// Core SPC emulation: CPU, timers, SMP registers, memory // snes_spc 0.9.0. http://www.slack.net/~ant/ #include "Snes_Spc.h" #include <string.h> /* Copyright (C) 2004-2007 Shay Green. This module is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This module is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this module; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "blargg_source.h" #define RAM (m.ram.ram) #define REGS (m.smp_regs [0]) #define REGS_IN (m.smp_regs [1]) // (n ? n : 256) #define IF_0_THEN_256( n ) ((uint8_t) ((n) - 1) + 1) // Note: SPC_MORE_ACCURACY exists mainly so I can run my validation tests, which // do crazy echo buffer accesses. #ifndef SPC_MORE_ACCURACY #define SPC_MORE_ACCURACY 0 #endif #ifdef BLARGG_ENABLE_OPTIMIZER #include BLARGG_ENABLE_OPTIMIZER #endif //// Timers #if SPC_DISABLE_TEMPO #define TIMER_DIV( t, n ) ((n) >> t->prescaler) #define TIMER_MUL( t, n ) ((n) << t->prescaler) #else #define TIMER_DIV( t, n ) ((n) / t->prescaler) #define TIMER_MUL( t, n ) ((n) * t->prescaler) #endif Snes_Spc::Timer* Snes_Spc::run_timer_( Timer* t, rel_time_t time ) { int elapsed = TIMER_DIV( t, time - t->next_time ) + 1; t->next_time += TIMER_MUL( t, elapsed ); if ( t->enabled ) { int remain = IF_0_THEN_256( t->period - t->divider ); int divider = t->divider + elapsed; int over = elapsed - remain; if ( over >= 0 ) { int n = over / t->period; t->counter = (t->counter + 1 + n) & 0x0F; divider = over - n * t->period; } t->divider = (uint8_t) divider; } return t; } inline Snes_Spc::Timer* Snes_Spc::run_timer( Timer* t, rel_time_t time ) { if ( time >= t->next_time ) t = run_timer_( t, time ); return t; } //// ROM void Snes_Spc::enable_rom( int enable ) { if ( m.rom_enabled != enable ) { m.rom_enabled = enable; if ( enable ) memcpy( m.hi_ram, &RAM [rom_addr], sizeof m.hi_ram ); memcpy( &RAM [rom_addr], (enable ? m.rom : m.hi_ram), rom_size ); // TODO: ROM can still get overwritten when DSP writes to echo buffer } } //// DSP #if SPC_LESS_ACCURATE int const max_reg_time = 29; signed char const Snes_Spc::reg_times_ [256] = { -1, 0,-11,-10,-15,-11, -2, -2, 4, 3, 14, 14, 26, 26, 14, 22, 2, 3, 0, 1,-12, 0, 1, 1, 7, 6, 14, 14, 27, 14, 14, 23, 5, 6, 3, 4, -1, 3, 4, 4, 10, 9, 14, 14, 26, -5, 14, 23, 8, 9, 6, 7, 2, 6, 7, 7, 13, 12, 14, 14, 27, -4, 14, 24, 11, 12, 9, 10, 5, 9, 10, 10, 16, 15, 14, 14, -2, -4, 14, 24, 14, 15, 12, 13, 8, 12, 13, 13, 19, 18, 14, 14, -2,-36, 14, 24, 17, 18, 15, 16, 11, 15, 16, 16, 22, 21, 14, 14, 28, -3, 14, 25, 20, 21, 18, 