mirrors
/
Bochs
mirror of https://github.com/bochs-emu/Bochs
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
Bochs/bochs/iodev/pit82c54.cc

980 lines
30 KiB
C++
Raw Permalink Blame History

/////////////////////////////////////////////////////////////////////////
// $Id$
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001-2021 The Bochs Project
//
// This library 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 of the License, or (at your option) any later version.
//
// This library 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 library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
/*
* Emulator of an Intel 8254/82C54 Programmable Interval Timer.
* Greg Alexander <yakovlev@usa.com>
*
*
* Things I am unclear on (greg):
* 1.)What happens if both the status and count registers are latched,
* but the first of the two count registers has already been read?
* I.E.:
* latch count 0 (16-bit)
* Read count 0 (read LSByte)
* READ_BACK status of count 0
* Read count 0 - do you get MSByte or status?
* This will be flagged as an error.
* 2.)What happens when we latch the output in the middle of a 2-part
* unlatched read?
* 3.)I assumed that programming a counter removes a latched status.
* 4.)I implemented the 8254 description of mode 0, not the 82C54 one.
* 5.)clock() calls represent a rising clock edge followed by a falling
* clock edge.
* 6.)What happens when we trigger mode 1 in the middle of a 2-part
* write?
*/
// Define BX_PLUGGABLE in files that can be compiled into plugins. For
// platforms that require a special tag on exported symbols, BX_PLUGGABLE
// is used to know when we are exporting symbols and when we are importing.
#define BX_PLUGGABLE
#include "iodev.h"
#include "pit82c54.h"
#define LOG_THIS this->
void pit_82C54::print_counter(counter_type &thisctr)
{
#if BX_DEBUGGER
dbg_printf("count: %d\n", thisctr.count);
dbg_printf("count_binary: 0x%04x\n", thisctr.count_binary);
dbg_printf("counter GATE: %x\n", thisctr.GATE);
dbg_printf("counter OUT: %x\n", thisctr.OUTpin);
dbg_printf("next_change_time: %d\n", thisctr.next_change_time);
#endif
}
void pit_82C54::print_cnum(Bit8u cnum)
{
if (cnum>MAX_COUNTER) {
BX_ERROR(("Bad counter index to print_cnum"));
} else {
print_counter(counter[cnum]);
}
}
void pit_82C54::latch_counter(counter_type &thisctr)
{
if (thisctr.count_LSB_latched || thisctr.count_MSB_latched) {
//Do nothing because previous latch has not been read.;
} else {
switch(thisctr.read_state) {
case MSByte:
thisctr.outlatch=thisctr.count & 0xFFFF;
thisctr.count_MSB_latched=1;
break;
case LSByte:
thisctr.outlatch=thisctr.count & 0xFFFF;
thisctr.count_LSB_latched=1;
break;
case LSByte_multiple:
thisctr.outlatch=thisctr.count & 0xFFFF;
thisctr.count_LSB_latched=1;
thisctr.count_MSB_latched=1;
break;
case MSByte_multiple:
if (!(seen_problems & UNL_2P_READ)) {
// seen_problems|=UNL_2P_READ;
BX_ERROR(("Unknown behavior when latching during 2-part read."));
BX_ERROR((" This message will not be repeated."));
}
//I guess latching and resetting to LSB first makes sense;
BX_DEBUG(("Setting read_state to LSB_mult"));
thisctr.read_state=LSByte_multiple;
thisctr.outlatch=thisctr.count & 0xFFFF;
thisctr.count_LSB_latched=1;
thisctr.count_MSB_latched=1;
break;
default:
BX_ERROR(("Unknown read mode found during latch command."));
break;
}
}
}
void pit_82C54::set_OUT(counter_type &thisctr, bool data)
{
if (thisctr.OUTpin != data) {
