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cog/Frameworks/GME/gme/Hes_Cpu_run.h

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Updated Game_Music_Emu to latest VGMPlay branch
2015-11-27 10:02:41 +00:00
// $package. http://www.slack.net/~ant/
#if 0
/* Define these macros in the source file before #including this file.
- Parameters might be expressions, so they are best evaluated only once,
though they NEVER have side-effects, so multiple evaluation is OK.
- Output parameters might be a multiple-assignment expression like "a=x",
so they must NOT be parenthesized.
- Except where noted, time() and related functions will NOT work
correctly inside a macro. TIME() is always correct, and FLUSH_TIME() and
CACHE_TIME() allow the time changing functions to work.
- Macros "returning" void may use a {} statement block. */
// 0 <= addr <= 0xFFFF + page_size
// time functions can be used
int READ_MEM( addr_t );
void WRITE_MEM( addr_t, int data );
// 0 <= addr <= 0x1FF
int READ_LOW( addr_t );
void WRITE_LOW( addr_t, int data );
// 0 <= addr <= 0xFFFF + page_size
// Used by common instructions.
int READ_FAST( addr_t, int& out );
void WRITE_FAST( addr_t, int data );
// 0 <= addr <= 2
// ST0, ST1, ST2 instructions
void WRITE_VDP( int addr, int data );
// The following can be used within macros:
// Current time
time_t TIME();
// Allows use of time functions
void FLUSH_TIME();
// Must be used before end of macro if FLUSH_TIME() was used earlier
void CACHE_TIME();
// Configuration (optional; commented behavior if defined)
// Expanded just before beginning of code, to help debugger
#define CPU_BEGIN void my_run_cpu() {
#endif
/* Copyright (C) 2003-2008 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 */
// TODO: support T flag, including clearing it at appropriate times?
// all zero-page should really use whatever is at page 1, but that would
// reduce efficiency quite a bit
int const ram_addr = 0x2000;
void Hes_Cpu::reset()
{
check( cpu_state == &cpu_state_ );
cpu_state = &cpu_state_;
cpu_state_.time = 0;
cpu_state_.base = 0;
irq_time_ = future_time;
end_time_ = future_time;
r.flags = 0x04;
r.sp = 0;
r.pc = 0;
r.a = 0;
r.x = 0;
r.y = 0;
// Be sure "blargg_endian.h" has been #included
blargg_verify_byte_order();
}
// Allows MWCW debugger to step through code properly
#ifdef CPU_BEGIN
CPU_BEGIN
#endif
// Time
#define TIME() (s_time + s.base)
#define FLUSH_TIME() {s.time = s_time;}
#define CACHE_TIME() {s_time = s.time;}
// Memory
#define READ_STACK READ_LOW
#define WRITE_STACK WRITE_LOW
#define CODE_PAGE( addr ) s.code_map [HES_CPU_PAGE( addr )]
#define CODE_OFFSET( addr ) HES_CPU_OFFSET( addr )
#define READ_CODE( addr ) CODE_PAGE( addr ) [CODE_OFFSET( addr )]
// Stack
#define SET_SP( v ) (sp = ((v) + 1) | 0x100)
#define GET_SP() ((sp - 1) & 0xFF)
#define SP( o ) ((sp + (o - (o>0)*0x100)) | 0x100)
// Truncation
#define BYTE( n ) ((BOOST::uint8_t ) (n)) /* (unsigned) n & 0xFF */
#define SBYTE( n ) ((BOOST::int8_t ) (n)) /* (BYTE( n ) ^ 0x80) - 0x80 */
#define WORD( n ) ((BOOST::uint16_t) (n)) /* (unsigned) n & 0xFFFF */
// Flags with hex value for clarity when used as mask.
