I have an odd problem with a program on a 4K ROM 16C73.  Any suggestions
are appreciated.  Right up front I'll confess my sin of being a C
programmer (CCS's compiler on the PIC's) and not an assembler guy.

Having said that, I have a function "Display" that gets called twelve
times in my program.  The function displays the string which starts in
external EEPROM memory location to an LCD starting at a particular row
and column.

The first ten times, the function is called from within the first 2K and
works fine and complies as shown in the first code example.  The last
two times that it is called, the function is called from the second half
of the 4K code space.  These two function calls compile differently from
the first ten.  The problem is that the second code example doesn't work
well.

TWO QUESTIONS:

1. Is this is due to some difference in how the PIC handles the first 2K
and the second 2K ???

2. What is the purpose of the BCF and BSF commands surrounding the
function call in the second code example and why could this cause a
problem ???



CODE EXAMPLE 1
.................... Display(ST_NO_SHOTS_HEARD,2,1);    <- the C to be
compiled
051C:  MOVLW  0B        <- the constant ST_NO_SHOTS_HEARD is decimal 11
051D:  MOVWF  6D
051E:  MOVLW  02        <- save the first parameter, I assume
051F:  MOVWF  6E
0520:  MOVLW  01        <- save the second parameter, I assume
0521:  MOVWF  6F
0522:  CALL   38E       <- and call the function


CODE EXAMPLE #2
.................... Display(ST_NO_SHOTS_HEARD,2,1);    <- the C to be
compiled
0942:  MOVLW  0B
0943:  MOVWF  6D
0944:  MOVLW  02
0945:  MOVWF  6E
0946:  MOVLW  01
0947:  MOVWF  6F
0948:  BCF    0A,3      <- the call has BCF/BSF surrounding it. why?
0949:  CALL   38E
094A:  BSF    0A,3