19, 14, 18, 19, 19, 25, 24, 14, 14, 14, 29, 14, 25, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, }; #define RUN_DSP( time, offset ) \ int count = (time) - (offset) - m.dsp_time;\ if ( count >= 0 )\ {\ int clock_count = (count & ~(clocks_per_sample - 1)) + clocks_per_sample;\ m.dsp_time += clock_count;\ dsp.run( clock_count );\ } #else #define RUN_DSP( time, offset ) \ {\ int count = (time) - m.dsp_time;\ if ( !SPC_MORE_ACCURACY || count )\ {\ assert( count > 0 );\ m.dsp_time = (time);\ dsp.run( count );\ }\ } #endif int Snes_Spc::dsp_read( rel_time_t time ) { RUN_DSP( time, reg_times [REGS [r_dspaddr] & 0x7F] ); int result = dsp.read( REGS [r_dspaddr] & 0x7F ); #ifdef SPC_DSP_READ_HOOK SPC_DSP_READ_HOOK( spc_time + time, (REGS [r_dspaddr] & 0x7F), result ); #endif return result; } inline void Snes_Spc::dsp_write( int data, rel_time_t time ) { RUN_DSP( time, reg_times [REGS [r_dspaddr]] ) #if SPC_LESS_ACCURATE else if ( m.dsp_time == skipping_time ) { int r = REGS [r_dspaddr]; if ( r == Spc_Dsp::r_kon ) m.skipped_kon |= data & ~dsp.read( Spc_Dsp::r_koff ); if ( r == Spc_Dsp::r_koff ) { m.skipped_koff |= data; m.skipped_kon &= ~data; } } #endif #ifdef SPC_DSP_WRITE_HOOK SPC_DSP_WRITE_HOOK( m.spc_time + time, REGS [r_dspaddr], (uint8_t) data ); #endif if ( REGS [r_dspaddr] <= 0x7F ) dsp.write( REGS [r_dspaddr], data ); else if ( !SPC_MORE_ACCURACY ) dprintf( "SPC wrote to DSP register > $7F\n" ); } //// Memory access extras #if SPC_MORE_ACCURACY #define MEM_ACCESS( time, addr ) \ {\ if ( time >= m.dsp_time )\ {\ RUN_DSP( time, max_reg_time );\ }\ } #elif !defined (NDEBUG) // Debug-only check for read/write within echo buffer, since this might result in // inaccurate emulation due to the DSP not being caught up to the present. bool Snes_Spc::check_echo_access( int addr ) { if ( !(dsp.read( Spc_Dsp::r_flg ) & 0x20) ) { int start = 0x100 * dsp.read( Spc_Dsp::r_esa ); int size = 0x800 * (dsp.read( Spc_Dsp::r_edl ) & 0x0F); int end = start + (size ? size : 4); if ( start <= addr && addr < end ) { if ( !m.echo_accessed ) { m.echo_accessed = 1; return true; } } } return false; } #define MEM_ACCESS( time, addr ) check( !check_echo_access( (uint16_t) addr ) ); #else #define MEM_ACCESS( time, addr ) #endif //// CPU write #if SPC_MORE_ACCURACY static unsigned char const glitch_probs [3] [256] = { 0xC3,0x92,0x5B,0x1C,0xD1,0x92,0x5B,0x1C,0xDB,0x9C,0x72,0x18,0xCD,0x5C,0x38,0x0B, 0xE1,0x9C,0x74,0x17,0xCF,0x75,0x45,0x0C,0xCF,0x6E,0x4A,0x0D,0xA3,0x3A,0x1D,0x08, 