77 lines
1.8 KiB
ArmAsm
77 lines
1.8 KiB
ArmAsm
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.data
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# we must export the entry point to the ELF linker or loader.
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# They convientionally recognize _start as their entry point.
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# Use ld -e main to override the default if you wish
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.global _start
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_start:
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# first check that we got the correct number of inputs
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pop %rax # Get the number of arguments
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pop %rdi # Get the program name
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pop %rdi # Get the actual argument
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# Check if we have the correct number of inputs
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cmp $2, %rax
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# Jump to Bail if the number is not correct
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jne Bail
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# attempt to open the file for reading
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mov $0, %rsi # prepare read_only
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# we already have what we need in ebx
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mov $2, %rax # the syscall number for open()
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syscall # call the Kernel
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# Check if we have a valid file
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test %rax, %rax
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# Jump to Bail_file if not actual file
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js Bail
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mov %rax, %rdi # move the pointer to the right location
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Circle: #print contents of file
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mov $read_size, %rdx # set the size of chars we want
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mov $buffer, %rsi # Where to put it
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# We already have what we need in ebx
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mov $0, %rax # the syscall number for read
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syscall # call the Kernel
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test %rax, %rax # check what we got
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jz Done # Got EOF call it done
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# Make sure we don't write a bunch of NULLs
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mov %rax, %rdx
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# get file pointer out of the way
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movq %rdi, %rsp
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# edx was already setup
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mov $1, %rdi # setup stdout write
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mov $1, %rax # setup the write
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syscall # call the Kernel
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#now to prepare for next loop
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movq %rsp, %rdi
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jmp Circle
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Done:
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# program completed Successfully
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mov $0, %rdi # All is well
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mov $60, %rax # put the exit syscall number in eax
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syscall # Call it a good day
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Bail:
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# terminate with an error
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mov $1, %rdi # there was an error
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mov $60, %rax # put the exit syscall number in eax
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syscall # bail out
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# Our writable space
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# 2^ 30 Should be enough per read
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read_size = 1073741824
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buffer:
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.space 1
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