// Stored in indicated variable during emulation.
int const n80 = 0x80; // nz
int const v40 = 0x40; // flags
//int const t20 = 0x20;
int const b10 = 0x10;
int const d08 = 0x08; // flags
int const i04 = 0x04; // flags
int const z02 = 0x02; // nz
int const c01 = 0x01; // c
#define IS_NEG (nz & 0x8080)
#define GET_FLAGS( out ) \
{\
out = flags & (v40 | d08 | i04);\
out += ((nz >> 8) | nz) & n80;\
out += c >> 8 & c01;\
if ( !BYTE( nz ) )\
out += z02;\
}
#define SET_FLAGS( in ) \
{\
flags = in & (v40 | d08 | i04);\
c = nz = in << 8;\
nz += ~in & z02;\
}
bool illegal_encountered = false;
{
Hes_Cpu::cpu_state_t s = CPU.cpu_state_;
CPU.cpu_state = &s;
// even on x86, using s.time in place of s_time was slower
int s_time = s.time;
// registers
int pc = CPU.r.pc;
int a = CPU.r.a;
int x = CPU.r.x;
int y = CPU.r.y;
int sp;
SET_SP( CPU.r.sp );
// Flags
int flags;
int c; // carry set if (c & 0x100) != 0
int nz; // Z set if (nz & 0xFF) == 0, N set if (nz & 0x8080) != 0
{
int temp = CPU.r.flags;
SET_FLAGS( temp );
}
loop:
#ifndef NDEBUG
{
time_t correct = CPU.end_time_;
if ( !(flags & i04) && correct > CPU.irq_time_ )
correct = CPU.irq_time_;
check( s.base == correct );
/*
static int count;
if ( count == 1844 ) Debugger();
if ( s.base != correct ) dprintf( "%ld\n", count );
count++;
*/
}
#endif
// Check all values
check( (unsigned) sp - 0x100 < 0x100 );
check( (unsigned) pc < 0x10000 + 0x100 ); // +0x100 so emulator can catch wrap-around
check( (unsigned) a < 0x100 );
check( (unsigned) x < 0x100 );
check( (unsigned) y < 0x100 );
// Read instruction
byte const* instr = CODE_PAGE( pc );
int opcode;
if ( CODE_OFFSET(~0) == ~0 )
{
opcode = instr [pc];
pc++;
instr += pc;
}
else
{
instr += CODE_OFFSET( pc );
opcode = *instr++;
pc++;
}
// TODO: each reference lists slightly different timing values, ugh
static byte const clock_table [256] =
{// 0 1 2 3 4 5 6 7 8 9 A B C D E F
1,7,3, 4,6,4,6,7,3,2,2,2,7,5,7,4,// 0
2,7,7, 4,6,4,6,7,2,5,2,2,7,5,7,4,// 1
7,7,3, 4,4,4,6,7,4,2,2,2,5,5,7,4,// 2
2,7,7, 2,4,4,6,7,2,5,2,2,5,5,7,4,// 3
7,7,3, 4,8,4,6,7,3,2,2,2,4,5,7,4,// 4
2,7,7, 5,2,4,6,7,2,5,3,2,2,5,7,4,// 5
7,7,2, 2,4,4,6,7,4,2,2,2,7,5,7,4,// 6
2,7,7,17,4,4,6,7,2,5,4,2,7,5,7,4,// 7
4,7,2, 7,4,4,4,7,2,2,2,2,5,5,5,4,// 8
2,7,7, 8,4,4,4,7,2,5,2,2,5,5,5,4,// 9
2,7,2, 7,4,4,4,7,2,2,2,2,5,5,5,4,// A
2,7,7, 8,4,4,4,7,2,5,2,2,5,5,5,4,// B
2,7,2,17,4,4,6,7,2,2,2,2,5,5,7,4,// C
2,7,7,17,2,4,6,7,2,5,3,2,2,5,7,4,// D
2,7,2,17,4,4,6,7,2,2,2,2,5,5,7,4,// E
2,7,7,17,2,4,6,7,2,5,4,2,2,5,7,4 // F
}; // 0x00 was 8
// Update time
if ( s_time >= 0 )
goto out_of_time;
#ifdef HES_CPU_LOG_H
log_cpu( "new", pc - 1, opcode, instr [0], instr [1], instr [2],
instr [3], instr [4], instr [5], a, x, y );
//log_opcode( opcode );
#endif
s_time += clock_table [opcode];
int data;
data = *instr;
switch ( opcode )
{
// Macros
