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author 0kmg <9137159+0kmg@users.noreply.github.com>2022-02-04 18:15:16 -0900
committer GitHub <noreply@github.com>2022-02-04 22:15:16 -0500
commit09c4c23136172b40f37cfed3b08f182dccac12d4 (patch)
tree1b7e171a9679697b854556852058ff11d80d9a48 /src/devices/bus/nes
parentfff6c5e9fd910f4f20bd7ba0c8f40a8700ccc16c (diff)
nes_slot.cpp: Unified CHR banking into a common function. (#9261)
* nes_slot.cpp: Unified CHR banking into a common function. - Removed PPU_MIRROR_NONE as an option for nametable mirroring. - Shrunk over-allocated 4-screen NT RAM to correct 4K size. - Sundry minor clean ups. - Only calculate start of bank once.
Diffstat (limited to 'src/devices/bus/nes')
-rw-r--r--src/devices/bus/nes/mmc3_clones.cpp9
-rw-r--r--src/devices/bus/nes/nes_slot.cpp189
-rw-r--r--src/devices/bus/nes/nes_slot.h41
3 files changed, 78 insertions, 161 deletions
diff --git a/src/devices/bus/nes/mmc3_clones.cpp b/src/devices/bus/nes/mmc3_clones.cpp
index 6b8807175e7..b9a989c78e0 100644
--- a/src/devices/bus/nes/mmc3_clones.cpp
+++ b/src/devices/bus/nes/mmc3_clones.cpp
@@ -2678,12 +2678,11 @@ void nes_bmc_jy208_device::write_m(offs_t offset, u8 data)
nes_bmc_hik8_device::write_m(offset, data);
if (BIT(m_reg[2], 6))
- {
- set_nt_mirroring(PPU_MIRROR_4SCREEN); // actually change NT pointers
- m_mirroring = PPU_MIRROR_4SCREEN; // prevent MMC3 mirror switching
- }
+ m_mirroring = PPU_MIRROR_4SCREEN; // prevent MMC3 mirror switching
else
- m_mirroring = PPU_MIRROR_NONE; // allow MMC3 mirror switching
+ m_mirroring = BIT(m_mmc_mirror, 0) ? PPU_MIRROR_HORZ : PPU_MIRROR_VERT; // allow MMC3 mirror switching and get its current setting
+
+ set_nt_mirroring(m_mirroring); // actually change nametable pointers
}
/*-------------------------------------------------
diff --git a/src/devices/bus/nes/nes_slot.cpp b/src/devices/bus/nes/nes_slot.cpp
index 54709f4b03e..aee85bbb2a5 100644
--- a/src/devices/bus/nes/nes_slot.cpp
+++ b/src/devices/bus/nes/nes_slot.cpp
@@ -130,7 +130,7 @@ device_nes_cart_interface::device_nes_cart_interface(const machine_config &mconf
, m_outer_prg_size(0)
, m_outer_chr_size(0)
, m_smd133_addr(0x6000)
- , m_mirroring(PPU_MIRROR_NONE)
+ , m_mirroring(PPU_MIRROR_HORZ)
, m_pcb_ctrl_mirror(false)
, m_four_screen_vram(false)
, m_has_trainer(false)
@@ -174,26 +174,24 @@ void device_nes_cart_interface::prg_alloc(size_t size, const char *tag)
m_prg_chunks--;
}
- m_prg_mask = ((m_prg_chunks << 1) - 1);
+ m_prg_mask = (m_prg_chunks << 1) - 1;
// printf("first mask %x!\n", m_prg_mask);
if ((m_prg_chunks << 1) & m_prg_mask)
{
- int mask_bits = 0, temp = (m_prg_chunks << 1), mapsize;
+ int mask_bits = 0;
// contrary to what happens with later systems, like e.g. SNES or MD,
// only half a dozen of NES carts have PRG which is not a power of 2
// so we use this bank_map only as an exception
// printf("uneven rom!\n");
// 1. redefine mask as (next power of 2)-1
- for (; temp; )
- {
+ for (int temp = m_prg_chunks << 1; temp; temp >>= 1)
mask_bits++;
- temp >>= 1;
- }
+
m_prg_mask = (1 << mask_bits) - 1;
// printf("new mask %x!\n", m_prg_mask);
- mapsize = (1 << mask_bits)/2;
+ int mapsize = (1 << mask_bits) / 2;
// 2. create a bank_map for banks in the range mask/2 -> mask
m_prg_bank_map.resize(mapsize);
