. :-D

 

regards

  • Like 1

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Regarding the + in Xasm or quickasm... I never understood that you type + and it does nothing?

 

Always run into that when getting source from Eric or Fox.

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Hi guys,

is it possible to run .rept within .rept in order to do something like this?

for x,0,nosprites-1
 for y,0,3
  dta (sprites+14*y*4+x*14*4*4) / 256
 next
next
Edited by matosimi

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?varX = 0

.rept nosprites

:4 .byte >(sprites+14*#*4+?varX*14*4*4)

?varX++

.endr

 

Don't remember about nested repts, but something like this should work..

 

Working example from some code:

 

?cy = 0

.rept ITEM_MATRIX_SIZEY

:ITEM_MATRIX_SIZEX .byte <[screenBuffer1+LINE_SIZE+1+[?cy*3*LINE_SIZE+3*#]]

?cy++

.endr

 

I believe nested repts were added in the last few years, but you should test it.

Edited by NRV

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Hi guys,

 

is it possible to run .rept within .rept in order to do something like this?

 

for x,0,nosprites-1
 for y,0,3
  dta (sprites+14*y*4+x*14*4*4) / 256
 next
next
nosprites = 5

.macro m_do_x_y x y
  .echo ,:y
.endm

.macro m_for_y x
  .rept 4
  	m_do_x_y ,#
  .endr

.endm

.rept nosprites
  m_for_y #
.endr

  • Like 3

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@JAC!: Your solution is utterly evil :D

 

It's just the way I used to do it back in ATASM and because typically in inner code is more complex, so I prefer this type of "subroutining".

In MADS the most straightforward translation does not need macro, but only aliasing of # via variables.

	.rept 8
	  ?x=#
	  .rept 4
	    ?y=#
	    dta [sprites+14*?y*4+?x*14*4*4] / 256
	   .endr
	.endr 
  • Like 2

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	.rept 8
	  ?x=#
	  .rept 4
	    ?y=#
	    dta [sprites+14*?y*4+?x*14*4*4] / 256
	   .endr
	.endr 

Love this one, because I don't need to rewrite insides of those repeats, only minimal touch is needed.

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I have been playing around with BBC Micro code and I have found one handy feature of beebasm compiler (directive) which is called "guard".

So "guard" is coupled with previous "org" and it looks like this:

org $2000
guard $2100
;bla bla code
org $2100
;bla bla data

if your code is so long that compiler reaches $2100 it shows the error that code reached guarded address.

This way it could be possible to prevent code and data overlapping... which sometimes occurs if you are not carefull enough.

 

note: to be honest, this could help me back in the days when I was using orgs very much, but these days i'm usually placing all data after code separated by .align and additional orgs I usually use only when adding rastapictures,g2f or rmt.

Edited by matosimi
  • Like 1

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Sounds like you could simulate "guard $2100" with ert, e.g.:

 

  org $2000
  :257 dta 0
  ert *>$2100 ; Previous block exceeds boundary

Xasm outputs:

 

    ert *>$2100 ; Previous block exceeds boundary
t.asm (3) ERROR: User-defined error

Mads outputs:

 

    ert *>$2100 ; Previous block exceeds boundary
t.asm (3) ERROR: User error

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Sounds like you could simulate "guard $2100" with ert, e.g.:

 

  org $2000
  :257 dta 0
  ert *>$2100 ; Previous block exceeds boundary
Xasm outputs:

 

    ert *>$2100 ; Previous block exceeds boundary
t.asm (3) ERROR: User-defined error
Mads outputs:

 

    ert *>$2100 ; Previous block exceeds boundary
t.asm (3) ERROR: User error

 

And then a simple extension to Xuel's helpful suggestion is to make a 'guard' macro, so it will feel like the Beeb.

 

.macro guard
ert *>:1
.endm
Invoked with : guard $C000
  • Like 4
  • Thanks 1

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Just wondering how do people handle strings of text to be put on screen with MADS?

.sb 'Text'

converts to ATASCII codes, which is great, but

.cb 'Text'

does EOR $80 to the last character which is perfect to denote the end, except it is only ASCII and not ATASCII?

IE the capitals don't work.

Is there a simple trick I'm missing to have it do the EOR for ATASCII codes, or am I just approaching things the wrong way?

Thanks!

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Use "Text" or d'Text' to encode strings as INTERNAL instead of ATASCII.

 

Thanks, that does work for "dta" but not ".cb" unfortunately :(

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Not ideal, but you could manually add $80 to the last byte:

 

    org $2000
    .sb 'This is a high-bit terminated strin' 'g'+$80
  • Like 1

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Yep, thanks. looks like I'll have to be doing that.

 

On another note, is .align supposed to work to exact bytes rather than just pages? Not that it turns out to be that useful for padding out to 128 byte sectors, but when I was experimenting it seems to behave peculiarity with things like ".align $7f"?

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I use:

 

.byte 'string',0

 

But Sheddy wants to set the high bit of the last character of the string to serve as a terminator. I guess a macro would do it if macros can iterate through string arguments.

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