#define GET_MSB() (instr [1])
#define ADD_PAGE( out ) (pc++, out = data + 0x100 * GET_MSB());
#define GET_ADDR() GET_LE16( instr )
// TODO: is the penalty really always added? the original 6502 was much better
//#define PAGE_PENALTY( lsb ) (void) (s_time += (lsb) >> 8)
#define PAGE_PENALTY( lsb )
// Branch
// TODO: more efficient way to handle negative branch that wraps PC around
#define BRANCH_( cond, adj )\
{\
pc++;\
if ( !(cond) ) goto loop;\
pc = (BOOST::uint16_t) (pc + SBYTE( data ));\
s_time += adj;\
goto loop;\
}
#define BRANCH( cond ) BRANCH_( cond, 2 )
case 0xF0: // BEQ
BRANCH( !BYTE( nz ) );
case 0xD0: // BNE
BRANCH( BYTE( nz ) );
case 0x10: // BPL
BRANCH( !IS_NEG );
case 0x90: // BCC
BRANCH( !(c & 0x100) )
case 0x30: // BMI
BRANCH( IS_NEG )
case 0x50: // BVC
BRANCH( !(flags & v40) )
case 0x70: // BVS
BRANCH( flags & v40 )
case 0xB0: // BCS
BRANCH( c & 0x100 )
case 0x80: // BRA
branch_taken:
BRANCH_( true, 0 );
case 0xFF:
#ifdef IDLE_ADDR
if ( pc == IDLE_ADDR + 1 )
goto idle_done;
#endif
pc = (BOOST::uint16_t) pc;
case 0x0F: // BBRn
case 0x1F:
case 0x2F:
case 0x3F:
case 0x4F:
case 0x5F:
case 0x6F:
case 0x7F:
case 0x8F: // BBSn
case 0x9F:
case 0xAF:
case 0xBF:
case 0xCF:
case 0xDF:
case 0xEF: {
// Make two copies of bits, one negated
int t = 0x101 * READ_LOW( data );
t ^= 0xFF;
pc++;
data = GET_MSB();
BRANCH( t & (1 << (opcode >> 4)) )
}
case 0x4C: // JMP abs
pc = GET_ADDR();
goto loop;
case 0x7C: // JMP (ind+X)
data += x;
case 0x6C:{// JMP (ind)
data += 0x100 * GET_MSB();
pc = GET_LE16( &READ_CODE( data ) );
goto loop;
}
// Subroutine
case 0x44: // BSR
WRITE_STACK( SP( -1 ), pc >> 8 );
sp = SP( -2 );
WRITE_STACK( sp, pc );
goto branch_taken;
case 0x20: { // JSR
int temp = pc + 1;
pc = GET_ADDR();
WRITE_STACK( SP( -1 ), temp >> 8 );
sp = SP( -2 );
WRITE_STACK( sp, temp );
goto loop;
}
case 0x60: // RTS
pc = 1 + READ_STACK( sp );
pc += 0x100 * READ_STACK( SP( 1 ) );
sp = SP( 2 );
goto loop;
case 0x00: // BRK
goto handle_brk;
// Common
case 0xBD:{// LDA abs,X
PAGE_PENALTY( data + x );
int addr = GET_ADDR() + x;
pc += 2;
READ_FAST( addr, nz );
a = nz;
goto loop;
}
case 0x9D:{// STA abs,X
int addr = GET_ADDR() + x;
pc += 2;
WRITE_FAST( addr, a );
goto loop;
}
case 0x95: // STA zp,x
data = BYTE( data + x );
case 0x85: // STA zp
pc++;
WRITE_LOW( data, a );
goto loop;
case 0xAE:{// LDX abs
int addr = GET_ADDR();
pc += 2;
READ_FAST( addr, nz );
x = nz;
goto loop;
}
case 0xA5: // LDA zp
a = nz = READ_LOW( data );
pc++;
goto loop;
// Load/store
{
int addr;
case 0x91: // STA (ind),Y
addr = 0x100 * READ_LOW( BYTE( data + 1 ) );
addr += READ_LOW( data ) + y;
pc++;
goto sta_ptr;
case 0x81: // STA (ind,X)
data = BYTE( data + x );
case 0x92: // STA (ind)
addr = 0x100 * READ_LOW( BYTE( data + 1 ) );
addr += READ_LOW( data );
pc++;
goto sta_ptr;
case 0x99: // STA abs,Y
data += y;