@@ -206,7 +204,7 @@ void device_nes_cart_interface::prg_alloc(size_t size, const char *tag)
while (j % mapsize)
{
int k = 0, repeat_banks;
- while ((j % (mapsize >> k)) && k < mask_bits)
+ while (j % (mapsize >> k) && k < mask_bits)
k++;
repeat_banks = j % (mapsize >> (k - 1));
for (int l = 0; l < repeat_banks; l++)
@@ -271,20 +269,20 @@ void device_nes_cart_interface::battery_alloc(size_t size)
inline int device_nes_cart_interface::prg_8k_bank_num(int bank_8k)
{
- if (m_prg_mask == ((m_prg_chunks << 1) - 1))
+ if (m_prg_mask == (m_prg_chunks << 1) - 1)
return bank_8k & m_prg_mask;
// only a few pirate games (less than a dozen) have PRG which is not power of 2
// so we treat it here separately, rather than forcing all games to use m_prg_bank_map
// case 1: if we are accessing a bank before the end of the image, just return that bank
- if (bank_8k < ((m_prg_chunks << 1) - 1))
+ if (bank_8k < (m_prg_chunks << 1) - 1)
return bank_8k;
// case 2: otherwise return a mirror using the bank_map!
// uint8_t temp = bank_8k;
bank_8k &= m_prg_mask;
- bank_8k -= (m_prg_mask/2 + 1);
+ bank_8k -= m_prg_mask / 2 + 1;
// printf("bank: accessed %x (top: %x), returned %x\n", temp, (m_prg_chunks << 1) - 1, m_prg_bank_map[bank_8k]);
return m_prg_bank_map[bank_8k];
}
@@ -303,11 +301,11 @@ inline void device_nes_cart_interface::update_prg_banks(int prg_bank_start, int
void device_nes_cart_interface::prg32(int bank)
{
- /* if there is only 16k PRG, return */
+ // if there is only 16k PRG, return
if (!(m_prg_chunks >> 1))
return;
- /* assumes that bank references a 32k chunk */
+ // assumes that bank references a 32k chunk
bank = prg_8k_bank_num(bank * 4);
m_prg_bank[0] = bank + 0;
@@ -319,7 +317,7 @@ void device_nes_cart_interface::prg32(int bank)
void device_nes_cart_interface::prg16_89ab(int bank)
{
- /* assumes that bank references a 16k chunk */
+ // assumes that bank references a 16k chunk
bank = prg_8k_bank_num(bank * 2);
m_prg_bank[0] = bank + 0;
@@ -329,7 +327,7 @@ void device_nes_cart_interface::prg16_89ab(int bank)
void device_nes_cart_interface::prg16_cdef(int bank)
{
- /* assumes that bank references a 16k chunk */
+ // assumes that bank references a 16k chunk
bank = prg_8k_bank_num(bank * 2);
m_prg_bank[2] = bank + 0;
@@ -353,110 +351,36 @@ void device_nes_cart_interface::prg8_x(int start, int bank)
// CHR helpers
//-------------------------------------------------
-inline void device_nes_cart_interface::chr_sanity_check( int source )
+void device_nes_cart_interface::bank_chr(int shift, int start, int bank, int source)
{
- if (source == CHRRAM && m_vram.empty())
- fatalerror("CHRRAM bankswitch with no VRAM\n");
-
- if (source == CHRROM && m_vrom == nullptr)
- fatalerror("CHRROM bankswitch with no VROM\n");
-}
-
-void device_nes_cart_interface::chr8(int bank, int source)
-{
- chr_sanity_check(source);
+ uint8_t *base_ptr;
+ uint32_t chr_chunks;
if (source == CHRRAM)
{
- bank &= (m_vram_chunks - 1);
- for (int i = 0; i < 8; i++)
- {
- m_chr_src[i] = source;
- m_chr_orig[i] = (bank * 0x2000) + (i * 0x400); // for save state uses!
- m_chr_access[i] = &m_vram[m_chr_orig[i]];
- }
- }
- else
- {
- bank &= (m_vrom_chunks - 1);
- for (int i = 0; i < 8; i++)
- {
- m_chr_src[i] = source;
- m_chr_orig[i] = (bank * 0x2000) + (i * 0x400); // for save state uses!
