110 lines
3.5 KiB
Plaintext
110 lines
3.5 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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E0002D2B0001 # LOADUI R11 1 ; Our toggle
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# ;; R15 is storing our nybble
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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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# ;; Main program loop
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# ;; Halts when done
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# :loop 20
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42100100 # FGETC ; Read a Char
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# ;; Check for EOF
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E0002CC000b8 # JUMP.NP R0 @finish
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3C000044 # JUMP @hex ; Convert it
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# :loop_1 2e
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E0002CC0ffec # JUMP.NP R0 @loop ; Don't use nonhex chars
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E0002C9B000e # JUMP.Z R11 @loop_2 ; 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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0D00002B # FALSE R11 ; Flip the toggle
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3C00ffd8 # JUMP @loop
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# :loop_2 48
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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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E0002D1B0001 # LOADI R11 1 ; Flip the toggle
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E0002D211101 # LOADUI R1 0x1101 ; Write the combined byte
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42100200 # FPUTC ; To TAPE_02
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E0002D211100 # LOADUI R1 0x1100 ; Read from tape_01
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3C00ffae # JUMP @loop ; Try to get more bytes
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# ;; Hex function
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# ;; Converts Ascii chars to their hex values
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# ;; Or -1 if not a hex char
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# ;; Returns to whatever called it
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# :hex 72
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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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# ;; Unset high bit to set everything into uppercase
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E100B00000df # ANDI R0 R0 0xDF
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# ;; Deal with all ascii less than 'A'
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E000A0100041 # CMPSKIPI.GE R0 65
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3C000030 # JUMP @ascii_other
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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 b8
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E10011000030 # SUBUI R0 R0 48
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3C00ff6c # JUMP @loop_1
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# :ascii_high c2
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E10011000037 # SUBUI R0 R0 55
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3C00ff62 # JUMP @loop_1
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# :ascii_comment cc
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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 da
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0D000030 # TRUE R0
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3C00ff4c # JUMP @loop_1
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# ;; Finish function
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# ;; Cleans up at the end of the program
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# ;; Performs the HALT
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# :finish e2
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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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