case 0x8D: // STA abs
addr = data + 0x100 * GET_MSB();
pc += 2;
sta_ptr:
WRITE_FAST( addr, a );
goto loop;
}
{
int addr;
case 0xA1: // LDA (ind,X)
data = BYTE( data + x );
case 0xB2: // LDA (ind)
addr = 0x100 * READ_LOW( BYTE( data + 1 ) );
addr += READ_LOW( data );
pc++;
goto a_nz_read_addr;
case 0xB1:// LDA (ind),Y
addr = READ_LOW( data ) + y;
PAGE_PENALTY( addr );
addr += 0x100 * READ_LOW( BYTE( data + 1 ) );
pc++;
goto a_nz_read_addr;
case 0xB9: // LDA abs,Y
data += y;
PAGE_PENALTY( data );
case 0xAD: // LDA abs
addr = data + 0x100 * GET_MSB();
pc += 2;
a_nz_read_addr:
READ_FAST( addr, nz );
a = nz;
goto loop;
}
case 0xBE:{// LDX abs,y
PAGE_PENALTY( data + y );
int addr = GET_ADDR() + y;
pc += 2;
FLUSH_TIME();
x = nz = READ_MEM( addr );
CACHE_TIME();
goto loop;
}
case 0xB5: // LDA zp,x
a = nz = READ_LOW( BYTE( data + x ) );
pc++;
goto loop;
case 0xA9: // LDA #imm
pc++;
a = data;
nz = data;
goto loop;
// Bit operations
case 0x3C: // BIT abs,x
data += x;
case 0x2C:{// BIT abs
int addr;
ADD_PAGE( addr );
FLUSH_TIME();
nz = READ_MEM( addr );
CACHE_TIME();
goto bit_common;
}
case 0x34: // BIT zp,x
data = BYTE( data + x );
case 0x24: // BIT zp
data = READ_LOW( data );
case 0x89: // BIT imm
nz = data;
bit_common:
pc++;
flags = (flags & ~v40) + (nz & v40);
if ( nz & a )
goto loop; // Z should be clear, and nz must be non-zero if nz & a is
nz <<= 8; // set Z flag without affecting N flag
goto loop;
{
int addr;
case 0xB3: // TST abs,x
addr = GET_MSB() + x;
goto tst_abs;
case 0x93: // TST abs
addr = GET_MSB();
tst_abs:
addr += 0x100 * instr [2];
pc++;
FLUSH_TIME();
nz = READ_MEM( addr );
CACHE_TIME();
goto tst_common;
}
case 0xA3: // TST zp,x
nz = READ_LOW( BYTE( GET_MSB() + x ) );
goto tst_common;
case 0x83: // TST zp
nz = READ_LOW( GET_MSB() );
tst_common:
pc += 2;
flags = (flags & ~v40) + (nz & v40);
if ( nz & data )
goto loop; // Z should be clear, and nz must be non-zero if nz & data is
nz <<= 8; // set Z flag without affecting N flag
goto loop;
{
int addr;
case 0x0C: // TSB abs
case 0x1C: // TRB abs
addr = GET_ADDR();
pc++;
goto txb_addr;
// TODO: everyone lists different behaviors for the flags flags, ugh
case 0x04: // TSB zp
case 0x14: // TRB zp
addr = data + ram_addr;
txb_addr:
FLUSH_TIME();
nz = a | READ_MEM( addr );
if ( opcode & 0x10 )
nz ^= a; // bits from a will already be set, so this clears them
flags = (flags & ~v40) + (nz & v40);
pc++;
WRITE_MEM( addr, nz );
CACHE_TIME();
goto loop;
}
case 0x07: // RMBn
case 0x17:
case 0x27:
case 0x37:
case 0x47:
case 0x57:
case 0x67:
case 0x77:
pc++;
READ_LOW( data ) &= ~(1 << (opcode >> 4));
goto loop;
case 0x87: // SMBn
case 0x97:
case 0xA7:
case 0xB7:
case 0xC7:
case 0xD7:
case 0xE7:
case 0xF7:
pc++;
READ_LOW( data ) |= 1 << ((opcode >> 4) - 8);
goto loop;
// Load/store
case 0x9E: // STZ abs,x
data += x;
case 0x9C: // STZ abs