thisctr.OUTpin = data;
if (thisctr.out_handler != NULL) {
thisctr.out_handler(data);
}
}
}
void BX_CPP_AttrRegparmN(2) pit_82C54::set_count(counter_type &thisctr, Bit32u data)
{
thisctr.count=data & 0xFFFF;
set_binary_to_count(thisctr);
}
void BX_CPP_AttrRegparmN(1) pit_82C54::set_count_to_binary(counter_type &thisctr)
{
if (thisctr.bcd_mode) {
thisctr.count=
(((thisctr.count_binary/1)%10)<<0) |
(((thisctr.count_binary/10)%10)<<4) |
(((thisctr.count_binary/100)%10)<<8) |
(((thisctr.count_binary/1000)%10)<<12);
} else {
thisctr.count=thisctr.count_binary;
}
}
void BX_CPP_AttrRegparmN(1) pit_82C54::set_binary_to_count(counter_type &thisctr)
{
if (thisctr.bcd_mode) {
thisctr.count_binary=
(1*((thisctr.count>>0)&0xF)) +
(10*((thisctr.count>>4)&0xF)) +
(100*((thisctr.count>>8)&0xF)) +
(1000*((thisctr.count>>12)&0xF));
} else {
thisctr.count_binary=thisctr.count;
}
}
void BX_CPP_AttrRegparmN(1) pit_82C54::decrement (counter_type &thisctr)
{
if (!thisctr.count) {
if (thisctr.bcd_mode) {
thisctr.count=0x9999;
thisctr.count_binary=9999;
} else {
thisctr.count=0xFFFF;
thisctr.count_binary=0xFFFF;
}
} else {
thisctr.count_binary--;
set_count_to_binary(thisctr);
}
}
void pit_82C54::init(void)
{
put("pit82c54", "PIT81");
for(int i=0;i<3;i++) {
BX_DEBUG(("Setting read_state to LSB"));
counter[i].read_state=LSByte;
counter[i].write_state=LSByte;
counter[i].GATE=1;
counter[i].OUTpin=1;
counter[i].triggerGATE=0;
counter[i].mode=4;
counter[i].first_pass=0;
counter[i].bcd_mode=0;
counter[i].count=0;
counter[i].count_binary=0;
counter[i].state_bit_1=0;
counter[i].state_bit_2=0;
counter[i].null_count=0;
counter[i].rw_mode=1;
counter[i].count_written=1;
counter[i].count_LSB_latched=0;
counter[i].count_MSB_latched=0;
counter[i].status_latched=0;
counter[i].next_change_time=0;
counter[i].out_handler=NULL;
}
seen_problems=0;
}
pit_82C54::pit_82C54(void)
{
init();
}
void pit_82C54::reset(unsigned type) {}
void pit_82C54::register_state(bx_param_c *parent)
{
char name[4];
for (unsigned i=0; i<3; i++) {
sprintf(name, "%u", i);
bx_list_c *tim = new bx_list_c(parent, name);
BXRS_PARAM_BOOL(tim, GATE, counter[i].GATE);
BXRS_PARAM_BOOL(tim, OUTpin, counter[i].OUTpin);
new bx_shadow_num_c(tim, "count", &counter[i].count);
new bx_shadow_num_c(tim, "outlatch", &counter[i].outlatch);
new bx_shadow_num_c(tim, "inlatch", &counter[i].inlatch);
new bx_shadow_num_c(tim, "status_latch", &counter[i].status_latch);
new bx_shadow_num_c(tim, "rw_mode", &counter[i].rw_mode);
new bx_shadow_num_c(tim, "mode", &counter[i].mode);
BXRS_PARAM_BOOL(tim, bcd_mode, counter[i].bcd_mode);
BXRS_PARAM_BOOL(tim, null_count, counter[i].null_count);
BXRS_PARAM_BOOL(tim, count_LSB_latched, counter[i].count_LSB_latched);
BXRS_PARAM_BOOL(tim, count_MSB_latched, counter[i].count_MSB_latched);
BXRS_PARAM_BOOL(tim, status_latched, counter[i].status_latched);
new bx_shadow_num_c(tim, "count_binary", &counter[i].count_binary);
BXRS_PARAM_BOOL(tim, triggerGATE, counter[i].triggerGATE);
new bx_shadow_num_c(tim, "write_state", (Bit8u*)&counter[i].write_state);
new bx_shadow_num_c(tim, "read_state", (Bit8u*)&counter[i].read_state);
BXRS_PARAM_BOOL(tim, count_written, counter[i].count_written);
BXRS_PARAM_BOOL(tim, first_pass, counter[i].first_pass);
BXRS_PARAM_BOOL(tim, state_bit_1, counter[i].state_bit_1);
BXRS_PARAM_BOOL(tim, state_bit_2, counter[i].state_bit_2);
