Repeat problem 39, but when you transfer the string, remove any occurrences of the word “the”; for example, “and the man said” would become “and man said”.

What will be an ideal response?

There are several ways of dealing with this. One general technique would be to copy characters until you find a ‘t’ and then call a string matching algorithm to look for ‘the’. If you find ‘the’ continue copying after ‘the’. If not, continue copying at the initial ‘t’. This solution works with any string you are trying to remove.

If you don’t want a general solution, you could copy until a ‘t’ is found and then look ahead for ‘h’ and ‘e’. If you find them then continue from that point.

AREA RemoveThe, CODE, READWRITE

ADR r0,String1 ;r0 points to the source string

ADR r1,String2 ;r1 points to the dest string

Copy LDRB r2,[r0] ;read a byte (don't update the pointer)

CMP r2,#"t" ;is it a "t'?

BNE NotThe ;if not "t" then continue

LDRB r3,[r0,#1] ;get next char

CMP r3,#"h" ;is it an "h"?

BNE NotThe ;if not "h" then continue

LDRB r3,[r0,#2] ;get next char

CMP r3,#"e" ;is it an "e"?

BNE NotThe ;if not "e" then continue

ADD r0,r0,#3 ;"the" found, move source pointer on 3 bytes

B Copy ; continue with "the" removed

NotThe STRB r2,[r1,#1]! ;store char at destination and inc pointer

ADD r0,r0,#1 ;increment r0 pointer

CMP r2,#0x00 ;test for terminator(i.e., 0x00)

BNE Copy ;repeat until terminator found

SVC #0x123456 ;stop

AREA RemoveThe, code, READWRITE

String1 DCB "AB theABthe the ABthetheAB", 0x00 ;dummy string

String2 SPACE 40 ;reserve 40 bytes for copy

END