libspectrum_byte
readbyte( libspectrum_word address )
{
libspectrum_word bank;
memory_page *mapping;
bank = address >> MEMORY_PAGE_SIZE_LOGARITHM;
mapping = &memory_map_read[ bank ];
if( debugger_mode != DEBUGGER_MODE_INACTIVE )
debugger_check( DEBUGGER_BREAKPOINT_TYPE_READ, address );
if( mapping->contended ) tstates += ula_contention[ tstates ];
tstates += 3;
if( opus_active && address >= 0x2800 && address < 0x3800 )
return opus_read( address );
if( spectranet_paged ) {
if( spectranet_w5100_paged_a && address >= 0x1000 && address < 0x2000 )
return spectranet_w5100_read( mapping, address );
if( spectranet_w5100_paged_b && address >= 0x2000 && address < 0x3000 )
return spectranet_w5100_read( mapping, address );
}
return mapping->page[ address & MEMORY_PAGE_SIZE_MASK ];
}
void
writebyte( libspectrum_word address, libspectrum_byte b )
{
libspectrum_word bank;
memory_page *mapping;
bank = address >> 13;
mapping = &memory_map_write[ bank ];
if( debugger_mode != DEBUGGER_MODE_INACTIVE )
debugger_check( DEBUGGER_BREAKPOINT_TYPE_WRITE, address );
if( mapping->contended ) tstates += ula_contention[ tstates ];
tstates += 3;
writebyte_internal( address, b );
}
libspectrum_byte
readbyte( libspectrum_word address )
{
libspectrum_word bank;
memory_page *mapping;
bank = address >> 13;
mapping = &memory_map_read[ bank ];
if( debugger_mode != DEBUGGER_MODE_INACTIVE )
debugger_check( DEBUGGER_BREAKPOINT_TYPE_READ, address );
if( mapping->contended ) tstates += ula_contention[ tstates ];
tstates += 3;
if( opus_active && address >= 0x2800 && address < 0x3800 )
return opus_read( address );
return mapping->page[ address & 0x1fff ];
}
/* Execute Z80 opcodes until the next event */
void
z80_do_opcodes( void )
{
#ifdef HAVE_ENOUGH_MEMORY
libspectrum_byte opcode = 0x00;
#endif
int even_m1 =
machine_current->capabilities & LIBSPECTRUM_MACHINE_CAPABILITY_EVEN_M1;
#ifdef __GNUC__
#undef SETUP_CHECK
#define SETUP_CHECK( label, condition ) \
if( condition ) { cgoto[ next ] = &&label; next = pos_##label + 1; } \
check++;
#undef SETUP_NEXT
#define SETUP_NEXT( label ) \
if( next != check ) { cgoto[ next ] = &&label; } \
next = check;
void *cgoto[ numchecks ]; size_t next = 0; size_t check = 0;
#include "z80_checks.h"
#endif /* #ifdef __GNUC__ */
while( tstates < event_next_event ) {
/* Profiler */
CHECK( profile, profile_active )
profile_map( PC );
END_CHECK
/* If we're due an end of frame from RZX playback, generate one */
CHECK( rzx, rzx_playback )
if( R + rzx_instructions_offset >= rzx_instruction_count ) {
event_add( tstates, spectrum_frame_event );
break; /* And break out of the execution loop to let
the interrupt happen */
}
END_CHECK
/* Check if the debugger should become active at this point */
CHECK( debugger, debugger_mode != DEBUGGER_MODE_INACTIVE )
if( !z80.halted && debugger_check( DEBUGGER_BREAKPOINT_TYPE_EXECUTE, PC ) )
debugger_trap();
END_CHECK
CHECK( beta, beta_available )
