diff options
Diffstat (limited to 'contrib/nosefart/nes6502.c')
| -rw-r--r-- | contrib/nosefart/nes6502.c | 222 |
1 files changed, 200 insertions, 22 deletions
diff --git a/contrib/nosefart/nes6502.c b/contrib/nosefart/nes6502.c index f1ca80af4..d84bae912 100644 --- a/contrib/nosefart/nes6502.c +++ b/contrib/nosefart/nes6502.c @@ -1117,8 +1117,17 @@ */ /* register push/pull */ -#define PUSH(value) stack_page[S--] = (uint8) (value) -#define PULL() stack_page[++S] +#ifdef NES6502_MEM_ACCESS_CTRL + +# define PUSH(value) stack_push((S--),(value)) +# define PULL() stack_pull((++S)) + +#else + +# define PUSH(value) stack_page[S--] = (uint8) (value) +# define PULL() stack_page[++S] + +#endif /* #ifdef NES6502_MEM_ACCESS_CTRL */ /* Sets the Z and N flags based on given data, taken from precomputed table */ #define SET_NZ_FLAGS(value) P &= ~(N_FLAG | Z_FLAG); \ @@ -1166,50 +1175,194 @@ static uint8 *nes6502_banks[NES6502_NUMBANKS]; static uint8 *ram = NULL; static uint8 *stack_page = NULL; +/* access flag for memory + * $$$ ben : I add this for the playing time calculation. + * Only if compiled with NES6502_MEM_ACCESS. + */ +#ifdef NES6502_MEM_ACCESS_CTRL + +uint8 *acc_nes6502_banks[NES6502_NUMBANKS]; +static uint8 *acc_ram = NULL; +static uint8 *acc_stack_page = NULL; +uint8 nes6502_mem_access = 0; + +/* $$$ ben : + * Set memory access check flags, and store ORed frame global check + * for music time calculation. + */ +static void chk_mem_access(uint8 * access, int flags) +{ + uint8 oldchk = * access; + if ((oldchk&flags) != flags) { + nes6502_mem_access |= flags; + *access = oldchk|flags; + } +} + +INLINE void stack_push(uint8 s, uint8 v) +{ + chk_mem_access(acc_stack_page+s, NES6502_WRITE_ACCESS); + stack_page[s] = v; +} + +INLINE uint8 stack_pull(uint8 s) +{ + chk_mem_access(acc_stack_page+s, NES6502_READ_ACCESS); + return stack_page[s]; +} + +INLINE uint8 zp_read(register uint32 addr) +{ + chk_mem_access(acc_ram+addr, NES6502_READ_ACCESS); + return ram[addr]; +} + +INLINE void zp_write(register uint32 addr, uint8 v) +{ + chk_mem_access(acc_ram+addr, NES6502_WRITE_ACCESS); + ram[addr] = v; +} + +#define ZP_READ(addr) zp_read((addr)) +#define ZP_WRITE(addr, value) zp_write((addr),(value)) + +#define bank_readbyte(address) _bank_readbyte((address), NES6502_READ_ACCESS) +#define bank_readbyte_pc(address) _bank_readbyte((address), NES6502_EXE_ACCESS) + +#else +# define chk_mem_access(access, flags) /* ** Zero-page helper macros */ - #define ZP_READ(addr) ram[(addr)] #define ZP_WRITE(addr, value) ram[(addr)] = (uint8) (value) +#define bank_readbyte(address) _bank_readbyte((address)) +#define bank_readbyte_pc(address) _bank_readbyte((address)) + +#endif /* #ifdef NES6502_MEM_ACCESS_CTRL */ -INLINE uint8 bank_readbyte(register uint32 address) +#ifdef NES6502_MEM_ACCESS_CTRL +int max_access[NES6502_NUMBANKS] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; + +INLINE uint8 _bank_readbyte(register uint32 address, const uint8 flags) +#else +INLINE uint8 _bank_readbyte(register uint32 address) +#endif { ASSERT(nes6502_banks[address >> NES6502_BANKSHIFT]); + +#ifdef NES6502_MEM_ACCESS_CTRL + //printf("chk_mem_access(acc_nes6502_banks[%d] + %d, %d)\n", address>>NES6502_BANKSHIFT, address & NES6502_BANKMASK, flags); + + if((address & NES6502_BANKMASK) > max_access[address>>NES6502_BANKSHIFT]) + { + max_access[address>>NES6502_BANKSHIFT] = address & NES6502_BANKMASK; + //printf("max_access[%d] increased to %d\n", address>>NES6502_BANKSHIFT, max_access[address>>NES6502_BANKSHIFT]); + } +#endif + chk_mem_access(acc_nes6502_banks[address>>NES6502_BANKSHIFT] + + (address & NES6502_BANKMASK), + flags); + return nes6502_banks[address >> NES6502_BANKSHIFT][address & NES6502_BANKMASK]; } + INLINE void bank_writebyte(register uint32 address, register uint8 value) { ASSERT(nes6502_banks[address >> NES6502_BANKSHIFT]); + +#ifdef NES6502_MEM_ACCESS_CTRL + //printf("chk_mem_access(acc_nes6502_banks[%d] + %d, %d)\n", address>>NES6502_BANKSHIFT, address & NES6502_BANKMASK, NES6502_WRITE_ACCESS); + + if((address & NES6502_BANKMASK) > max_access[address>>NES6502_BANKSHIFT]) + { + max_access[address>>NES6502_BANKSHIFT] = address & NES6502_BANKMASK; + //printf("max_access[%d] increased to %d\n", address>>NES6502_BANKSHIFT, max_access[address>>NES6502_BANKSHIFT]); + } +#endif + + chk_mem_access(acc_nes6502_banks[address>>NES6502_BANKSHIFT] + + (address & NES6502_BANKMASK), + NES6502_WRITE_ACCESS); + nes6502_banks[address >> NES6502_BANKSHIFT][address & NES6502_BANKMASK] = value; } +/* Read a 16bit word */ +#define READ_SNES_16(bank,offset) \ +(\ + (offset) [ (uint8 *) (bank) ] |\ + ((unsigned int)( ((offset)+1) [ (uint8 *) (bank) ] ) << 8)\ +) + INLINE uint32 zp_address(register uint8 address) { - uint8 *x = ram + address; - return (x[1] << 8) | x[0]; + chk_mem_access(acc_ram+address, NES6502_READ_ACCESS); + chk_mem_access(acc_ram+address+1, NES6502_READ_ACCESS); + +#if defined (HOST_LITTLE_ENDIAN) && defined(HOST_UNALIGN_WORD) + /* TODO: this fails if src address is $xFFF */ + /* TODO: this fails if host architecture doesn't support byte alignment */ + /* $$$ ben : DONE */ + return (uint32) (*(uint16 *)(ram + address)); +#elif defined(TARGET_CPU_PPC) + return __lhbrx(ram, address); +#else + return READ_SNES_16(ram,address); +/* uint32 x = (uint32) *(uint16 *)(ram + address); */ +/* return (x << 8) | (x >> 8); */ +//#endif /* TARGET_CPU_PPC */ +#endif /* HOST_LITTLE_ENDIAN */ } INLINE uint32 bank_readaddress(register uint32 address) { - uint8 *x = nes6502_banks[address >> NES6502_BANKSHIFT] + (address & NES6502_BANKMASK); - return (x[1] << 8) | x[0]; + +#ifdef NES6502_MEM_ACCESS_CTRL + { + const unsigned int offset = address & NES6502_BANKMASK; + uint8 * addr = acc_nes6502_banks[address >> NES6502_BANKSHIFT]; + chk_mem_access(addr+offset+0, NES6502_READ_ACCESS); + chk_mem_access(addr+offset+1, NES6502_READ_ACCESS); + } +#endif + +#if defined (HOST_LITTLE_ENDIAN) && defined(HOST_UNALIGN_WORD) + /* TODO: this fails if src address is $xFFF */ + /* TODO: this fails if host architecture doesn't support byte alignment */ + /* $$$ ben : DONE */ + return (uint32) (*(uint16 *)(nes6502_banks[address >> NES6502_BANKSHIFT] + (address & NES6502_BANKMASK))); +#elif defined(TARGET_CPU_PPC) + return __lhbrx(nes6502_banks[address >> NES6502_BANKSHIFT], address & NES6502_BANKMASK); +#else + { + const unsigned int offset = address & NES6502_BANKMASK; + return READ_SNES_16(nes6502_banks[address >> NES6502_BANKSHIFT], offset); + } +/* uint32 x = (uint32) *(uint16 *)(nes6502_banks[address >> NES6502_BANKSHIFT] + (address & NES6502_BANKMASK)); */ +/* return (x << 8) | (x >> 8); */ +//#endif /* TARGET_CPU_PPC */ +#endif /* HOST_LITTLE_ENDIAN */ } + /* read a byte of 6502 memory */ static uint8 mem_read(uint32 address) { /* TODO: following cases are N2A03-specific */ /* RAM */ - if (address < 0x800) - return ram[address]; + if (address < 0x800) { + chk_mem_access(acc_ram + address, NES6502_READ_ACCESS); + return ram[address]; + } /* always paged memory */ // else if (address >= 0x6000) - else if (address >= 0x8000) - return bank_readbyte(address); + else if (address >= 0x8000) { + return bank_readbyte(address); + } /* check memory range handlers */ else { @@ -1230,6 +1383,7 @@ static void mem_write(uint32 address, uint8 value) /* RAM */ if (address < 0x800) { + chk_mem_access(acc_ram + address, NES6502_WRITE_ACCESS); ram[address] = value; return; } @@ -1258,11 +1412,19 @@ void nes6502_setcontext(nes6502_context *cpu) ASSERT(cpu); /* Set the page pointers */ - for (loop = 0; loop < NES6502_NUMBANKS; loop++) + for (loop = 0; loop < NES6502_NUMBANKS; loop++) { nes6502_banks[loop] = cpu->mem_page[loop]; +#ifdef NES6502_MEM_ACCESS_CTRL + acc_nes6502_banks[loop] = cpu->acc_mem_page[loop]; +#endif + } ram = nes6502_banks[0]; /* quicker zero-page/RAM references */ stack_page = ram + STACK_OFFSET; +#ifdef NES6502_MEM_ACCESS_CTRL + acc_ram = acc_nes6502_banks[0]; /* quicker zero-page/RAM references */ + acc_stack_page = acc_ram + STACK_OFFSET; +#endif pmem_read = cpu->read_handler; pmem_write = cpu->write_handler; @@ -1283,8 +1445,12 @@ void nes6502_getcontext(nes6502_context *cpu) int loop; /* Set the page pointers */ - for (loop = 0; loop < NES6502_NUMBANKS; loop++) + for (loop = 0; loop < NES6502_NUMBANKS; loop++) { cpu->mem_page[loop] = nes6502_banks[loop]; +#ifdef NES6502_MEM_ACCESS_CTRL + cpu->acc_mem_page[loop] = acc_nes6502_banks[loop]; +#endif + } cpu->read_handler = pmem_read; cpu->write_handler = pmem_write; @@ -1333,7 +1499,14 @@ int nes6502_execute(int remaining_cycles) GET_GLOBAL_REGS(); +#ifdef NES6502_MEM_ACCESS_CTRL + /* reset global memory access for this execute loop. */ + nes6502_mem_access = 0; +#endif + /* Continue until we run out of cycles */ + + while (remaining_cycles > 0) { instruction_cycles = 0; @@ -1373,9 +1546,10 @@ int nes6502_execute(int remaining_cycles) /* Fetch instruction */ //nes6502_disasm(PC, P, A, X, Y, S); - opcode = bank_readbyte(PC++); + opcode = bank_readbyte_pc(PC++); /* Execute instruction */ + switch (opcode) { case 0x00: /* BRK */ @@ -2363,16 +2537,20 @@ void nes6502_setdma(int cycles) dma_cycles += cycles; } +#ifdef NES6502_MEM_ACCESS_CTRL +void nes6502_chk_mem_access(uint8 * access, int flags) +{ + chk_mem_access(access, flags); +} +#endif + /* ** $Log: nes6502.c,v $ -** Revision 1.2 2003/01/09 19:50:03 jkeil -** NSF audio files were crashing on SPARC. -** -** - Define the correct HOST_ENDIAN for SPARC -** - remove unaligned memory accesses +** Revision 1.2 2003/05/01 22:34:19 benjihan +** New NSF plugin ** -** Revision 1.1 2003/01/08 07:04:35 tmmm -** initial import of Nosefart sources +** Revision 1.1 2003/04/08 20:53:00 ben +** Adding more files... ** ** Revision 1.6 2000/07/04 04:50:07 matt ** minor change to includes |