218 lines
7.0 KiB
Plaintext
218 lines
7.0 KiB
Plaintext
## Copyright (C) 2016 Jeremiah Orians
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## This file is part of stage0.
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##
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## stage0 is free software: you can redistribute it and/or modify
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## it under the terms of the GNU General Public License as published by
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## the Free Software Foundation, either version 3 of the License, or
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## (at your option) any later version.
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##
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## stage0 is distributed in the hope that it will be useful,
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## but WITHOUT ANY WARRANTY; without even the implied warranty of
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## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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## GNU General Public License for more details.
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##
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## You should have received a copy of the GNU General Public License
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## along with stage0. If not, see <http://www.gnu.org/licenses/>.
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# :start 0
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E0002D2B0200 # LOADUI R11 0x200 ; Where we are putting our address pointers
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0D00003C # TRUE R12 ; Our toggle
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0D00002D # FALSE R13 ; Our PC counter
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E0002D2E0050 # LOADUI R14 $getLables_2 ; our first iterator
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# ;; We will be using R15 for holding our processed nybbles
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# ;; Prep TAPE_01
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E0002D201100 # LOADUI R0 0x1100
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42100000 # FOPEN_READ
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# ;; Prep TAPE_02
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E0002D201101 # LOADUI R0 0x1101
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42100001 # FOPEN_WRITE
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E0002D211100 # LOADUI R1 0x1100 ; Read from tape_01
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# ;; Function for collecting the address of all labels
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# :getLables 2e
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42100100 # FGETC ; Read a Char
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# ;; Check for EOF
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E0002CC00052 # JUMP.NP R0 @stage2
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# ;; Check for Label
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E000A030003a # CMPSKIPI.NE R0 58 ; If the Char is : the next char is the label
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3C000036 # JUMP @storeLabel
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# ;; Check for pointer to label
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E000A0300040 # CMPSKIPI.NE R0 64 ; If the Char is @ the next char is the pointer to a label
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3C00001e # JUMP @ignorePointer
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# ;; Otherwise attempt to process
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3C000100 # JUMP @hex ; Convert it
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# :getLables_2 50
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E0002CC0ffd8 # JUMP.NP R0 @getLables ; Don't record, nonhex values
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090006CC # NOT R12 R12 ; Flip the toggle
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E0002C9Cffce # JUMP.Z R12 @getLables ; First half doesn't need anything
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# ;; Deal with case of second half of byte
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E1000FDD0001 # ADDUI R13 R13 1 ; increment PC now that we have a full byte
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3C00ffc4 # JUMP @getLables
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# :ignorePointer 6a
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# ;; Ignore the pointer for now
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42100100 # FGETC ; Read a Char
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E1000FDD0002 # ADDUI R13 R13 2 ; The pointer will end up taking 2 bytes
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3C00ffb6 # JUMP @getLables
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# ;; Function for storing the address of the label
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# :storeLabel 78
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# ;; Get the char of the Label
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42100100 # FGETC ; Read a Char
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# ;; We require 2 bytes to store the pointer values
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E0002D500001 # SL0I R0 1 ; Thus we multiply our label by 2
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# ;; Store the current Program counter
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0504ADB0 # STOREX16 R13 R11 R0
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# ;; Label is safely stored, return
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3C00ffa4 # JUMP @getLables
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# ;; Now that we have all of the label addresses,
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# ;; We can process input to produce our output
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# :stage2 8a
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# ;; We first need to rewind tape_01 to perform our second pass
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E0002D201100 # LOADUI R0 0x1100
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42100003 # REWIND
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# ;; Reset our toggle and counter
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E0002D291101 # LOADUI R9 0x1101 ; Where to write the combined byte
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0D00003C # TRUE R12 ; Our toggle
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0D00002D # FALSE R13 ; Our PC counter
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E0002D2E00ca # LOADUI R14 $loop_hex ; The hex return target
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# :loop a8
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42100100 # FGETC ; Read a Char
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# ;; Check for EOF
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E0002CC0010e # JUMP.NP R0 @finish
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# ;; Check for Label
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E000A030003a # CMPSKIPI.NE R0 58 ; Make sure we jump over the label
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3C00004e # JUMP @ignoreLabel
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# ;; Check for Pointer
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E000A0300040 # CMPSKIPI.NE R0 64 ; If it is a pointer Deal with it
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3C00004c # JUMP @storePointer
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# ;; Process Char