ADD_PAGE( data );
pc++;
FLUSH_TIME();
WRITE_MEM( data, 0 );
CACHE_TIME();
goto loop;
case 0x74: // STZ zp,x
data = BYTE( data + x );
case 0x64: // STZ zp
pc++;
WRITE_LOW( data, 0 );
goto loop;
case 0x94: // STY zp,x
data = BYTE( data + x );
case 0x84: // STY zp
pc++;
WRITE_LOW( data, y );
goto loop;
case 0x96: // STX zp,y
data = BYTE( data + y );
case 0x86: // STX zp
pc++;
WRITE_LOW( data, x );
goto loop;
case 0xB6: // LDX zp,y
data = BYTE( data + y );
case 0xA6: // LDX zp
data = READ_LOW( data );
case 0xA2: // LDX #imm
pc++;
x = data;
nz = data;
goto loop;
case 0xB4: // LDY zp,x
data = BYTE( data + x );
case 0xA4: // LDY zp
data = READ_LOW( data );
case 0xA0: // LDY #imm
pc++;
y = data;
nz = data;
goto loop;
case 0xBC: // LDY abs,X
data += x;
PAGE_PENALTY( data );
case 0xAC:{// LDY abs
int addr = data + 0x100 * GET_MSB();
pc += 2;
FLUSH_TIME();
y = nz = READ_MEM( addr );
CACHE_TIME();
goto loop;
}
{
int temp;
case 0x8C: // STY abs
temp = y;
if ( 0 )
case 0x8E: // STX abs
temp = x;
int addr = GET_ADDR();
pc += 2;
FLUSH_TIME();
WRITE_MEM( addr, temp );
CACHE_TIME();
goto loop;
}
// Compare
case 0xEC:{// CPX abs
int addr = GET_ADDR();
pc++;
FLUSH_TIME();
data = READ_MEM( addr );
CACHE_TIME();
goto cpx_data;
}
case 0xE4: // CPX zp
data = READ_LOW( data );
case 0xE0: // CPX #imm
cpx_data:
nz = x - data;
pc++;
c = ~nz;
nz = BYTE( nz );
goto loop;
case 0xCC:{// CPY abs
int addr = GET_ADDR();
pc++;
FLUSH_TIME();
data = READ_MEM( addr );
CACHE_TIME();
goto cpy_data;
}
case 0xC4: // CPY zp
data = READ_LOW( data );
case 0xC0: // CPY #imm
cpy_data:
nz = y - data;
pc++;
c = ~nz;
nz = BYTE( nz );
goto loop;
// Logical
#define ARITH_ADDR_MODES( op )\
case op - 0x04: /* (ind,x) */\
data = BYTE( data + x );\
case op + 0x0D: /* (ind) */\
data = 0x100 * READ_LOW( BYTE( data + 1 ) ) + READ_LOW( data );\
goto ptr##op;\
case op + 0x0C:{/* (ind),y */\
int temp = READ_LOW( data ) + y;\
PAGE_PENALTY( temp );\
data = temp + 0x100 * READ_LOW( BYTE( data + 1 ) );\
goto ptr##op;\
}\
case op + 0x10: /* zp,X */\
data = BYTE( data + x );\
case op + 0x00: /* zp */\
data = READ_LOW( data );\
goto imm##op;\
case op + 0x14: /* abs,Y */\
data += y;\
goto ind##op;\
case op + 0x18: /* abs,X */\
data += x;\
ind##op:\
PAGE_PENALTY( data );\
case op + 0x08: /* abs */\
ADD_PAGE( data );\
ptr##op:\
FLUSH_TIME();\
data = READ_MEM( data );\
CACHE_TIME();\
case op + 0x04: /* imm */\
imm##op:
ARITH_ADDR_MODES( 0xC5 ) // CMP
nz = a - data;
pc++;
c = ~nz;
nz = BYTE( nz );
goto loop;
ARITH_ADDR_MODES( 0x25 ) // AND
nz = (a &= data);
pc++;
goto loop;
ARITH_ADDR_MODES( 0x45 ) // EOR
nz = (a ^= data);
pc++;
goto loop;
ARITH_ADDR_MODES( 0x05 ) // ORA
nz = (a |= data);
pc++;
goto loop;
// Add/subtract
ARITH_ADDR_MODES( 0xE5 ) // SBC
data ^= 0xFF;
goto adc_imm;
ARITH_ADDR_MODES( 0x65 ) // ADC
adc_imm: {
if ( flags & d08 )
