112 lines
2.1 KiB
ArmAsm
112 lines
2.1 KiB
ArmAsm
; text file parsing routines
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.export parse_integer
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.export parse_hex_digits
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.import mul_8_16
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.importzp acc16
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.include "zeropage.inc"
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.include "../inc/common.inc"
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target_string = ptr2
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.bss
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temp_value: .res 2
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.code
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; parses a string, returns integer (up to 16 bits)
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; inputs: AX points to a string containing an integer
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; outputs: AX contains integer
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parse_integer:
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stax target_string
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lda #0
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sta temp_value
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sta temp_value+1
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tay
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@parse_int:
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lda (target_string),y
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cmp #$30
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bcc @end_of_int ; any non-decimal char should be treated as end of integer
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cmp #$3A
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bcs @end_of_int ; any non-decimal char should be treated as end of integer
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ldax temp_value
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stax acc16
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lda #10
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jsr mul_8_16
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ldax acc16
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stax temp_value
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lda (target_string),y
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sec
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sbc #'0'
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clc
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adc temp_value
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sta temp_value
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bcc @no_rollover
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inc temp_value+1
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@no_rollover:
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iny
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bne @parse_int
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@end_of_int:
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ldax temp_value
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clc
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rts
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; parses 2 hex digits, returns a byte
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; inputs: X contains high nibble char, A contains low nibble char
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; outputs: A contains byte
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parse_hex_digits:
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pha
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txa
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jsr parse_1_digit
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asl
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asl
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asl
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asl
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sta temp_value
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pla
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jsr parse_1_digit
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clc
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adc temp_value
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rts
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parse_1_digit:
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cmp #$3A
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bcs @not_digit
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sec
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sbc #$30
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rts
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@not_digit:
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ora #$20 ; make lower case
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sec
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sbc #'a'-10
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rts
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; -- LICENSE FOR string_utils.s --
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; The contents of this file are subject to the Mozilla Public License
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; Version 1.1 (the "License"); you may not use this file except in
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; compliance with the License. You may obtain a copy of the License at
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; http://www.mozilla.org/MPL/
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;
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; Software distributed under the License is distributed on an "AS IS"
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; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
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; License for the specific language governing rights and limitations
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; under the License.
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;
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; The Original Code is ip65.
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;
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; The Initial Developer of the Original Code is Jonno Downes,
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; jonno@jamtronix.com.
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; Portions created by the Initial Developer are Copyright (C) 2009
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; Jonno Downes. All Rights Reserved.
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; -- LICENSE END --
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