//---------------------------------------------------------------------------
void UpdateCentronicsBusyBit()
{
if ((stick[N_JOY_PARALLEL_1] & BIT_4)==0){
if (ParallelPort.IsOpen()){
if (psg_reg[PSGR_MIXER] & BIT_7){ // Output
// If there are bytes being sent then input is high
mfp_gpip_set_bit(MFP_GPIP_CENTRONICS_BIT,ParallelPort.AreBytesToOutput());
}else{ // Input
// If there are bytes being received then input is high
mfp_gpip_set_bit(MFP_GPIP_CENTRONICS_BIT,ParallelPort.AreBytesToRead());
}
}else{
mfp_gpip_set_bit(MFP_GPIP_CENTRONICS_BIT,true); // Always busy if port closed
}
}
}
/*---------------------------------------------------------------------------*/
void dma_sound_set_control(BYTE io_src_b)
{
if ((dma_sound_control & BIT_0) && (io_src_b & BIT_0)==0){ //Stopping
dma_sound_start=next_dma_sound_start;
dma_sound_end=next_dma_sound_end;
dma_sound_fetch_address=dma_sound_start;
}else if ((dma_sound_control & BIT_0)==0 && (io_src_b & BIT_0)){ //Start playing
dma_sound_start=next_dma_sound_start;
dma_sound_end=next_dma_sound_end;
dma_sound_fetch_address=dma_sound_start;
if (dma_sound_on_this_screen==0){
// Pad buffer with last byte from VBL to current position
bool Mono=bool(dma_sound_mode & BIT_7);
int freq_idx=0;
if (shifter_freq_at_start_of_vbl==60) freq_idx=1;
if (shifter_freq_at_start_of_vbl==MONO_HZ) freq_idx=2;
WORD w1,w2;
dma_sound_get_last_sample(&w1,&w2);
for (int y=-scanlines_above_screen[freq_idx];y<scan_y;y++){
if (Mono){ //play half as many words
dma_sound_samples_countdown+=dma_sound_freq*scanline_time_in_cpu_cycles_at_start_of_vbl/2;
}else{ //stereo, 1 word per sample
dma_sound_samples_countdown+=dma_sound_freq*scanline_time_in_cpu_cycles_at_start_of_vbl;
}
int loop=int(Mono ? 2:1);
while (dma_sound_samples_countdown>=0){
for (int i=0;i<loop;i++){
dma_sound_output_countdown+=sound_freq;
while (dma_sound_output_countdown>=0){
if (dma_sound_channel_buf_last_write_t>=DMA_SOUND_BUFFER_LENGTH) break;
dma_sound_channel_buf[dma_sound_channel_buf_last_write_t++]=w1;
dma_sound_channel_buf[dma_sound_channel_buf_last_write_t++]=w2;
dma_sound_output_countdown-=dma_sound_freq;
}
}
dma_sound_samples_countdown-=n_cpu_cycles_per_second;
}
}
dma_sound_on_this_screen=1;
}
}
log_to(LOGSECTION_SOUND,EasyStr("SOUND: ")+HEXSl(old_pc,6)+" - DMA sound control set to "+(io_src_b & 3)+" from "+(dma_sound_control & 3));
dma_sound_control=io_src_b;
if (tos_version>=0x106) mfp_gpip_set_bit(MFP_GPIP_MONO_BIT,bool(COLOUR_MONITOR)^bool(dma_sound_control & BIT_0));
}
//---------------------------------------------------------------------------
// MIDI Port
//---------------------------------------------------------------------------
void agenda_midi_replace(int)
{
if (MIDIPort.AreBytesToCome()){
MIDIPort.NextByte();
if (ACIA_MIDI.rx_not_read){
// discard data and set overrun
log_to_section(LOGSECTION_MIDI,"MIDI: Overrun on ACIA! Byte lost!");
if (ACIA_MIDI.overrun!=ACIA_OVERRUN_YES) ACIA_MIDI.overrun=ACIA_OVERRUN_COMING;
}else{
ACIA_MIDI.data=MIDIPort.ReadByte();
ACIA_MIDI.rx_not_read=true;
}
log_to_section(LOGSECTION_MIDI,EasyStr("MIDI: Fire ACIA interrupt"));
if (ACIA_MIDI.rx_irq_enabled) ACIA_MIDI.irq=true;
