diff options
author | 2012-09-08 21:27:33 +0000 | |
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committer | 2012-09-08 21:27:33 +0000 | |
commit | f4f21579fe27ca4d08e738f8b0799166a1a06f44 (patch) | |
tree | 972547c016d903ec28f9d9c4f9c168b1af6eedf3 /src/mess/machine/genpc.c | |
parent | 417f123e8ebc432a9284b5256aa66cde3b175877 (diff) |
(mess) pc hardware: cleanup the end-of-dma notifications [O. Galibert]
Diffstat (limited to 'src/mess/machine/genpc.c')
-rw-r--r-- | src/mess/machine/genpc.c | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/src/mess/machine/genpc.c b/src/mess/machine/genpc.c index ec9f708f30a..4ac87bd56d0 100644 --- a/src/mess/machine/genpc.c +++ b/src/mess/machine/genpc.c @@ -69,6 +69,8 @@ WRITE_LINE_MEMBER( ibm5160_mb_device::pc_dma_hrq_changed ) READ8_MEMBER( ibm5160_mb_device::pc_dma_read_byte ) { + if(m_dma_channel == -1) + return 0xff; address_space *spaceio = m_maincpu->space(AS_PROGRAM); offs_t page_offset = (((offs_t) m_dma_offset[m_dma_channel]) << 16) & 0x0F0000; return spaceio->read_byte( page_offset + offset); @@ -77,6 +79,8 @@ READ8_MEMBER( ibm5160_mb_device::pc_dma_read_byte ) WRITE8_MEMBER( ibm5160_mb_device::pc_dma_write_byte ) { + if(m_dma_channel == -1) + return; address_space *spaceio = m_maincpu->space(AS_PROGRAM); offs_t page_offset = (((offs_t) m_dma_offset[m_dma_channel]) << 16) & 0x0F0000; @@ -127,13 +131,29 @@ WRITE8_MEMBER( ibm5160_mb_device::pc_dma8237_0_dack_w ) WRITE_LINE_MEMBER( ibm5160_mb_device::pc_dma8237_out_eop ) { - return m_isabus->eop_w(state == ASSERT_LINE ? 0 : 1 ); + m_cur_eop = state == ASSERT_LINE; + if(m_dma_channel != -1 && m_cur_eop) + m_isabus->eop_w(m_dma_channel, m_cur_eop ? ASSERT_LINE : CLEAR_LINE ); } -WRITE_LINE_MEMBER( ibm5160_mb_device::pc_dack0_w ) { if (!state) m_dma_channel = 0; } -WRITE_LINE_MEMBER( ibm5160_mb_device::pc_dack1_w ) { if (!state) m_dma_channel = 1; } -WRITE_LINE_MEMBER( ibm5160_mb_device::pc_dack2_w ) { if (!state) m_dma_channel = 2; } -WRITE_LINE_MEMBER( ibm5160_mb_device::pc_dack3_w ) { if (!state) m_dma_channel = 3; } +void ibm5160_mb_device::pc_select_dma_channel(int channel, bool state) +{ + if(!state) { + m_dma_channel = channel; + if(m_cur_eop) + m_isabus->eop_w(channel, ASSERT_LINE ); + + } else if(m_dma_channel == channel) { + m_dma_channel = -1; + if(m_cur_eop) + m_isabus->eop_w(channel, CLEAR_LINE ); + } +} + +WRITE_LINE_MEMBER( ibm5160_mb_device::pc_dack0_w ) { pc_select_dma_channel(0, state); } +WRITE_LINE_MEMBER( ibm5160_mb_device::pc_dack1_w ) { pc_select_dma_channel(1, state); } +WRITE_LINE_MEMBER( ibm5160_mb_device::pc_dack2_w ) { pc_select_dma_channel(2, state); } +WRITE_LINE_MEMBER( ibm5160_mb_device::pc_dack3_w ) { pc_select_dma_channel(3, state); } I8237_INTERFACE( pc_dma8237_config ) { @@ -651,7 +671,8 @@ void ibm5160_mb_device::device_reset() m_out1 = 2; // initial state of pit output is undefined m_pc_spkrdata = 0; m_pc_input = 0; - m_dma_channel = 0; + m_dma_channel = -1; + m_cur_eop = false; memset(m_dma_offset,0,sizeof(m_dma_offset)); m_ppi_portc_switch_high = 0; m_ppi_speaker = 0; |