ddmmaaoonn() -- Accessible Kernel Routine

#iinncclluuddee <ssyyss/ttyyppeess.hh>
iinntt
ddmmaaoonn(_c_h_a_n, _p_a_d_d_r, _c_o_u_n_t, _w_f_l_a_g)
iinntt _c_h_a_n;
ppaaddddrr_tt _p_a_d_d_r;
uunnssiiggnneedd _c_o_u_n_t;
iinntt _w_f_l_a_g;

ddmmaaoonn()  programs DMA  channel  _c_h_a_n to  transfer  _c_o_u_n_t bytes  to or  from
physical-memory address  _p_a_d_d_r.  If _w_f_l_a_g  is zero, the data  are read from
the device and written to memory.

If the  operation is successfully  programmed, ddmmaaoonn() returns  one.  A DMA
straddle arises when an operation would cross a 64-kilobyte physical memory
boundary.  As  the DMA controller  cannot handle a  straddle condition, the
operation is not programmed and ddmmaaoonn() returns zero.

_S_e_e _A_l_s_o
aacccceessssiibbllee kkeerrnneell rroouuttiinneess
