8051 Program - remove trailing spaces

; Description:

; Removes Trailing Spaces From A String In External Memory That Is

; <= R0 In Length By Placing An ETX Character At The First Non-Space

; Character From The End.

;

; Entry Requirements:

; DPTR Points To String In External Memory

; R0 Contains Index Into String To Start Search From

;

; On Exit:

; DPTR Points To Location ETX Stored To

; Acc = ETX

;

; Affected:

; PSW.Z, PSW.P, Acc, DPTR

;

; Stack:

; 5 Bytes, Not Including Space Used By Called Routines

;

; Comments:

; If No Spaces Are Found, An ETX Is Stored To The First Position In

; The String.

;

	ETX equ 3	; ASCII ETX Character
	SPACE equ 32	; ASCII Space Character
UTIL_TRIM:
	push 0	; Save R0
	push dph	; Save DPH
	push dpl	; Save DPL
		;
	mov a,r0	; Get Length To Acc
	dec a	; Make 0 Based, Not 1
	call UTIL_ADCAD	; Point To Last Byte
loop1:	movx a,@dptr	; Get Character From Buffer
	cjne a,#SPACE,loop2	; If Not Space, Exit
	call UTIL_DPTRDEC	; Next Location Back
	djnz r0,loop1	; Repeat R0 Times
		;
	pop dpl	; Recover Buffer Start Low
	pop dph	; Recover Buffer Start High
	mov a,#ETX	; ETX Character
	movx @dptr,a	; Store Terminator
	pop 0	; Recover R0
	ret	; Return To Caller
;
; Now Get The Modem Index Number From The Modem Buffer, And Append It
;
loop2:	inc dptr	; 1st Char Past Non-Space
	mov a,#ETX	; ETX Character
	movx @dptr,a	; Store Terminator
		;
	pop dpl	; Recover DPL
	pop dph	; Recover DPH
	pop 0	; Recover R0
	ret	; Return To Caller

Source: Assorted Utilities, John C. Wren 11/23/96

---

<< Previous :: Up :: Next >>

---

Related topics:
8051 Program - replace 0x00 with ETX in string   |   8051 Program - locate ETX in string   |   8051 Program - return length of string   |   8051 Program - memory subroutines   |   8051 Program - math subroutines   |   8051 Program - conversion subroutines

---

List of topics: 8051

---