; Description: ; If An ETX Is Found, Return With DPTR Pointing To It, And CY == 0. If ; No ETX Found, Return DPTR Pointing At One Byte Past End, And CY == 1. ; ; Entry Requirements: ; DPTR Points To External Memory ; R0 Contains Maximum Length To Search ; ; On Exit: ; CY == 0 Indicates ETX Found, DPTR Points To ETX ; CY == 1 Indicated ETX Not Found, DPTR = DPTR + R0 ; ; Affected: ; PSW.CY, PSW.Z, PSW.P, Acc, DPTR, R0 ; ; Stack: ; 1 Bytes, Not Including Space Used By Called Routines ; ; Comments: ; None ;
ETX equ 3 ; ASCII ETX Character UTIL_FIND_ETX: push 0 ; Save R0 ; loop1: movx a,@dptr ; Get Character cjne a,#ETX,temp ; If ETX, Skip temp: jmp loop2 ; inc dptr ; Next Location djnz r0,loop1 ; Repeat Up To R0 ; pop 0 ; Recover R0 setb c ; ETX Not Found ret ; Return To Caller ; loop2: pop 0 ; Recover R0 clr c ; ETX Found ret ; Return To Caller
Source: Assorted Utilities, John C. Wren 11/23/96
Related topics:
8051 Program - replace 0x00 with ETX in string | 8051 Program - remove trailing spaces | 8051 Program - return length of string | 8051 Program - memory subroutines | 8051 Program - math subroutines | 8051 Program - conversion subroutines
List of topics: 8051
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