dprintf( "Decimal mode not supported\n" );
int carry = c >> 8 & 1;
int ov = (a ^ 0x80) + carry + SBYTE( data );
flags = (flags & ~v40) + (ov >> 2 & v40);
c = nz = a + data + carry;
pc++;
a = BYTE( nz );
goto loop;
}
// Shift/rotate
case 0x4A: // LSR A
c = 0;
case 0x6A: // ROR A
nz = c >> 1 & 0x80;
c = a << 8;
nz += a >> 1;
a = nz;
goto loop;
case 0x0A: // ASL A
nz = a << 1;
c = nz;
a = BYTE( nz );
goto loop;
case 0x2A: { // ROL A
nz = a << 1;
int temp = c >> 8 & 1;
c = nz;
nz += temp;
a = BYTE( nz );
goto loop;
}
case 0x5E: // LSR abs,X
data += x;
case 0x4E: // LSR abs
c = 0;
case 0x6E: // ROR abs
ror_abs: {
ADD_PAGE( data );
FLUSH_TIME();
int temp = READ_MEM( data );
nz = (c >> 1 & 0x80) + (temp >> 1);
c = temp << 8;
goto rotate_common;
}
case 0x3E: // ROL abs,X
data += x;
goto rol_abs;
case 0x1E: // ASL abs,X
data += x;
case 0x0E: // ASL abs
c = 0;
case 0x2E: // ROL abs
rol_abs:
ADD_PAGE( data );
nz = c >> 8 & 1;
FLUSH_TIME();
nz += (c = READ_MEM( data ) << 1);
rotate_common:
pc++;
WRITE_MEM( data, BYTE( nz ) );
CACHE_TIME();
goto loop;
case 0x7E: // ROR abs,X
data += x;
goto ror_abs;
case 0x76: // ROR zp,x
data = BYTE( data + x );
goto ror_zp;
case 0x56: // LSR zp,x
data = BYTE( data + x );
case 0x46: // LSR zp
c = 0;
case 0x66: // ROR zp
ror_zp: {
int temp = READ_LOW( data );
nz = (c >> 1 & 0x80) + (temp >> 1);
c = temp << 8;
goto write_nz_zp;
}
case 0x36: // ROL zp,x
data = BYTE( data + x );
goto rol_zp;
case 0x16: // ASL zp,x
data = BYTE( data + x );
case 0x06: // ASL zp
c = 0;
case 0x26: // ROL zp
rol_zp:
nz = c >> 8 & 1;
nz += (c = READ_LOW( data ) << 1);
goto write_nz_zp;
// Increment/decrement
#define INC_DEC( reg, n ) reg = BYTE( nz = reg + n ); goto loop;
case 0x1A: // INA
INC_DEC( a, +1 )
case 0xE8: // INX
INC_DEC( x, +1 )
case 0xC8: // INY
INC_DEC( y, +1 )
case 0x3A: // DEA
INC_DEC( a, -1 )
case 0xCA: // DEX
INC_DEC( x, -1 )
case 0x88: // DEY
INC_DEC( y, -1 )
case 0xF6: // INC zp,x
data = BYTE( data + x );
case 0xE6: // INC zp
nz = 1;
goto add_nz_zp;
case 0xD6: // DEC zp,x
data = BYTE( data + x );
case 0xC6: // DEC zp
nz = -1;
add_nz_zp:
nz += READ_LOW( data );
write_nz_zp:
pc++;
WRITE_LOW( data, nz );
goto loop;
case 0xFE: // INC abs,x
data = x + GET_ADDR();
goto inc_ptr;
case 0xEE: // INC abs
data = GET_ADDR();
inc_ptr:
nz = 1;
goto inc_common;
case 0xDE: // DEC abs,x
data = x + GET_ADDR();
goto dec_ptr;
case 0xCE: // DEC abs
data = GET_ADDR();
dec_ptr:
nz = -1;
inc_common:
FLUSH_TIME();
pc += 2;
nz += READ_MEM( data );
WRITE_MEM( data, BYTE( nz ) );
CACHE_TIME();
goto loop;
// Transfer
case 0xA8: // TAY
y = nz = a;
goto loop;
case 0x98: // TYA
a = nz = y;
goto loop;
case 0xAA: // TAX
x = nz = a;
goto loop;
case 0x8A: // TXA
a = nz = x;
goto loop;
case 0x9A: // TXS
SET_SP( x ); // verified (no flag change)
goto loop;
case 0xBA: // TSX
x = nz = GET_SP();
goto loop;