0xDB,0xA0,0x82,0x19,0xD9,0x73,0x3C,0x0E,0xCB,0x76,0x52,0x0B,0xA5,0x46,0x1D,0x09, 0xDA,0x74,0x55,0x0F,0xA2,0x3F,0x21,0x05,0x9A,0x40,0x20,0x07,0x63,0x1E,0x10,0x01, 0xDF,0xA9,0x85,0x1D,0xD3,0x84,0x4B,0x0E,0xCF,0x6F,0x49,0x0F,0xB3,0x48,0x1E,0x05, 0xD8,0x77,0x52,0x12,0xB7,0x49,0x23,0x06,0xAA,0x45,0x28,0x07,0x7D,0x28,0x0F,0x07, 0xCC,0x7B,0x4A,0x0E,0xB2,0x4F,0x24,0x07,0xAD,0x43,0x2C,0x06,0x86,0x29,0x11,0x07, 0xAE,0x48,0x1F,0x0A,0x76,0x21,0x19,0x05,0x76,0x21,0x14,0x05,0x44,0x11,0x0B,0x01, 0xE7,0xAD,0x96,0x23,0xDC,0x86,0x59,0x0E,0xDC,0x7C,0x5F,0x15,0xBB,0x53,0x2E,0x09, 0xD6,0x7C,0x4A,0x16,0xBB,0x4A,0x25,0x08,0xB3,0x4F,0x28,0x0B,0x8E,0x23,0x15,0x08, 0xCF,0x7F,0x57,0x11,0xB5,0x4A,0x23,0x0A,0xAA,0x42,0x28,0x05,0x7D,0x22,0x12,0x03, 0xA6,0x49,0x28,0x09,0x82,0x2B,0x0D,0x04,0x7A,0x20,0x0F,0x04,0x3D,0x0F,0x09,0x03, 0xD1,0x7C,0x4C,0x0F,0xAF,0x4E,0x21,0x09,0xA8,0x46,0x2A,0x07,0x85,0x1F,0x0E,0x07, 0xA6,0x3F,0x26,0x07,0x7C,0x24,0x14,0x07,0x78,0x22,0x16,0x04,0x46,0x12,0x0A,0x02, 0xA6,0x41,0x2C,0x0A,0x7E,0x28,0x11,0x05,0x73,0x1B,0x14,0x05,0x3D,0x11,0x0A,0x02, 0x70,0x22,0x17,0x05,0x48,0x13,0x08,0x03,0x3C,0x07,0x0D,0x07,0x26,0x07,0x06,0x01, 0xE0,0x9F,0xDA,0x7C,0x4F,0x18,0x28,0x0D,0xE9,0x9F,0xDA,0x7C,0x4F,0x18,0x1F,0x07, 0xE6,0x97,0xD8,0x72,0x64,0x13,0x26,0x09,0xDC,0x67,0xA9,0x38,0x21,0x07,0x15,0x06, 0xE9,0x91,0xD2,0x6B,0x63,0x14,0x2B,0x0E,0xD6,0x61,0xB7,0x41,0x2B,0x0E,0x10,0x09, 0xCF,0x59,0xB0,0x2F,0x35,0x08,0x0F,0x07,0xB6,0x30,0x7A,0x21,0x17,0x07,0x09,0x03, 0xE7,0xA3,0xE5,0x6B,0x65,0x1F,0x34,0x09,0xD8,0x6B,0xBE,0x45,0x27,0x07,0x10,0x07, 0xDA,0x54,0xB1,0x39,0x2E,0x0E,0x17,0x08,0xA9,0x3C,0x86,0x22,0x16,0x06,0x07,0x03, 0xD4,0x51,0xBC,0x3D,0x38,0x0A,0x13,0x06,0xB2,0x37,0x79,0x1C,0x17,0x05,0x0E,0x06, 0xA7,0x31,0x74,0x1C,0x11,0x06,0x0C,0x02,0x6D,0x1A,0x38,0x10,0x0B,0x05,0x06,0x03, 0xEB,0x9A,0xE1,0x7A,0x6F,0x13,0x34,0x0E,0xE6,0x75,0xC5,0x45,0x3E,0x0B,0x1A,0x05, 0xD8,0x63,0xC1,0x40,0x3C,0x1B,0x19,0x06,0xB3,0x42,0x83,0x29,0x18,0x0A,0x08,0x04, 0xD4,0x58,0xBA,0x43,0x3F,0x0A,0x1F,0x09,0xB1,0x33,0x8A,0x1F,0x1F,0x06,0x0D,0x05, 0xAF,0x3C,0x7A,0x1F,0x16,0x08,0x0A,0x01,0x72,0x1B,0x52,0x0D,0x0B,0x09,0x06,0x01, 0xCF,0x63,0xB7,0x47,0x40,0x10,0x14,0x06,0xC0,0x41,0x96,0x20,0x1C,0x09,0x10,0x05, 0xA6,0x35,0x82,0x1A,0x20,0x0C,0x0E,0x04,0x80,0x1F,0x53,0x0F,0x0B,0x02,0x06,0x01, 0xA6,0x31,0x81,0x1B,0x1D,0x01,0x08,0x08,0x7B,0x20,0x4D,0x19,0x0E,0x05,0x07,0x03, 0x6B,0x17,0x49,0x07,0x0E,0x03,0x0A,0x05,0x37,0x0B,0x1F,0x06,0x04,0x02,0x07,0x01, 0xF0,0xD6,0xED,0xAD,0xEC,0xB1,0xEB,0x79,0xAC,0x22,0x47,0x1E,0x6E,0x1B,0x32,0x0A, 