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3C000086 # JUMP @hex ; Convert it
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# :loop_hex ca
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E0002CC0ffd8 # JUMP.NP R0 @loop ; Don't use nonhex chars
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090006CC # NOT R12 R12 ; Flip the toggle
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E0002CAC000a # JUMP.NZ R12 @loop_second_nybble ; Jump if toggled
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# ;; Process first byte of pair
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E100B0F0000f # ANDI R15 R0 0xF ; Store First nibble
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3C00ffc4 # JUMP @loop
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# :loop_second_nybble e4
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E0002D5F0004 # SL0I R15 4 ; Shift our first nibble
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E100B000000f # ANDI R0 R0 0xF ; Mask out top
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0500000F # ADD R0 R0 R15 ; Combine nibbles
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09000319 # SWAP R1 R9 ; Set to write to tape_2
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42100200 # FPUTC ; To TAPE_02
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09000319 # SWAP R1 R9 ; Restore from tape_1
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E1000FDD0001 # ADDUI R13 R13 1 ; increment PC now that we have a full byte
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3C00ff9e # JUMP @loop ; Try to get more bytes
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# :ignoreLabel 10a
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# ;; Consume next char
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42100100 # FGETC ; Read a Char
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3C00ff96 # JUMP @loop
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# :storePointer 112
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# ;; Correct the PC to reflect the size of the pointer
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E1000FDD0002 # ADDUI R13 R13 2 ; Exactly 2 bytes
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# ;; Get the char of the Label
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42100100 # FGETC ; Read a Char
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# ;; Since we stored a short pointer taking up 2 bytes
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E0002D500001 # SL0I R0 1 ; Thus we multiply our label by 2 to get where it is stored
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0503C3B0 # LOADXU16 R3 R11 R0 ; Load the address of the label
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# ;; We now have to calculate the distance and store the 2 bytes
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0500233D # SUB R3 R3 R13 ; First determine the difference between the current PC and the stored PC of the label
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# ;; Store Upper byte
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E100B003ff00 # ANDI R0 R3 0xFF00 ; Mask out everything but top byte
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E0002D400008 # SARI R0 8 ; Drop the bottom 8 bits
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09000319 # SWAP R1 R9 ; Write the byte
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42100200 # FPUTC ; To TAPE_02
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# ;; Store Lower byte
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E100B00300ff # ANDI R0 R3 0xFF ; Preserve bottom half for later
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42100200 # FPUTC ; Write the byte to TAPE_02
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09000319 # SWAP R1 R9 ; Restore Read
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3C00ff58 # JUMP @loop
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# ;; Hex function
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# ;; Returns hex value of ascii char
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# ;; Or -1 if not a hex char
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# :hex 150
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# ;; Deal with line comments starting with #
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E000A0300023 # CMPSKIPI.NE R0 35
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3C000050 # JUMP @ascii_comment
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# ;; Deal with line comments starting with ;
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E000A030003b # CMPSKIPI.NE R0 59
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3C000046 # JUMP @ascii_comment
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# ;; Deal with all ascii less than '0'
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E000A0100030 # CMPSKIPI.GE R0 48
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3C00004a # JUMP @ascii_other
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# ;; Deal with '0'-'9'
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E000A0000039 # CMPSKIPI.G R0 57
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3C00001e # JUMP @ascii_num
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# ;; Deal with all ascii less than 'A'
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E000A0100041 # CMPSKIPI.GE R0 65
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3C000036 # JUMP @ascii_other
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# ;; Unset high bit to set everything into uppercase
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E100B00000df # ANDI R0 R0 0xDF
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# ;; Deal with 'A'-'F'
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E000A0000046 # CMPSKIPI.G R0 70
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3C00000e # JUMP @ascii_high
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# ;; Ignore the rest
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3C000022 # JUMP @ascii_other
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# :ascii_num 196
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E10011000030 # SUBUI R0 R0 48
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0D01000E # JSR_COROUTINE R14
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# :ascii_high 1a0
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E10011000037 # SUBUI R0 R0 55
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0D01000E # JSR_COROUTINE R14
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# :ascii_comment 1aa
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42100100 # FGETC ; Read another char
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E000A020000a # CMPSKIPI.E R0 10 ; Stop at the end of line
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3C00fff2 # JUMP @ascii_comment ; Otherwise keep looping
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# :ascii_other 1b8
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0D000030 # TRUE R0
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0D01000E # JSR_COROUTINE R14
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# :finish 1c0
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E0002D201100 # LOADUI R0 0x1100 ; Close TAPE_01
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42100002 # FCLOSE
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E0002D201101 # LOADUI R0 0x1101 ; Close TAPE_02
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42100002 # FCLOSE
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FFFFFFFF # HALT
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# ;; Where all of our pointers will be stored for our locations
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# :table 1d8
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