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huc6270.cpp: moved VRAM-VRAM DMA from vblank callback to hsync, fixes MT #06701 (nw)

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This commit is contained in:
angelosa 2017-10-11 15:09:26 +02:00
parent acff2222fb
commit 2b01da2494
2 changed files with 38 additions and 34 deletions
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71
src/devices/video/huc6270.cpp
View File

@ -501,40 +501,6 @@ WRITE_LINE_MEMBER( huc6270_device::vsync_changed )
/* Check for low->high VSYNC transition */
// VBlank IRQ happens at the beginning of HDW period after VDW ends
handle_vblank();
/* Should we perform VRAM-VRAM dma.
The timing for this is incorrect.
*/
if ( m_dma_enabled )
{
int desr_inc = ( m_dcr & 0x0008 ) ? -1 : +1;
int sour_inc = ( m_dcr & 0x0004 ) ? -1 : +1;
LOG("doing dma sour = %04x, desr = %04x, lenr = %04x\n", m_sour, m_desr, m_lenr );
do {
uint16_t data;
// area 0x8000-0xffff cannot be r/w (open bus)
if((m_sour & 0x8000) == 0)
data = m_vram[ m_sour & m_vram_mask ];
else
data = 0;
if((m_desr & 0x8000) == 0)
m_vram[ m_desr & m_vram_mask ] = data;
m_sour += sour_inc;
m_desr += desr_inc;
m_lenr -= 1;
} while ( m_lenr != 0xFFFF );
if ( m_dcr & 0x0002 )
{
m_status |= HUC6270_DV;
m_irq_changed_cb( ASSERT_LINE );
}
m_dma_enabled = 0;
}
}
}
@ -577,6 +543,7 @@ WRITE_LINE_MEMBER( huc6270_device::hsync_changed )
while ( m_horz_to_go == 0 )
next_horz_state();
handle_dma();
}
else
{
@ -593,6 +560,42 @@ WRITE_LINE_MEMBER( huc6270_device::hsync_changed )
m_hsync = state;
}
inline void huc6270_device::handle_dma()
{
/* Should we perform VRAM-VRAM dma.
The timing for this is incorrect.
*/
if ( m_dma_enabled )
{
int desr_inc = ( m_dcr & 0x0008 ) ? -1 : +1;
int sour_inc = ( m_dcr & 0x0004 ) ? -1 : +1;
LOG("doing dma sour = %04x, desr = %04x, lenr = %04x\n", m_sour, m_desr, m_lenr );
do {
uint16_t data;
// area 0x8000-0xffff cannot be r/w (open bus)
if((m_sour & 0x8000) == 0)
data = m_vram[ m_sour & m_vram_mask ];
else
data = 0;
if((m_desr & 0x8000) == 0)
m_vram[ m_desr & m_vram_mask ] = data;
m_sour += sour_inc;
m_desr += desr_inc;
m_lenr -= 1;
} while ( m_lenr != 0xFFFF );
if ( m_dcr & 0x0002 )
{
m_status |= HUC6270_DV;
m_irq_changed_cb( ASSERT_LINE );
}
m_dma_enabled = 0;
}
}
READ8_MEMBER( huc6270_device::read )
{

1
src/devices/video/huc6270.h
View File

@ -52,6 +52,7 @@ protected:
inline void handle_vblank();
inline void next_vert_state();
inline void next_horz_state();
inline void handle_dma();
private:
enum class v_state : u8 {