FilterChars

Synopsis

FilterChars(address, len, lo_range, hi_range, Rchar)
            A0       D0   D1        D2        D3

C Prototype

void FilterChars(STRPTR address, ULONG len, ULONG lo_range, ULONG hi_range, ULONG Rchar);

Description

Performs the basic function of ChangeChar(), but instead of replacing a single character, it operates on a range of codes. All characters outside the range defined by lo_range and hi_range are replaced with the character Rchar.

Inputs

• address — Pointer to the memory area to filter.
• len — Number of bytes to filter.
• lo_range — Minimum value below which codes will be replaced.
• hi_range — Maximum value above which codes will be replaced.
• Rchar — ASCII code that will be placed in position of those outside the range.

Result

None.

See Also

• ChangeChar

Implementation

The original 68020 assembly implementation:

; (25-Feb-1995) --- FilterChars()
_LVOFilterChars
        movem.l d4/a0,-(sp)
        subq.w  #1,d0
        moveq   #0,d4
 
FC_Start
        move.b  (a0),d4
        cmp.b   d1,d4
        bmi.s   FC_Replace
        cmp.b   d2,d4
        bhi.s   FC_Replace
        bra.s   FC_Repeat
 
FC_Replace
        move.b  d3,(a0)
 
FC_Repeat
        addq.w  #1,a0
        dbf     d0,FC_Start
        movem.l (sp)+,d4/a0
        rts