emailler/ip65/dottedquad.s
2013-12-13 22:24:03 +01:00

106 lines
2.2 KiB
ArmAsm

.include "../inc/common.i"
.export parse_dotted_quad
.export dotted_quad_value
.bss
dotted_quad_value: .res 4 ;set to 32 bit ip address on a succesful call to parse_dotted_quad
.data
;self modifying code
dotted_quad_ptr:
lda $FFFF
rts
.code
; convert a string representing a dotted quad (IP address, netmask) into 4 octets
; inputs:
; AX= pointer to null-terminated (*) string containing dotted quad
; e.g. "192.168.1.0",0
; outputs:
; carry flag is set if there was an error, clear otherwise
; dotted_quad_value: will be set to (32 bit) ip address (if no error)
; (*) NB to assist with url parsing, a ':' or '/' can also terminate the string
parse_dotted_quad:
stax dotted_quad_ptr+1
ldx #0
txa
sta dotted_quad_value
@each_byte:
jsr get_next_byte
cmp #0
beq @done
and #$7F ;turn off bit 7
cmp #'.'
beq @got_dot
cmp #':'
beq @done
cmp #'/'
beq @done
sec
sbc #'0'
bcc @error
cmp #10
bcs @error
clc
ldy #10
@mul_by_y:
adc dotted_quad_value,x
bcs @error
dey
bne @mul_by_y
sta dotted_quad_value,x
jmp @each_byte
@got_dot:
inx
cpx #4
beq @error
lda #0
sta dotted_quad_value,x
jmp @each_byte
@done:
cpx #3
bne @error
clc
rts
@error:
sec
rts
get_next_byte:
jsr dotted_quad_ptr
inc dotted_quad_ptr+1
bne :+
inc dotted_quad_ptr+2
:
rts
;-- LICENSE FOR dottedquad.s --
; The contents of this file are subject to the Mozilla Public License
; Version 1.1 (the "License"); you may not use this file except in
; compliance with the License. You may obtain a copy of the License at
; http://www.mozilla.org/MPL/
;
; Software distributed under the License is distributed on an "AS IS"
; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
; License for the specific language governing rights and limitations
; under the License.
;
; The Original Code is ip65.
;
; The Initial Developer of the Original Code is Jonno Downes,
; jonno@jamtronix.com.
; Portions created by the Initial Developer are Copyright (C) 2009
; Jonno Downes. All Rights Reserved.
; -- LICENSE END --