cba54b205b
- refactor code for transfer buffer reads/writes, real mode int 0x21 calls, and assembler segment declarations - define transfer buffer size in one place - beef up error checking for transfer buffer operations (prevent buffer overflows) - also optimize such operations to transfer dword by dword where feasible
51 lines
852 B
ArmAsm
51 lines
852 B
ArmAsm
#
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! $Source$
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! $State$
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! $Revision$
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#include "libsysasm.h"
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! Read bytes from a file descriptor. These routines do not do any
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! translation between CRLF and LF line endings.
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!
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! Note that, for MS-DOS, a raw "write" request of zero bytes will truncate
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! (or extend) the file to the current file position.
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.define __sys_rawread
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__sys_rawread:
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file_handle = 1*4
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write_buffer = 2*4
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amount_to_read = 3*4
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mov eax, amount_to_read(esp)
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mov ecx, TRANSFER_BUFFER_SIZE
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cmp eax, ecx
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jge 2f
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mov ecx, eax
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2:
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! Read from DOS into the transfer buffer.
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movb ah, 0x3f
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o16 mov dx, (transfer_buffer_ptr)
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o16 mov bx, file_handle(esp)
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call .sys_dpmidos
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jc 3f
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! Copy eax bytes out of the transfer buffer.
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movzx ecx, ax
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mov eax, write_buffer(esp)
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call .sys_cpyin
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xchg eax, ecx
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ret
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3:
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! Process errors.
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push eax
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call __sys_seterrno
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pop ecx
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ret
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