8051 Program - count ascii decimal in string

; Description:

; DPTR Points To An ETX Terminated String In External Memory. Count

; The Number Of ASCII Digits In The String. If The Number Of Digits

; Exceeds 255, Return CY == 1, Else Return Digit Count In Acc And

; CY == 0. DPTR Is Modified.

;

; Entry Requirements:

; DPTR Points To ETX Terminated String In External Memory

;

; On Exit:

; CY == 0, Acc Has Number Of Digits ('0'..'9') Found

; CY == 1, Number Of Digits Found Exceeds 255

; DPTR Points To ETX

;

; Affected:

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

;

; Stack:

; 1 Bytes, Not Including Space Used By Called Routines

;

; Comments:

; None

;

	ETX equ 3	; ASCII ETX Character
UTIL_CNTDG:
	push 0	; Save R0
	mov r0,#0	; Clear Counter
loop1:	movx a,@dptr	; Get Character
	cjne a,#ETX,temp	; Exit If End Of String
temp:	jmp loop2	;
	inc dptr	; Next Character
	cjne a,#'0',temp1	; Skip If < '0'
temp1:	jc loop1	;
	cjne a,#'9',temp2	; Skip If > '9'
	jmp temp3	;
temp2:	jnc loop1	;
temp3:		;
	inc r0	; Increment Counter
	mov a,r0	; Get Counter
	jnz loop1	; Repeat Count
	setb c	; Too Many Digits
	pop 0	; Recover R0
	ret	; Return To Caller
		;
loop2:	mov a,r0	; Get Count To Acc
	clr c	; Clear For No Error
	pop 0	; Recover R0
	ret	; Return To Caller

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

---

<< Previous :: Up :: Next >>

---

Related topics:
8051 Program - unsigned divide   |   8051 Program - unsigned mod   |   8051 Program - signed divide   |   8051 Program - signed mod   |   8051 Program - sign fixup for divide   |   8051 Program - divide   |   8051 Program - memory subroutines   |   8051 Program - math subroutines   |   8051 Program - conversion subroutines

---

List of topics: 8051

---