// license:BSD-3-Clause // copyright-holders:Juergen Buchmueller /***************************************************************************** * * Xerox AltoII display word task * *****************************************************************************/ #include "alto2cpu.h" //! PROM a38 bit O1 is STOPWAKE' (stop DWT if bit is zero) #define FIFO_STOPWAKE(a38) (0 == (a38 & disp_a38_STOPWAKE) ? true : false) /** * @brief block the display word task */ void alto2_cpu_device::f1_early_dwt_block() { m_dsp.dwt_blocks = true; /* clear the wakeup for the display word task */ m_task_wakeup &= ~(1 << m_task); LOG((LOG_DWT,2," BLOCK %s\n", task_name(m_task))); /* wakeup the display horizontal task, if it didn't block itself */ if (!m_dsp.dht_blocks) m_task_wakeup |= 1 << task_dht; } /** * @brief load the display data register */ void alto2_cpu_device::f2_late_dwt_load_ddr() { LOG((LOG_DWT,2," DDR<- BUS (%#o)\n", m_bus)); m_dsp.fifo[m_dsp.wa] = m_bus; m_dsp.wa = (m_dsp.wa + 1) % ALTO2_DISPLAY_FIFO; UINT8 a38 = m_disp_a38[m_dsp.ra * 16 + m_dsp.wa]; if (FIFO_STOPWAKE(a38)) m_task_wakeup &= ~(1 << task_dwt); LOG((LOG_DWT,2, " DWT push %04x into FIFO[%02o]%s\n", m_bus, (m_dsp.wa - 1) & (ALTO2_DISPLAY_FIFO - 1), FIFO_STOPWAKE(a38) ? " STOPWAKE" : "")); } void alto2_cpu_device::init_dwt(int task) { set_f1(task, f1_block, &alto2_cpu_device::f1_early_dwt_block, 0); set_f2(task, f2_dwt_load_ddr, 0, &alto2_cpu_device::f2_late_dwt_load_ddr); } void alto2_cpu_device::exit_dwt() { // nothing to do yet } void alto2_cpu_device::reset_dwt() { m_dsp.dwt_blocks = false; memset(m_dsp.fifo, 0, sizeof(m_dsp.fifo)); m_dsp.wa = 0; m_dsp.ra = 0; }