mfp_gpip_set_bit(MFP_GPIP_ACIA_BIT,!(ACIA_IKBD.irq || ACIA_MIDI.irq));
if (MIDIPort.AreBytesToCome()) agenda_add(agenda_midi_replace,ACIAClockToHBLS(ACIA_MIDI.clock_divide,true),0);
}
}
//---------------------------------------------------------------------------
BYTE ASMCALL io_read_b(MEM_ADDRESS addr)
{
/*
Allowed addresses
000000 - 3FFFFF RAM
D00000 - D7FFFF
E00000 - E3FFFF TOS
E40000 - EBFFFF
FA0000 - FBFFFF Cart
FE0000 - FE1FFF
FF8000 - FF800F MMU
FF8200 - FF820F SHIFTER
FF8240 - FF827F pallette, res
FF8608 - FF860F FDC
FF8800 - FF88FF sound chip
FF8900 - FF893F DMA sound, microwire
FF8A00 - FF8A3F blitter
FF9000 - FF9001
FF9201, FF9202, FF9203 paddles
FF9211, FF9213, FF9215, FF9217 paddles
FFFA01, odd addresses up to FFFA3F MFP
FFFC00 - FFFDFF ACIA, realtime clock
Word differences:
FF8604 - FF860F FDC
FF9200, FF9202 paddles
FF9210, FF9212, FF9214, FF9216 paddles
FF9220, FF9222 paddles
FFFA00 - FFFA3F MFP
*/
DEBUG_CHECK_READ_IO_B(addr);
#ifdef ONEGAME
if (addr>=OG_TEXT_ADDRESS && addr<OG_TEXT_ADDRESS+OG_TEXT_LEN){
return BYTE(OG_TextMem[addr-OG_TEXT_ADDRESS]);
}
#endif
switch (addr & 0xffff00){ //fffe00
case 0xfffc00: //----------------------------------- ACIAs
{
// Only cause bus jam once per word
DEBUG_ONLY( if (mode==STEM_MODE_CPU) )
{
if (io_word_access==0 || (addr & 1)==0){
// if (passed VBL or HBL point){
// BUS_JAM_TIME(4);
// }else{
// Jorge Cwik:
// Access to the ACIA is synchronized to the E signal. Which is a clock with
// one tenth the frequency of the main CPU clock (800 Khz). So the timing
// should depend on the phase relationship between both clocks.
int rel_cycle=ABSOLUTE_CPU_TIME-shifter_cycle_base;
rel_cycle=8000000-rel_cycle;
rel_cycle%=10;
BUS_JAM_TIME(rel_cycle+6);
// BUS_JAM_TIME(8);
}
}
switch (addr){
/******************** Keyboard ACIA ************************/
case 0xfffc00: //status
{
BYTE x=0;
if (ACIA_IKBD.rx_not_read || ACIA_IKBD.overrun==ACIA_OVERRUN_YES) x|=BIT_0; //full bit
if (ACIA_IKBD.tx_flag==0) x|=BIT_1; //empty bit
// if (acia[ACIA_IKBD].rx_not_read && acia[ACIA_IKBD].rx_irq_enabled) x|=BIT_7; //irq bit
if (ACIA_IKBD.irq) x|=BIT_7; //irq bit
if (ACIA_IKBD.overrun==ACIA_OVERRUN_YES) x|=BIT_5; //overrun
return x;
}
case 0xfffc02: //data
{
DEBUG_ONLY( if (mode!=STEM_MODE_CPU) return ACIA_IKBD.data; )
// if (acia[ACIA_IKBD].rx_not_read) keyboard_buffer_length--;
ACIA_IKBD.rx_not_read=0;
LOG_ONLY( bool old_irq=ACIA_IKBD.irq; )
if (ACIA_IKBD.overrun==ACIA_OVERRUN_COMING){
ACIA_IKBD.overrun=ACIA_OVERRUN_YES;
if (ACIA_IKBD.rx_irq_enabled) ACIA_IKBD.irq=true;
LOG_ONLY( log_to_section(LOGSECTION_IKBD,EasyStr("IKBD: ")+HEXSl(old_pc,6)+
" - OVERRUN! Read data ($"+HEXSl(ACIA_IKBD.data,2)+
"), changing ACIA IRQ bit from "+old_irq+" to "+ACIA_IKBD.irq); )
}else{
ACIA_IKBD.overrun=ACIA_OVERRUN_NO;
// IRQ should be off for receive, but could be set for tx empty interrupt
ACIA_IKBD.irq=(ACIA_IKBD.tx_irq_enabled && ACIA_IKBD.tx_flag==0);
LOG_ONLY( if (ACIA_IKBD.irq!=old_irq) log_to_section(LOGSECTION_IKBD,Str("IKBD: ")+
HEXSl(old_pc,6)+" - Read data ($"+HEXSl(ACIA_IKBD.data,2)+
"), changing ACIA IRQ bit from "+old_irq+" to "+ACIA_IKBD.irq); )
}
mfp_gpip_set_bit(MFP_GPIP_ACIA_BIT,!(ACIA_IKBD.irq || ACIA_MIDI.irq));
return ACIA_IKBD.data;
}