0xF0,0xD6,0xEA,0xA4,0xED,0xC4,0xDE,0x82,0x98,0x1F,0x50,0x13,0x52,0x15,0x2A,0x0A, 0xF1,0xD1,0xEB,0xA2,0xEB,0xB7,0xD8,0x69,0xA2,0x1F,0x5B,0x18,0x55,0x18,0x2C,0x0A, 0xED,0xB5,0xDE,0x7E,0xE6,0x85,0xD3,0x59,0x59,0x0F,0x2C,0x09,0x24,0x07,0x15,0x09, 0xF1,0xD6,0xEA,0xA0,0xEC,0xBB,0xDA,0x77,0xA9,0x23,0x58,0x14,0x5D,0x12,0x2F,0x09, 0xF1,0xC1,0xE3,0x86,0xE4,0x87,0xD2,0x4E,0x68,0x15,0x26,0x0B,0x27,0x09,0x15,0x02, 0xEE,0xA6,0xE0,0x5C,0xE0,0x77,0xC3,0x41,0x67,0x1B,0x3C,0x07,0x2A,0x06,0x19,0x07, 0xE4,0x75,0xC6,0x43,0xCC,0x50,0x95,0x23,0x35,0x09,0x14,0x04,0x15,0x05,0x0B,0x04, 0xEE,0xD6,0xED,0xAD,0xEC,0xB1,0xEB,0x79,0xAC,0x22,0x56,0x14,0x5A,0x12,0x26,0x0A, 0xEE,0xBB,0xE7,0x7E,0xE9,0x8D,0xCB,0x49,0x67,0x11,0x34,0x07,0x2B,0x0B,0x14,0x07, 0xED,0xA7,0xE5,0x76,0xE3,0x7E,0xC4,0x4B,0x77,0x14,0x34,0x08,0x27,0x07,0x14,0x04, 0xE7,0x8B,0xD2,0x4C,0xCA,0x56,0x9E,0x31,0x36,0x0C,0x11,0x07,0x14,0x04,0x0A,0x02, 0xF0,0x9B,0xEA,0x6F,0xE5,0x81,0xC4,0x43,0x74,0x10,0x30,0x0B,0x2D,0x08,0x1B,0x06, 0xE6,0x83,0xCA,0x48,0xD9,0x56,0xA7,0x23,0x3B,0x09,0x12,0x09,0x15,0x07,0x0A,0x03, 0xE5,0x5F,0xCB,0x3C,0xCF,0x48,0x91,0x22,0x31,0x0A,0x17,0x08,0x15,0x04,0x0D,0x02, 0xD1,0x43,0x91,0x20,0xA9,0x2D,0x54,0x12,0x17,0x07,0x09,0x02,0x0C,0x04,0x05,0x03, }; #endif // divided into multiple functions to keep rarely-used functionality separate // so often-used functionality can be optimized better by compiler // If write isn't preceded by read, data has this added to it int const no_read_before_write = 0x2000; void Snes_Spc::cpu_write_smp_reg_( int data, rel_time_t time, int addr ) { switch ( addr ) { case r_t0target: case r_t1target: case r_t2target: { Timer* t = &m.timers [addr - r_t0target]; int period = IF_0_THEN_256( data ); if ( t->period != period ) { t = run_timer( t, time ); #if SPC_MORE_ACCURACY // Insane behavior when target is written just after counter is // clocked and counter matches new period and new period isn't 1, 2, 4, or 8 if ( t->divider == (period & 0xFF) && t->next_time == time + TIMER_MUL( t, 1 ) && ((period - 1) | ~0x0F) & period ) { //dprintf( "SPC pathological timer target write\n" ); // If the period is 3, 5, or 9, there's a probability this behavior won't occur, // based on the previous period int prob = 0xFF; int old_period = t->period & 0xFF; if ( period == 3 ) prob = glitch_probs [0] [old_period]; if ( period == 5 ) prob = glitch_probs [1] [old_period]; if ( period == 9 ) prob = glitch_probs [2] [old_period]; // The glitch suppresses incrementing of one of the counter bits, based on // the lowest set bit in the new period int b = 1; while ( !