- m_chr_access[i] = &m_vrom[m_chr_orig[i]];
- }
- }
-}
+ assert(!m_vram.empty());
-void device_nes_cart_interface::chr4_x(int start, int bank, int source)
-{
- chr_sanity_check(source);
-
- if (source == CHRRAM)
- {
- bank &= ((m_vram_chunks << 1) - 1);
- for (int i = 0; i < 4; i++)
- {
- m_chr_src[i + start] = source;
- m_chr_orig[i + start] = (bank * 0x1000) + (i * 0x400); // for save state uses!
- m_chr_access[i + start] = &m_vram[m_chr_orig[i + start]];
- }
+ base_ptr = &m_vram[0];
+ chr_chunks = m_vram_chunks;
}
- else
+ else // source == CHRROM
{
- bank &= ((m_vrom_chunks << 1) - 1);
- for (int i = 0; i < 4; i++)
- {
- m_chr_src[i + start] = source;
- m_chr_orig[i + start] = (bank * 0x1000) + (i * 0x400); // for save state uses!
- m_chr_access[i + start] = &m_vrom[m_chr_orig[i + start]];
- }
- }
-}
+ assert(m_vrom != nullptr);
-void device_nes_cart_interface::chr2_x(int start, int bank, int source)
-{
- chr_sanity_check(source);
-
- if (source == CHRRAM)
- {
- bank &= ((m_vram_chunks << 2) - 1);
- for (int i = 0; i < 2; i++)
- {
- m_chr_src[i + start] = source;
- m_chr_orig[i + start] = (bank * 0x800) + (i * 0x400); // for save state uses!
- m_chr_access[i + start] = &m_vram[m_chr_orig[i + start]];
- }
+ base_ptr = m_vrom;
+ chr_chunks = m_vrom_chunks;
}
- else
- {
- bank &= ((m_vrom_chunks << 2) - 1);
- for (int i = 0; i < 2; i++)
- {
- m_chr_src[i + start] = source;
- m_chr_orig[i + start] = (bank * 0x800) + (i * 0x400); // for save state uses!
- m_chr_access[i + start] = &m_vrom[m_chr_orig[i + start]];
- }
- }
-}
-void device_nes_cart_interface::chr1_x(int start, int bank, int source)
-{
- chr_sanity_check(source);
+ bank &= (chr_chunks << (3 - shift)) - 1;
+ int size = 0x400 << shift;
+ int bank_start = bank * size;
+ int kbyte = 1 << shift;
- if (source == CHRRAM)
- {
- bank &= ((m_vram_chunks << 3) - 1);
- m_chr_src[start] = source;
- m_chr_orig[start] = (bank * 0x400); // for save state uses!
- m_chr_access[start] = &m_vram[m_chr_orig[start]];
- }
- else
+ for (int i = 0; i < kbyte; i++)
{
- bank &= ((m_vrom_chunks << 3) - 1);
- m_chr_src[start] = source;
- m_chr_orig[start] = (bank * 0x400); // for save state uses!
- m_chr_access[start] = &m_vrom[m_chr_orig[start]];
+ m_chr_src[i + start] = source;
+ m_chr_orig[i + start] = bank_start + i * 0x400; // for save state uses!
