17 lines
626 B
ArmAsm
17 lines
626 B
ArmAsm
global ft_read
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extern __errno_location
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ft_read:
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mov eax, 0 ; move the syscall code of write (0) into eax (syscall register)
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syscall
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test rax, rax ; check if the syscall failed
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js .error ; if the syscall failed, jump at .error
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ret ; else return
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.error:
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mov rdx, rax ; save rax (return value) into rdx as a temp value
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call __errno_location wrt ..plt ; call errno_location (put errno pointer into rax) | wrt ..plt means the address of the function will be defined at runtime (needed for libc)
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neg rdx ; invert the return value
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mov [rax], rdx ; *errno_value = rdx
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mov rax, -1 ; set the return value to -1
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ret ; return
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