(period & b) ) b <<= 1; if ( (rand() >> 4 & 0xFF) <= prob ) t->divider = (t->divider - b) & 0xFF; } #endif t->period = period; } break; } case r_t0out: case r_t1out: case r_t2out: if ( !SPC_MORE_ACCURACY ) dprintf( "SPC wrote to counter %d\n", (int) addr - r_t0out ); if ( data < no_read_before_write / 2 ) run_timer( &m.timers [addr - r_t0out], time - 1 )->counter = 0; break; // Registers that act like RAM case 0x8: case 0x9: REGS_IN [addr] = (uint8_t) data; break; case r_test: if ( (uint8_t) data != 0x0A ) dprintf( "SPC wrote to test register\n" ); break; case r_control: // port clears if ( data & 0x10 ) { REGS_IN [r_cpuio0] = 0; REGS_IN [r_cpuio1] = 0; } if ( data & 0x20 ) { REGS_IN [r_cpuio2] = 0; REGS_IN [r_cpuio3] = 0; } // timers { for ( int i = 0; i < timer_count; i++ ) { Timer* t = &m.timers [i]; int enabled = data >> i & 1; if ( t->enabled != enabled ) { t = run_timer( t, time ); t->enabled = enabled; if ( enabled ) { t->divider = 0; t->counter = 0; } } } } enable_rom( data & 0x80 ); break; } } void Snes_Spc::cpu_write_smp_reg( int data, rel_time_t time, int addr ) { if ( addr == r_dspdata ) // 99% dsp_write( data, time ); else cpu_write_smp_reg_( data, time, addr ); } void Snes_Spc::cpu_write_high( int data, int i, rel_time_t time ) { if ( i < rom_size ) { m.hi_ram [i] = (uint8_t) data; if ( m.rom_enabled ) RAM [i + rom_addr] = m.rom [i]; // restore overwritten ROM } else { assert( RAM [i + rom_addr] == (uint8_t) data ); RAM [i + rom_addr] = cpu_pad_fill; // restore overwritten padding cpu_write( data, i + rom_addr - 0x10000, time ); } } int const bits_in_int = CHAR_BIT * sizeof (int); void Snes_Spc::cpu_write( int data, int addr, rel_time_t time ) { MEM_ACCESS( time, addr ) // RAM RAM [addr] = (uint8_t) data; int reg = addr - 0xF0; if ( reg >= 0 ) // 64% { // $F0-$FF if ( reg < reg_count ) // 87% { REGS [reg] = (uint8_t) data; // Ports #ifdef SPC_PORT_WRITE_HOOK if ( (unsigned) (reg - r_cpuio0) < port_count ) SPC_PORT_WRITE_HOOK( m.spc_time + time, (reg - r_cpuio0), (uint8_t) data, ®S [r_cpuio0] ); #endif // Registers other than $F2 and $F4-$F7 //if ( reg != 2 && reg != 4 && reg != 5 && reg != 6 && reg != 7 ) // TODO: this is a bit on the fragile side if ( ((~0x2F00 << (bits_in_int - 16)) << reg) < 0 ) // 36% cpu_write_smp_reg( data, time, reg ); } // High mem/address wrap-around else { reg -= rom_addr - 0xF0; if ( reg >= 0 ) // 1% in IPL ROM area or address wrapped around cpu_write_high( data, reg, time ); } } } //// CPU read