ack/plat/msdos386/libsys/sys_rawwrite.s

68 lines
1.2 KiB
ArmAsm

#
! $Source$
! $State$
! $Revision$
! Declare segments (the order is important).
.sect .text
.sect .rom
.sect .data
.sect .bss
.sect .text
.extern pmode_ds
.extern pmode_cs
.extern rmode
.extern transfer_buffer_ptr
.extern interrupt_ptr
! Write bytes to/to a file descriptor. These routines do not do any
! translation between CRLF and LF line endings.
!
! Note that, for MS-DOS, a raw "write" request of zero bytes will truncate
! (or extend) the file to the current file position.
.define __sys_rawwrite
__sys_rawwrite:
enter 0, 0
file_handle = 2*4
read_buffer = 3*4
amount_to_write = 4*4
mov eax, amount_to_write(ebp)
mov ecx, 32*1024 ! size of transfer buffer
cmp eax, ecx
jge 2f
mov ecx, eax
2:
! Copy ecx bytes into the transfer buffer.
push ecx
mov esi, read_buffer(ebp)
movzx edi, (transfer_buffer_ptr)
mov es, (pmode_ds)
cld
rep movsb
pop ecx
! Write from the transfer buffer to DOS.
movb ah, 0x40
o16 mov dx, (transfer_buffer_ptr)
o16 mov bx, file_handle(ebp)
or ebx, 0x210000
callf (interrupt_ptr)
jnc exit
push eax
call __sys_seterrno
exit:
leave
ret
! vim: sw=4 ts=4 et