#define NOT_128_TYPE_OR_IS_48_TYPE ( !( machine_current->capabilities & \
LIBSPECTRUM_MACHINE_CAPABILITY_128_MEMORY ) || \
machine_current->ram.current_rom )
if( beta_active ) {
if( NOT_128_TYPE_OR_IS_48_TYPE && PC >= 16384 ) {
beta_unpage();
}
} else if( ( PC & beta_pc_mask ) == beta_pc_value &&
NOT_128_TYPE_OR_IS_48_TYPE ) {
beta_page();
}
END_CHECK
CHECK( plusd, plusd_available )
if( PC == 0x0008 || PC == 0x003a || PC == 0x0066 || PC == 0x028e ) {
plusd_page();
}
END_CHECK
CHECK( didaktik80, didaktik80_available )
if( PC == 0x0000 || PC == 0x0008 ) {
didaktik80_page();
} else if( PC == 0x1700 ) {
didaktik80_unpage();
}
END_CHECK
CHECK( disciple, disciple_available )
if( PC == 0x0001 || PC == 0x0008 || PC == 0x0066 || PC == 0x028e ) {
disciple_page();
}
END_CHECK
CHECK( usource, usource_available )
if( PC == 0x2bae ) {
usource_toggle();
}
END_CHECK
CHECK( if1p, if1_available )
if( PC == 0x0008 || PC == 0x1708 ) {
if1_page();
}
END_CHECK
CHECK( divide_early, settings_current.divide_enabled )
if( ( PC & 0xff00 ) == 0x3d00 ) {
divide_set_automap( 1 );
}
END_CHECK
CHECK( spectranet_page, spectranet_available && !settings_current.spectranet_disable )
if( PC == 0x0008 || ((PC & 0xfff8) == 0x3ff8) )
spectranet_page( 0 );
if( PC == spectranet_programmable_trap &&
spectranet_programmable_trap_active )
event_add( 0, z80_nmi_event );
END_CHECK
opcode_delay:
contend_read( PC, 4 );
/* Check to see if M1 cycles happen on even tstates */
CHECK( evenm1, even_m1 )
if( tstates & 1 ) {
if( ++tstates == event_next_event ) {
break;
}
}
END_CHECK
run_opcode:
/* Do the instruction fetch; readbyte_internal used here to avoid
triggering read breakpoints */
opcode = readbyte_internal( PC );
CHECK( if1u, if1_available )
if( PC == 0x0700 ) {
if1_unpage();
}
END_CHECK
CHECK( divide_late, settings_current.divide_enabled )
if( ( PC & 0xfff8 ) == 0x1ff8 ) {
divide_set_automap( 0 );
} else if( (PC == 0x0000) || (PC == 0x0008) || (PC == 0x0038)
|| (PC == 0x0066) || (PC == 0x04c6) || (PC == 0x0562) ) {
divide_set_automap( 1 );
}
END_CHECK
CHECK( opus, opus_available )
if( opus_active ) {
if( PC == 0x1748 ) {
opus_unpage();
}
} else if( PC == 0x0008 || PC == 0x0048 || PC == 0x1708 ) {
opus_page();
}
END_CHECK
CHECK( spectranet_unpage, spectranet_available )
if( PC == 0x007c )
spectranet_unpage();
END_CHECK
CHECK( z80_halted, z80.halted )
/* Opcode read from memory is ignored and PC is left unchanged */
R++;
continue;
END_CHECK
CHECK( z80_iff2_read, z80.iff2_read )
z80.iff2_read = 0;
/* Execute *one* instruction before reevaluating the checks */
event_add( tstates, z80_nmos_iff2_event );
END_CHECK
CHECK( didaktik80snap, didaktik80_snap )
if( PC == 0x0066 && !didaktik80_active ) {
opcode = 0xc7; /* RST 00 */
didaktik80_snap = 0; /* FIXME: this should be a time-based reset */
}
END_CHECK
CHECK( svg_capture, svg_capture_active )
svg_capture();
END_CHECK
end_opcode:
PC++; R++;
switch(opcode) {
#include "z80/opcodes_base.c"
}
}
}
