;Print characters 32..126 using a FOR loop-type construct
;R0 holds the character
MOV R0, #32 ;Init the character
.loop
SWI WriteC ;Print it
ADD R0, R0, #1 ;Increment it
CMP R0, #126 ;Check the limit
BLE loop ;Loop if not finished
;

Very often, we want to do something a fixed number of times, which could be expressed as a loop beginning FOR i=1 TO n... in BASIC. When such loops are encountered in assembler, we can use the fact that zero results of group one instructions can be made to set the Z flag. In such cases, the updating of the looping variable and the test for termination can be combined into one instruction.

For example, to print ten stars on the screen:

FOR i=1 TO 10
PRINT "*";
NEXT i

could be re-coded in the form:

;Print ten stars on the screen
;R0 holds the star character, R1 the count
MOV R0,#ASC"*" ;Init char to print
MOV R1,#10 ;Init count
.loop
SWI WriteC ;Print a star
SUBS R1,R1,#1 ;Next
BNE loop
;