#define SWAP_REGS( r1, r2 ) {\
int t = r1;\
r1 = r2;\
r2 = t;\
goto loop;\
}
case 0x02: // SXY
SWAP_REGS( x, y );
case 0x22: // SAX
SWAP_REGS( a, x );
case 0x42: // SAY
SWAP_REGS( a, y );
case 0x62: // CLA
a = 0;
goto loop;
case 0x82: // CLX
x = 0;
goto loop;
case 0xC2: // CLY
y = 0;
goto loop;
// Stack
case 0x48: // PHA
sp = SP( -1 );
WRITE_STACK( sp, a );
goto loop;
case 0x68: // PLA
a = nz = READ_STACK( sp );
sp = SP( 1 );
goto loop;
case 0xDA: // PHX
sp = SP( -1 );
WRITE_STACK( sp, x );
goto loop;
case 0x5A: // PHY
sp = SP( -1 );
WRITE_STACK( sp, y );
goto loop;
case 0x40:{// RTI
pc = READ_STACK( SP( 1 ) );
pc += READ_STACK( SP( 2 ) ) * 0x100;
int temp = READ_STACK( sp );
sp = SP( 3 );
data = flags;
SET_FLAGS( temp );
CPU.r.flags = flags; // update externally-visible I flag
if ( (data ^ flags) & i04 )
{
time_t new_time = CPU.end_time_;
if ( !(flags & i04) && new_time > CPU.irq_time_ )
new_time = CPU.irq_time_;
int delta = s.base - new_time;
s.base = new_time;
s_time += delta;
}
goto loop;
}
case 0xFA: // PLX
x = nz = READ_STACK( sp );
sp = SP( 1 );
goto loop;
case 0x7A: // PLY
y = nz = READ_STACK( sp );
sp = SP( 1 );
goto loop;
case 0x28:{// PLP
int temp = READ_STACK( sp );
sp = SP( 1 );
int changed = flags ^ temp;
SET_FLAGS( temp );
if ( !(changed & i04) )
goto loop; // I flag didn't change
if ( flags & i04 )
goto handle_sei;
goto handle_cli;
}
case 0x08:{// PHP
int temp;
GET_FLAGS( temp );
sp = SP( -1 );
WRITE_STACK( sp, temp | b10 );
goto loop;
}
// Flags
case 0x38: // SEC
c = 0x100;
goto loop;
case 0x18: // CLC
c = 0;
goto loop;
case 0xB8: // CLV
flags &= ~v40;
goto loop;
case 0xD8: // CLD
flags &= ~d08;
goto loop;
case 0xF8: // SED
flags |= d08;
goto loop;
case 0x58: // CLI
if ( !(flags & i04) )
goto loop;
flags &= ~i04;
handle_cli: {
//dprintf( "CLI at %d\n", TIME );
CPU.r.flags = flags; // update externally-visible I flag
int delta = s.base - CPU.irq_time_;
if ( delta <= 0 )
{
if ( TIME() < CPU.irq_time_ )
goto loop;
goto delayed_cli;
}
s.base = CPU.irq_time_;
s_time += delta;
if ( s_time < 0 )
goto loop;
if ( delta >= s_time + 1 )
{
// delayed irq until after next instruction
s.base += s_time + 1;
s_time = -1;
CPU.irq_time_ = s.base; // TODO: remove, as only to satisfy debug check in loop
goto loop;
}
// TODO: implement
delayed_cli:
dprintf( "Delayed CLI not supported\n" );
goto loop;
}
case 0x78: // SEI
if ( flags & i04 )
goto loop;
flags |= i04;
handle_sei: {
CPU.r.flags = flags; // update externally-visible I flag
int delta = s.base - CPU.end_time_;
s.base = CPU.end_time_;
s_time += delta;
if ( s_time < 0 )
goto loop;
dprintf( "Delayed SEI not supported\n" );
goto loop;
}
// Special
case 0x53:{// TAM
int bits = data; // avoid using data across function call
pc++;
for ( int i = 0; i < 8; i++ )
if ( bits & (1 << i) )
SET_MMR( i, a );
goto loop;
}
case 0x43:{// TMA
