Moving Bytes

JDOhio

I have a few places in code where I move bytes around like this:

FOR Index=0 to 6
    There(Index)=Here(Index)
NEXT

Since I have a few places, I would rather have a subroutine to call such as

MoveBytes Here,There, 6

I'm not familiar with a couple things.

1) How might I pass the address of a memory location to a subroutine?
2) Once I am in the subroutine, how might I read one location and place it in another?
3) Did I make this too hard?

This was my attempt:

temp1=4
ASM
MOV __PARAM1,#Here & $FF
MOV __PARAM2,#Here >> 8
MOV __PARAM3,#There & $FF
MOV __PARAM4,#There >> 8
MOV FSR,#__PARAMCNT
MOV IND,#4
MOV FSR,#$10 
CALL @__MoveBytes
ENDASM

MoveBytes:
temp2=__PARAM1
temp3=__PARAM2
tempA=__PARAM3
tempB=__PARAM4
FOR ACount=0 to temp1
    READ temp2+temp3,temp4
    ASM
        MOV FSR,#tempA+tempB
        MOV IND,temp4
        INC tempB
    ENDASM
NEXT

RETURN

I'd much rather prefer something like

MOV W,#Here                ;                      There(Index)=Here(Index)
ADD W,Index                     
MOV FSR,W                     
MOV __PARAM2,IND              
MOV FSR,#$10                  
MOV W,#There          
ADD W,Index                     
MOV FSR,W                     
MOV IND,__PARAM2

But I'm not sure how to set up the address indirection.

Joe

Bean

This will do it...

DEVICE SX28, OSC4MHZ, TURBO, STACKX, OPTIONX
FREQ 4_000_000
 
here  VAR Byte (7)
there VAR Byte (7)
 
 
CopyBytes SUB 3
 
 
PROGRAM Start NOSTARTUP
 
 
Start:
  PUT here, "ABCDEFG"
  CopyBytes here, there, 7
END

 
 
CopyBytes:
  ASM
:Again:
    MOV W,__PARAM1
    MOV FSR,W
    MOV W,IND
    MOV __PARAM4,W
    MOV W,__PARAM2
    MOV FSR,W
    MOV W,__PARAM4
    MOV IND,W
    INC __PARAM1
    INC __PARAM2
    DJNZ __PARAM3, :Again
  ENDASM
  RETURN

In SX/B array names are just constants into the virtual __RAM array.

So you can do "tempbyte = __RAM(here)"

or you can assign the variable name to a byte variable and use that as an index into __RAM

tempByte = here
__RAM(tempByte) = "A" ' Same as here(0) = "A"
INC tempByte
__RAM(tempByte) = "B" ' Same as here(1) = "B"

Bean.

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Post Edited (Bean (Hitt Consulting)) : 8/11/2006 2:09:13 AM GMT

John Couture

Ooo! Ooo! Bean, make sure that makes it into the SX/B manual .... maybe a section on "advanced coding techniques". Very kool!

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John J. Couture

San Diego Miramar College