+ m_chr_access[i + start] = &base_ptr[m_chr_orig[i + start]];
}
}
@@ -466,7 +390,7 @@ void device_nes_cart_interface::chr1_x(int start, int bank, int source)
void device_nes_cart_interface::set_nt_page(int page, int source, int bank, int writable)
{
- uint8_t* base_ptr;
+ uint8_t *base_ptr;
switch (source)
{
@@ -474,7 +398,7 @@ void device_nes_cart_interface::set_nt_page(int page, int source, int bank, int
base_ptr = &m_ext_ntram[0];
break;
case VROM:
- bank &= ((m_vrom_chunks << 3) - 1);
+ bank &= (m_vrom_chunks << 3) - 1;
base_ptr = m_vrom;
break;
case EXRAM:
@@ -487,7 +411,7 @@ void device_nes_cart_interface::set_nt_page(int page, int source, int bank, int
break;
}
- page &= 3; /* mask down to the 4 logical pages */
+ page &= 3; // mask down to the 4 logical pages
m_nt_src[page] = source;
if (base_ptr)
@@ -501,20 +425,21 @@ void device_nes_cart_interface::set_nt_page(int page, int source, int bank, int
void device_nes_cart_interface::set_nt_mirroring(int mirroring)
{
- /* setup our videomem handlers based on mirroring */
+ // setup our videomem handlers based on mirroring
switch (mirroring)
{
- case PPU_MIRROR_VERT:
+ default:
+ case PPU_MIRROR_HORZ:
set_nt_page(0, CIRAM, 0, 1);
- set_nt_page(1, CIRAM, 1, 1);
- set_nt_page(2, CIRAM, 0, 1);
+ set_nt_page(1, CIRAM, 0, 1);
+ set_nt_page(2, CIRAM, 1, 1);
set_nt_page(3, CIRAM, 1, 1);
break;
- case PPU_MIRROR_HORZ:
+ case PPU_MIRROR_VERT:
set_nt_page(0, CIRAM, 0, 1);
- set_nt_page(1, CIRAM, 0, 1);
- set_nt_page(2, CIRAM, 1, 1);
+ set_nt_page(1, CIRAM, 1, 1);
+ set_nt_page(2, CIRAM, 0, 1);
set_nt_page(3, CIRAM, 1, 1);
break;
@@ -539,14 +464,6 @@ void device_nes_cart_interface::set_nt_mirroring(int mirroring)
set_nt_page(2, CART_NTRAM, 2, 1);
set_nt_page(3, CART_NTRAM, 3, 1);
break;
-
- case PPU_MIRROR_NONE:
- default:
- set_nt_page(0, CIRAM, 0, 1);
- set_nt_page(1, CIRAM, 0, 1);
- set_nt_page(2, CIRAM, 1, 1);
- set_nt_page(3, CIRAM, 1, 1);
- break;
}
}
@@ -623,7 +540,7 @@ uint8_t device_nes_cart_interface::chr_r(offs_t offset)
void device_nes_cart_interface::nt_w(offs_t offset, uint8_t data)
{
- int page = ((offset & 0xc00) >> 10);
+ int page = (offset & 0xc00) >> 10;
if (!m_nt_writable[page])
return;
@@ -633,7 +550,7 @@ void device_nes_cart_interface::nt_w(offs_t offset, uint8_t data)
uint8_t device_nes_cart_interface::nt_r(offs_t offset)
{
- int page = ((offset & 0xc00) >> 10);
+ int page = (offset & 0xc00) >> 10;
return m_nt_access[page][offset & 0x3ff];
}
@@ -708,7 +625,7 @@ void device_nes_cart_interface::pcb_start(running_machine &machine, uint8_t *cir
if (m_four_screen_vram)
{
- m_ext_ntram.resize(0x2000);
+ m_ext_ntram.resize(0x1000);
device().save_item(NAME(m_ext_ntram));
}
@@ -803,7 +720,7 @@ void nes_cart_slot_device::pcb_reset()
-------------------------------------------------*/
-/* Include emulation of NES PCBs for softlist */
+// Include emulation of NES PCBs for softlist
#include "nes_pcb.hxx"
@@ -813,7 +730,7 @@ void nes_cart_slot_device::pcb_reset()
-------------------------------------------------*/
-/* Include emulation of UNIF Boards for .unf files */
+// Include emulation of UNIF Boards for .unf files
#include "nes_unif.hxx"
@@ -823,7 +740,7 @@ void nes_cart_slot_device::pcb_reset()
-------------------------------------------------*/
-/* Include emulation of iNES Mappers for .nes files */
+// Include emulation of iNES Mappers for .nes files
#include "nes_ines.hxx"
@@ -835,11 +752,11 @@ image_init_result nes_cart_slot_device::call_load()
{
char magic[4];
- /* Check first 4 bytes of the image to decide if it is UNIF or iNES */
- /* Unfortunately, many .unf files have been released as .nes, so we cannot rely on extensions only */
+ // Check first 4 bytes of the image to decide if it is UNIF or iNES
+ // Unfortunately, many .unf files have been released as .nes, so we cannot rely on extensions only
fread(magic, 4);
- if ((magic[0] == 'N') && (magic[1] == 'E') && (magic[2] == 'S')) /* If header starts with 'NES' it is iNES */
+ if ((magic[0] == 'N') && (magic[1] == 'E') && (magic[2] == 'S')) // If header starts with 'NES' it is iNES
{
if (length() <= 0x10)
{
@@ -849,7 +766,7 @@ image_init_result nes_cart_slot_device::call_load()
call_load_ines();
}
- else if ((magic[0] == 'U') && (magic[1] == 'N') && (magic[2] == 'I') && (magic[3] == 'F')) /* If header starts with 'UNIF' it is UNIF */
+ else if ((magic[0] == 'U') && (magic[1] == 'N') && (magic[2] == 'I') && (magic[3] == 'F')) // If header starts with 'UNIF' it is UNIF
{
if (length() <= 0x20)
{
diff --git a/src/devices/bus/nes/nes_slot.h b/src/devices/bus/nes/nes_slot.h
index 8c0b6efa3ce..5ae61d5a643 100644
--- a/src/devices/bus/nes/nes_slot.h
+++ b/src/devices/bus/nes/nes_slot.h
@@ -170,7 +170,6 @@ enum
#define CART_NTRAM 4
-#define PPU_MIRROR_NONE 0
#define PPU_MIRROR_VERT 1
#define PPU_MIRROR_HORZ 2
#define PPU_MIRROR_HIGH 3
@@ -334,7 +333,6 @@ public:
// CHR
int m_chr_source; // global source for the 8 VROM banks
- inline void chr_sanity_check(int source);
//these were previously called chr_map. they are a quick banking structure,
//because some of these change multiple times per scanline!
