CP_PACKET0
*buffer++ = CP_PACKET0( RADEON_DP_GUI_MASTER_CNTL, 1 );
WRITE_RB( CP_PACKET0( RADEON_CP_IB_BASE, 2 ));
WRITE_RB( CP_PACKET0( RADEON_CP_IB_BASE, 2 ));
WRITE_RB( CP_PACKET0( RADEON_SCRATCH_REG1, 1 ));
do { buffer[0] = CP_PACKET0( (reg), 1 ); \