pc++;
byte const* in = CPU.mmr;
do
{
if ( data & 1 )
a = *in;
in++;
}
while ( (data >>= 1) != 0 );
goto loop;
}
case 0x03: // ST0
case 0x13: // ST1
case 0x23:{// ST2
int addr = opcode >> 4;
if ( addr )
addr++;
pc++;
FLUSH_TIME();
WRITE_VDP( addr, data );
CACHE_TIME();
goto loop;
}
case 0xEA: // NOP
goto loop;
case 0x54: // CSL
dprintf( "CSL not supported\n" );
illegal_encountered = true;
goto loop;
case 0xD4: // CSH
goto loop;
case 0xF4: { // SET
//int operand = GET_MSB();
dprintf( "SET not handled\n" );
//switch ( data )
//{
//}
illegal_encountered = true;
goto loop;
}
// Block transfer
{
int in_alt;
int in_inc;
int out_alt;
int out_inc;
case 0xE3: // TIA
in_alt = 0;
goto bxfer_alt;
case 0xF3: // TAI
in_alt = 1;
bxfer_alt:
in_inc = in_alt ^ 1;
out_alt = in_inc;
out_inc = in_alt;
goto bxfer;
case 0xD3: // TIN
in_inc = 1;
out_inc = 0;
goto bxfer_no_alt;
case 0xC3: // TDD
in_inc = -1;
out_inc = -1;
goto bxfer_no_alt;
case 0x73: // TII
in_inc = 1;
out_inc = 1;
bxfer_no_alt:
in_alt = 0;
out_alt = 0;
bxfer:
int in = GET_LE16( instr + 0 );
int out = GET_LE16( instr + 2 );
int count = GET_LE16( instr + 4 );
if ( !count )
count = 0x10000;
pc += 6;
WRITE_STACK( SP( -1 ), y );
WRITE_STACK( SP( -2 ), a );
WRITE_STACK( SP( -3 ), x );
FLUSH_TIME();
do
{
// TODO: reads from $0800-$1400 in I/O page should do I/O
int t = READ_MEM( in );
in = WORD( in + in_inc );
s.time += 6;
if ( in_alt )
in_inc = -in_inc;
WRITE_MEM( out, t );
out = WORD( out + out_inc );
if ( out_alt )
out_inc = -out_inc;
}
while ( --count );
CACHE_TIME();
goto loop;
}
// Illegal
default:
check( (unsigned) opcode <= 0xFF );
dprintf( "Illegal opcode $%02X at $%04X\n", (int) opcode, (int) pc - 1 );
illegal_encountered = true;
goto loop;
}
assert( false ); // catch missing 'goto loop' or accidental 'break'
int result_;
handle_brk:
pc++;
result_ = 6;
interrupt:
{
s_time += 7;
// Save PC and read vector
WRITE_STACK( SP( -1 ), pc >> 8 );
WRITE_STACK( SP( -2 ), pc );
pc = GET_LE16( &READ_CODE( 0xFFF0 ) + result_ );
// Save flags
int temp;
GET_FLAGS( temp );
if ( result_ == 6 )
temp |= b10; // BRK sets B bit
sp = SP( -3 );
WRITE_STACK( sp, temp );
// Update I flag in externally-visible flags
flags &= ~d08;
CPU.r.flags = (flags |= i04);
// Update time
int delta = s.base - CPU.end_time_;
if ( delta >= 0 )
goto loop;
s_time += delta;
s.base = CPU.end_time_;
goto loop;
}
idle_done:
s_time = 0;
out_of_time:
pc--;
// Optional action that triggers interrupt or changes irq/end time
#ifdef CPU_DONE
{
CPU_DONE( result_ );
if ( result_ >= 0 )
goto interrupt;
if ( s_time < 0 )
goto loop;
}
#endif
// Flush cached state
CPU.r.pc = pc;
CPU.r.sp = GET_SP();
CPU.r.a = a;
CPU.r.x = x;
CPU.r.y = y;
int temp;
GET_FLAGS( temp );
CPU.r.flags = temp;
CPU.cpu_state_.base = s.base;
CPU.cpu_state_.time = s_time;
CPU.cpu_state = &CPU.cpu_state_;
}