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(MESS) nes_mmc5: further cleanups (this time for NT-RAM handling). no visible improvements,

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but it bothered me that we were saving as NVRAM the external RAM, while it was volatile in real 
carts. nw.
This commit is contained in:
Fabio Priuli 2014-02-07 13:30:33 +00:00
parent dd91beb013
commit 1aa7194558
3 changed files with 54 additions and 29 deletions
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74
src/mess/machine/nes_mmc5.c
View File

@ -79,9 +79,6 @@ void nes_exrom_device::device_start()
m_exram = auto_alloc_array_clear(machine(), UINT8, 0x400);
save_pointer(NAME(m_exram), 0x400);
m_mapper_sram_size = 0x400;
m_mapper_sram = m_exram;
}
void nes_exrom_device::pcb_reset()
@ -121,22 +118,6 @@ void nes_exrom_device::pcb_reset()
}
READ8_MEMBER(nes_exrom_device::nt_r)
{
int page = ((offset & 0xc00) >> 10);
if (m_nt_src[page] == MMC5FILL)
{
if ((offset & 0x3ff) >= 0x3c0)
return m_floodattr;
return m_floodtile;
}
return m_nt_access[page][offset & 0x3ff];
}
/*-------------------------------------------------
mapper specific handlers
-------------------------------------------------*/
@ -348,16 +329,16 @@ void nes_exrom_device::set_mirror(int page, int src)
{
switch (src)
{
case 0: /* CIRAM0 */
case 0:
set_nt_page(page, CIRAM, 0, 1);
break;
case 1: /* CIRAM1 */
case 1:
set_nt_page(page, CIRAM, 1, 1);
break;
case 2: /* ExRAM */
set_nt_page(page, EXRAM, 0, 1); // actually only works during rendering.
case 2:
set_nt_page(page, EXRAM, 0, 1);
break;
case 3: /* Fill Registers */
case 3:
set_nt_page(page, MMC5FILL, 0, 0);
break;
default:
@ -366,6 +347,51 @@ void nes_exrom_device::set_mirror(int page, int src)
}
}
READ8_MEMBER(nes_exrom_device::nt_r)
{
int page = ((offset & 0xc00) >> 10);
switch (m_nt_src[page])
{
case MMC5FILL:
if ((offset & 0x3ff) >= 0x3c0)
return m_floodattr;
return m_floodtile;
case EXRAM:
if (!BIT(m_exram_control, 1))
return m_exram[offset & 0x3ff];
else
return 0x00;
case CIRAM:
default:
return m_nt_access[page][offset & 0x3ff];
}
}
WRITE8_MEMBER(nes_exrom_device::nt_w)
{
int page = ((offset & 0xc00) >> 10);
if (!m_nt_writable[page])
return;
switch (m_nt_src[page])
{
case EXRAM:
m_exram[offset & 0x3ff] = data;
break;
case CIRAM:
default:
m_nt_access[page][offset & 0x3ff] = data;
break;
}
}
READ8_MEMBER(nes_exrom_device::read_l)
{
int value;

1
src/mess/machine/nes_mmc5.h
View File

@ -19,6 +19,7 @@ public:
virtual DECLARE_WRITE8_MEMBER(write_l);
virtual DECLARE_WRITE8_MEMBER(write_m);
virtual DECLARE_READ8_MEMBER(nt_r);
virtual DECLARE_WRITE8_MEMBER(nt_w);
virtual void hblank_irq(int scanline, int vblank, int blanked);
virtual void pcb_reset();

8
src/mess/machine/nes_slot.c
View File

@ -503,15 +503,13 @@ void device_nes_cart_interface::set_nt_page(int page, int source, int bank, int
case CART_NTRAM:
base_ptr = m_ext_ntram;
break;
case MMC5FILL:
base_ptr = NULL;
break;
case VROM:
bank &= ((m_vrom_chunks << 3) - 1);
base_ptr = m_vrom;
break;
case EXRAM:
base_ptr = m_mapper_sram;
case MMC5FILL:
base_ptr = NULL;
break;
case CIRAM:
default:
@ -522,7 +520,7 @@ void device_nes_cart_interface::set_nt_page(int page, int source, int bank, int
page &= 3; /* mask down to the 4 logical pages */
m_nt_src[page] = source;
if (base_ptr != NULL)
if (base_ptr)
{
m_nt_orig[page] = bank * 0x400;
m_nt_access[page] = base_ptr + m_nt_orig[page];