inline int Snes_Spc::cpu_read_smp_reg( int reg, rel_time_t time ) { int result = REGS_IN [reg]; reg -= r_dspaddr; // DSP addr and data if ( (unsigned) reg <= 1 ) // 4% 0xF2 and 0xF3 { result = REGS [r_dspaddr]; if ( (unsigned) reg == 1 ) result = dsp_read( time ); // 0xF3 } return result; } int Snes_Spc::cpu_read( int addr, rel_time_t time ) { MEM_ACCESS( time, addr ) // RAM int result = RAM [addr]; int reg = addr - 0xF0; if ( reg >= 0 ) // 40% { reg -= 0x10; if ( (unsigned) reg >= 0xFF00 ) // 21% { reg += 0x10 - r_t0out; // Timers if ( (unsigned) reg < timer_count ) // 90% { Timer* t = &m.timers [reg]; if ( time >= t->next_time ) t = run_timer_( t, time ); result = t->counter; t->counter = 0; } // Other registers else if ( reg < 0 ) // 10% { result = cpu_read_smp_reg( reg + r_t0out, time ); } else // 1% { assert( reg + (r_t0out + 0xF0 - 0x10000) < 0x100 ); result = cpu_read( reg + (r_t0out + 0xF0 - 0x10000), time ); } } } return result; } //// Run // Prefix and suffix for CPU emulator function #define SPC_CPU_RUN_FUNC \ BOOST::uint8_t* Snes_Spc::run_until_( time_t end_time )\ {\ rel_time_t rel_time = m.spc_time - end_time;\ assert( rel_time <= 0 );\ m.spc_time = end_time;\ m.dsp_time += rel_time;\ m.timers [0].next_time += rel_time;\ m.timers [1].next_time += rel_time;\ m.timers [2].next_time += rel_time; #define SPC_CPU_RUN_FUNC_END \ m.spc_time += rel_time;\ m.dsp_time -= rel_time;\ m.timers [0].next_time -= rel_time;\ m.timers [1].next_time -= rel_time;\ m.timers [2].next_time -= rel_time;\ assert( m.spc_time <= end_time );\ return ®S [r_cpuio0];\ } int const cpu_lag_max = 12 - 1; // DIV YA,X takes 12 clocks void Snes_Spc::end_frame( time_t end_time ) { // Catch CPU up to as close to end as possible. If final instruction // would exceed end, does NOT execute it and leaves m.spc_time < end. if ( end_time > m.spc_time ) run_until_( end_time ); m.spc_time -= end_time; m.extra_clocks += end_time; // Greatest number of clocks early that emulation can stop early due to // not being able to execute current instruction without going over // allowed time. assert( -cpu_lag_max <= m.spc_time && m.spc_time <= 0 ); // Catch timers up to CPU for ( int i = 0; i < timer_count; i++ ) run_timer( &m.timers [i], 0 ); // Catch DSP up to CPU if ( m.dsp_time < 0 ) { RUN_DSP( 0, max_reg_time ); } // Save any extra samples beyond what should be generated if ( m.buf_begin ) save_extra(); } // Inclusion here allows static memory access functions and better optimization #include "Spc_Cpu.h"