321 lines
7.4 KiB
Plaintext
321 lines
7.4 KiB
Plaintext
;; Copyright (C) 2017 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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DEFINE ADDI32_EAX 05
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DEFINE ADDI8_EDI 83C7
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DEFINE ADD_ESI_to_EAX 01F0
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DEFINE CALLI32 E8
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DEFINE CMPI8_EAX 83F8
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DEFINE CMPI8_EBP 83FD
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DEFINE COPY_EAX_to_ESI 89C6
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DEFINE INT_80 CD80
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DEFINE JE32 0F84
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DEFINE JL32 0F8C
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DEFINE JMP32 E9
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DEFINE JNE32 0F85
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DEFINE LOAD32_Absolute32_ebx 8B1D
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DEFINE LOAD32_Address_EAX_into_EAX 8B00
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DEFINE LOAD8_Absolute32_al A0
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DEFINE LOADI32_EAX B8
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DEFINE LOADI32_EBP BD
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DEFINE LOADI32_EBX BB
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DEFINE LOADI32_ECX B9
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DEFINE LOADI32_EDI BF
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DEFINE LOADI32_EDX BA
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DEFINE LOADI32_ESI BE
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DEFINE MOVZX 0FB6C0
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DEFINE NOT_EBP F7D5
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DEFINE NULL 00000000
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DEFINE POP_EAX 58
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DEFINE POP_EBX 5B
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DEFINE RET C3
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DEFINE SHLI8_EAX C1E0
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DEFINE SHLI8_ESI C1E6
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DEFINE STORE32_Absolute32_eax A3
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DEFINE STORE32_EDI_into_Address_EAX 8938
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DEFINE STORE8_Absolute32_al A2
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DEFINE SUBI8_EAX 83E8
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DEFINE SUB_EDI_from_EAX 29F8
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DEFINE TEST 85C0
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; Where the ELF Header is going to hit
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; Simply jump to _start
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; Our main function
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:_start
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POP_EAX ;·Get·the·number·of·arguments
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POP_EBX ;·Get·the·program·name
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POP_EBX ;·Get·the·actual·input name
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LOADI32_ECX %0 ;·prepare·read_only
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LOADI32_EDX %0 ;·extra sure
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LOADI32_EAX %5 ;·the·syscall·number·for·open()
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INT_80 ; Now open that damn file
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STORE32_Absolute32_eax &fin ; Preserve the file pointer we were given
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POP_EBX ;·Get·the·actual·output name
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LOADI32_ECX %577 ; Prepare file as O_WRONLY|O_CREAT|O_TRUNC
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LOADI32_EDX %448 ; Prepare file as RWX for owner only (700 in octal)
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LOADI32_EAX %5 ;·the·syscall·number·for·open()
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INT_80 ; Now open that damn file
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STORE32_Absolute32_eax &fout ; Preserve the file pointer we were given
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LOADI32_EBP %-1 ; Our flag for byte processing
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LOADI32_ESI %0 ; temp storage for the sum
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LOADI32_EDI %0 ; Our starting IP
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CALLI32 %First_pass ; Process it
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; rewind input file
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LOAD32_Absolute32_ebx &fin ; Using our input file
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LOADI32_ECX %0 ; Offset Zero
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LOADI32_EDX %0 ; Whence Zero
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LOADI32_EAX %19 ; lseek
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INT_80
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LOADI32_EBP %-1 ; Our flag for byte processing
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LOADI32_ESI %0 ; temp storage for the sum
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LOADI32_EDI %0 ; Our starting IP
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CALLI32 %Second_pass ; Process it
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JMP32 %Done
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:First_pass
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CALLI32 %Read_byte
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; Deal with EOF
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CMPI8_EAX !-4
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JE32 %First_pass_done
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; Check for :
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CMPI8_EAX !58
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JNE32 %First_pass_0
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; Deal with label
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CALLI32 %StoreLabel
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:First_pass_0
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; Check for :
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CMPI8_EAX !37
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JE32 %First_pass_pointer
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; Deal with everything else
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CALLI32 %hex ; Process our char
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; Deal with EOF
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CMPI8_EAX !-4
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JE32 %First_pass_done
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; deal with -1 values
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CMPI8_EAX !0
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JL32 %First_pass
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; deal with toggle
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CMPI8_EBP !0
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JE32 %First_pass_1
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ADDI8_EDI !1 ; Increment IP
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:First_pass_1
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NOT_EBP
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JMP32 %First_pass
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:First_pass_pointer
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; Deal with Pointer to label
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CALLI32 %Read_byte ; Drop the char
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ADDI8_EDI !4 ; Increment IP
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JMP32 %First_pass ; Loop again
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:First_pass_done
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RET
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:hex
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; deal with EOF
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CMPI8_EAX !-4
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JE32 %EOF
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; deal with line comments starting with ;
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CMPI8_EAX !35
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JE32 %ascii_comment
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; deal with line comments starting with ;
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CMPI8_EAX !59
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JE32 %ascii_comment
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; deal all ascii less than 0
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CMPI8_EAX !48
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JL32 %ascii_other
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; deal with 0-9
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CMPI8_EAX !58
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JL32 %ascii_num
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; deal with all ascii less than A
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CMPI8_EAX !65
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JL32 %ascii_other
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; deal with A-F
