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- ## Copyright (C) 2017 Jeremiah Orians
- ## This file is part of stage0.
- ##
- ## stage0 is free software: you can redistribute it and/or modify
- ## it under the terms of the GNU General Public License as published by
- ## the Free Software Foundation, either version 3 of the License, or
- ## (at your option) any later version.
- ##
- ## stage0 is distributed in the hope that it will be useful,
- ## but WITHOUT ANY WARRANTY; without even the implied warranty of
- ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- ## GNU General Public License for more details.
- ##
- ## You should have received a copy of the GNU General Public License
- ## along with stage0. If not, see <http://www.gnu.org/licenses/>.
- DEFINE POP_eax 58
- DEFINE POP_ebx 5B
- DEFINE CMP_EAX_TO_IMMEDIATE8 83F8
- DEFINE JNE8 75
- DEFINE LOADI32_ECX B9
- DEFINE LOADI32_EAX B8
- DEFINE LOADI32_EBX BB
- DEFINE LOADI32_EDX BA
- DEFINE INT_80 CD80
- :_start
- # first check that we got the correct number of inputs
- POP_eax # Get the number of arguments
- POP_ebx # Get the program name
- POP_ebx # Get the actual argument
- # Check if we have the correct number of inputs
- CMP_EAX_TO_IMMEDIATE8 !02
- # Jump to Bail if the number is not correct
- JNE8 !Bail
- # Load our preferred mode (0777)
- LOADI32_ECX %0x1ff
- # Load the syscall number for chmod
- LOADI32_EAX %15
- # Call the kernel
- INT_80
- :Done
- # program completed Successfully
- LOADI32_EBX %0 # All is well
- LOADI32_EAX %1 # put the exit syscall number in eax
- INT_80 # Call it a good day
- :Bail
- # first let the user know what was wrong
- LOADI32_EDX %0x1a # third argument: message length
- LOADI32_ECX &msg # second argument: pointer to message to write
- LOADI32_EBX %1 # first argument: file handle (stdout)
- LOADI32_EAX %4 # system call number (sys_write)
- INT_80 # call kernel
- # Second terminate with an error
- LOADI32_EBX %1 # there was an error
- LOADI32_EAX %1 # put the exit syscall number in eax
- INT_80 # bail out
- :msg
- "needs a proper file name
- "
- :ELF_end
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