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fs3216: DMA or may not? (nw)

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This commit is contained in:
AJR 2019-01-12 22:51:19 -05:00
parent bf10f9ce47
commit 1ffcd6ad48
1 changed files with 39 additions and 1 deletions
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40
src/mame/drivers/fs3216.cpp
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@ -72,6 +72,7 @@ private:
void floppy_select_w(offs_t offset, u16 data);
void floppy_control_w(u8 data);
u8 floppy_status_r();
TIMER_CALLBACK_MEMBER(fdc_dma);
u8 fdc_ram_r(offs_t offset);
void fdc_ram_w(offs_t offset, u8 data);
@ -99,6 +100,7 @@ private:
u8 m_floppy_select;
u8 m_fdc_select;
u16 m_fdc_dma_count;
emu_timer *m_fdc_dma_timer;
std::unique_ptr<u8[]> m_fdc_ram;
};
@ -110,12 +112,14 @@ void fs3216_state::machine_start()
std::fill(std::begin(m_mmu_reg), std::end(m_mmu_reg), 0);
m_floppy_status = 0;
m_floppy_status = 0x80;
m_floppy_control = 0;
m_floppy_select = 0;
m_fdc_select = 0;
m_fdc_dma_count = 0;
m_fdc_dma_timer = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(fs3216_state::fdc_dma), this));
save_item(NAME(m_mmu_reg));
save_item(NAME(m_from_reset));
save_item(NAME(m_floppy_status));
@ -263,9 +267,16 @@ WRITE_LINE_MEMBER(fs3216_state::fdc_int_w)
WRITE_LINE_MEMBER(fs3216_state::fdc_drq_w)
{
if (state)
{
m_floppy_status |= 0x01;
if (BIT(m_floppy_control, 3) && !m_fdc_dma_timer->enabled())
m_fdc_dma_timer->adjust(attotime::from_hz(16_MHz_XTAL / 64));
}
else
{
m_floppy_status &= 0xfe;
m_fdc_dma_timer->adjust(attotime::never);
}
}
WRITE_LINE_MEMBER(fs3216_state::fdc_hdl_w)
@ -338,6 +349,20 @@ void fs3216_state::floppy_control_w(u8 data)
m_fdc->tc_w(0);
}
if (BIT(data, 3) && BIT(m_floppy_status, 0))
{
if (!m_fdc_dma_timer->enabled())
{
m_fdc_dma_timer->adjust(attotime::from_hz(16_MHz_XTAL / 64));
m_floppy_status |= 0x04;
}
}
else
{
m_fdc_dma_timer->adjust(attotime::never);
m_floppy_status &= 0xfb;
}
m_fdc->set_unscaled_clock(16_MHz_XTAL / (BIT(data, 0) ? 4 : 2));
}
@ -346,6 +371,19 @@ u8 fs3216_state::floppy_status_r()
return m_floppy_status;
}
TIMER_CALLBACK_MEMBER(fs3216_state::fdc_dma)
{
if (BIT(m_floppy_control, 4))
m_fdc_ram[m_fdc_dma_count & 0x7ff] = m_fdc->dma_r();
else
m_fdc->dma_w(m_fdc_ram[m_fdc_dma_count & 0x7ff]);
m_floppy_status &= 0xfb;
++m_fdc_dma_count;
if (BIT(m_fdc_dma_count, 11))
m_fdc->tc_w(1);
}
u8 fs3216_state::fdc_ram_r(offs_t offset)
{
if (!machine().side_effects_disabled())