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CMPI8_EAX !71
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JL32 %ascii_high
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;deal with all ascii less than a
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CMPI8_EAX !97
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JL32 %ascii_other
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;deal with a-f
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CMPI8_EAX !103
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JL32 %ascii_low
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; The rest that remains needs to be ignored
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JMP32 %ascii_other
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:Second_pass
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CALLI32 %Read_byte
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; Deal with EOF
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CMPI8_EAX !-4
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JE32 %Second_pass_done
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; Simply drop the label
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CMPI8_EAX !58
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JNE32 %Second_pass_0
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CALLI32 %Read_byte
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JMP32 %Second_pass
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:Second_pass_0
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; Deal with pointer
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CMPI8_EAX !37
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JNE32 %Second_pass_1
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CALLI32 %StorePointer
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JMP32 %Second_pass
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:Second_pass_1
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; Deal with everything else
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CALLI32 %hex ; Process our char
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; Deal with EOF
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CMPI8_EAX !-4
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JE32 %Second_pass_done
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; deal with -1 values
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CMPI8_EAX !0
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JL32 %Second_pass
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; deal with toggle
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CMPI8_EBP !0
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JE32 %print
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; process first byte of pair
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COPY_EAX_to_ESI
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LOADI32_EBP %0
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JMP32 %Second_pass
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:Second_pass_done
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RET
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:EOF
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RET
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:ascii_num
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SUBI8_EAX !48
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RET
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:ascii_low
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SUBI8_EAX !87
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RET
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:ascii_high
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SUBI8_EAX !55
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RET
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:ascii_other
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LOADI32_EAX %-1
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RET
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:ascii_comment
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CALLI32 %Read_byte
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CMPI8_EAX !13
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JE32 %ascii_comment_cr
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CMPI8_EAX !10
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JNE32 %ascii_comment
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:ascii_comment_cr
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LOADI32_EAX %-1
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RET
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; process second byte of pair
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:print
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; update the sum and store in output
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SHLI8_ESI !4
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ADD_ESI_to_EAX
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STORE8_Absolute32_al &table
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; flip the toggle
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NOT_EBP
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; Print our first Hex
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LOADI32_EDX %1 ; set the size of chars we want
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CALLI32 %print_chars
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ADDI8_EDI !1 ; Increment IP
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JMP32 %Second_pass
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:Done
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; program completed Successfully
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LOADI32_EBX %0 ; All is well
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LOADI32_EAX %1 ; put the exit syscall number in eax
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INT_80 ; Call it a good day
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:Read_byte
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; Attempt to read 1 byte from STDIN
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LOADI32_EDX %1 ; set the size of chars we want
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LOADI32_ECX &table ; Where to put it
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LOAD32_Absolute32_ebx &fin ; Where are we reading from
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LOADI32_EAX %3 ; the syscall number for read
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INT_80 ; call the Kernel
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TEST ; check what we got
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JE32 %Read_byte_1 ; Got EOF call it done
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; load byte
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LOAD8_Absolute32_al &table ; load char
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MOVZX ; We have to zero extend it to use it
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RET
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; Deal with EOF
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:Read_byte_1
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LOADI32_EAX %-4 ; Put EOF in eax
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RET
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:print_chars
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LOADI32_ECX &table ; What we are writing
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LOAD32_Absolute32_ebx &fout ; Write to target file
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LOADI32_EAX %4 ; the syscall number for write
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INT_80 ; call the Kernel
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RET
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:Get_table_target
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CALLI32 %Read_byte ; Get single char label
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SHLI8_EAX !2 ; Each label in table takes 4 bytes to store
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ADDI32_EAX &table ; Calculate offset
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RET
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:StoreLabel
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CALLI32 %Get_table_target
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STORE32_EDI_into_Address_EAX ; Write out pointer to table
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RET
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:StorePointer
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ADDI8_EDI !4 ; Increment IP
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CALLI32 %Get_table_target ; Get address of pointer
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LOAD32_Address_EAX_into_EAX ; Get pointer
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SUB_EDI_from_EAX ; target - ip
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STORE32_Absolute32_eax &table ; put value in output
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LOADI32_EDX %4 ; set the size of chars we want
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CALLI32 %print_chars
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RET
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:fin
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NULL
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:fout
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NULL
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:table
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:ELF_end
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