@@ -346,24 +344,27 @@ public:
uint32_t m_vram_chunks;
// CHR helpers
- void chr8(int bank, int source);
- void chr4_x(int start, int bank, int source);
- void chr4_0(int bank, int source) { chr4_x(0, bank, source); }
- void chr4_4(int bank, int source) { chr4_x(4, bank, source); }
- void chr2_x(int start, int bank, int source);
- void chr2_0(int bank, int source) { chr2_x(0, bank, source); }
- void chr2_2(int bank, int source) { chr2_x(2, bank, source); }
- void chr2_4(int bank, int source) { chr2_x(4, bank, source); }
- void chr2_6(int bank, int source) { chr2_x(6, bank, source); }
- void chr1_x(int start, int bank, int source);
- void chr1_0(int bank, int source) { chr1_x(0, bank, source); }
- void chr1_1(int bank, int source) { chr1_x(1, bank, source); }
- void chr1_2(int bank, int source) { chr1_x(2, bank, source); }
- void chr1_3(int bank, int source) { chr1_x(3, bank, source); }
- void chr1_4(int bank, int source) { chr1_x(4, bank, source); }
- void chr1_5(int bank, int source) { chr1_x(5, bank, source); }
- void chr1_6(int bank, int source) { chr1_x(6, bank, source); }
- void chr1_7(int bank, int source) { chr1_x(7, bank, source); }
+private:
+ void bank_chr(int shift, int start, int bank, int source);
+public:
+ void chr8(int bank, int source) { bank_chr(3, 0, bank, source); }
+ void chr4_x(int start, int bank, int source) { bank_chr(2, start, bank, source); }
+ void chr4_0(int bank, int source) { bank_chr(2, 0, bank, source); }
+ void chr4_4(int bank, int source) { bank_chr(2, 4, bank, source); }
+ void chr2_x(int start, int bank, int source) { bank_chr(1, start, bank, source); }
+ void chr2_0(int bank, int source) { bank_chr(1, 0, bank, source); }
+ void chr2_2(int bank, int source) { bank_chr(1, 2, bank, source); }
+ void chr2_4(int bank, int source) { bank_chr(1, 4, bank, source); }
+ void chr2_6(int bank, int source) { bank_chr(1, 6, bank, source); }
+ void chr1_x(int start, int bank, int source) { bank_chr(0, start, bank, source); }
+ void chr1_0(int bank, int source) { bank_chr(0, 0, bank, source); }
+ void chr1_1(int bank, int source) { bank_chr(0, 1, bank, source); }
+ void chr1_2(int bank, int source) { bank_chr(0, 2, bank, source); }
+ void chr1_3(int bank, int source) { bank_chr(0, 3, bank, source); }
+ void chr1_4(int bank, int source) { bank_chr(0, 4, bank, source); }
+ void chr1_5(int bank, int source) { bank_chr(0, 5, bank, source); }
+ void chr1_6(int bank, int source) { bank_chr(0, 6, bank, source); }
+ void chr1_7(int bank, int source) { bank_chr(0, 7, bank, source); }
// NameTable & Mirroring