new bx_shadow_num_c(tim, "next_change_time", &counter[i].next_change_time);
}
}
void BX_CPP_AttrRegparmN(2) pit_82C54::decrement_multiple(counter_type &thisctr, Bit32u cycles)
{
while(cycles>0) {
if (cycles<=thisctr.count_binary) {
thisctr.count_binary-=cycles;
cycles-=cycles;
set_count_to_binary(thisctr);
} else {
cycles-=(thisctr.count_binary+1);
thisctr.count_binary-=thisctr.count_binary;
set_count_to_binary(thisctr);
decrement(thisctr);
}
}
}
void pit_82C54::clock_multiple(Bit8u cnum, Bit32u cycles)
{
if (cnum>MAX_COUNTER) {
BX_ERROR(("Counter number too high in clock"));
} else {
counter_type &thisctr = counter[cnum];
while(cycles>0) {
if (thisctr.next_change_time==0) {
if (thisctr.count_written) {
switch(thisctr.mode) {
case 0:
if (thisctr.GATE && (thisctr.write_state!=MSByte_multiple)) {
decrement_multiple(thisctr, cycles);
}
break;
case 1:
decrement_multiple(thisctr, cycles);
break;
case 2:
if (!thisctr.first_pass && thisctr.GATE) {
decrement_multiple(thisctr, cycles);
}
break;
case 3:
if (!thisctr.first_pass && thisctr.GATE) {
decrement_multiple(thisctr, 2*cycles);
}
break;
case 4:
if (thisctr.GATE) {
decrement_multiple(thisctr, cycles);
}
break;
case 5:
decrement_multiple(thisctr, cycles);
break;
default:
break;
}
}
cycles-=cycles;
} else {
switch(thisctr.mode) {
case 0:
case 1:
case 2:
case 4:
case 5:
if (thisctr.next_change_time > cycles) {
decrement_multiple(thisctr,cycles);
thisctr.next_change_time-=cycles;
cycles-=cycles;
} else {
decrement_multiple(thisctr,(thisctr.next_change_time-1));
cycles-=thisctr.next_change_time;
clock(cnum);
}
break;
case 3:
if (thisctr.next_change_time > cycles) {
decrement_multiple(thisctr,cycles*2);
thisctr.next_change_time-=cycles;
cycles-=cycles;
} else {
decrement_multiple(thisctr,(thisctr.next_change_time-1)*2);
cycles-=thisctr.next_change_time;
clock(cnum);
}
break;
default:
cycles-=cycles;
break;
}
}
}
}
}
void BX_CPP_AttrRegparmN(1) pit_82C54::clock(Bit8u cnum)
{
if (cnum>MAX_COUNTER) {
BX_ERROR(("Counter number too high in clock"));
} else {
counter_type &thisctr = counter[cnum];
switch(thisctr.mode) {
case 0:
if (thisctr.count_written) {
if (thisctr.null_count) {
set_count(thisctr, thisctr.inlatch);
if (thisctr.GATE) {
if (thisctr.count_binary==0) {
thisctr.next_change_time=1;
} else {
thisctr.next_change_time=thisctr.count_binary & 0xFFFF;
}
} else {
thisctr.next_change_time=0;
}
thisctr.null_count=0;
} else {
if (thisctr.GATE && (thisctr.write_state!=MSByte_multiple)) {
decrement(thisctr);
if (!thisctr.OUTpin) {
thisctr.next_change_time=thisctr.count_binary & 0xFFFF;
if (!thisctr.count) {
set_OUT(thisctr,1);
}
} else {
thisctr.next_change_time=0;
}
} else {
thisctr.next_change_time=0; //if the clock isn't moving.
}
}
} else {
thisctr.next_change_time=0; //default to 0.
}
thisctr.triggerGATE=0;
break;
case 1:
if (thisctr.count_written) {
if (thisctr.triggerGATE) {
set_count(thisctr, thisctr.inlatch);
if (thisctr.count_binary==0) {
thisctr.next_change_time=1;
} else {
thisctr.next_change_time=thisctr.count_binary & 0xFFFF;
}
thisctr.null_count=0;
set_OUT(thisctr,0);
if (thisctr.write_state==MSByte_multiple) {
BX_ERROR(("Undefined behavior when loading a half loaded count."));
}
} else {
decrement(thisctr);
if (!thisctr.OUTpin) {
if (thisctr.count_binary==0) {
thisctr.next_change_time=1;
} else {
thisctr.next_change_time=thisctr.count_binary & 0xFFFF;
}
if (thisctr.count==0) {
set_OUT(thisctr,1);
}
} else {
thisctr.next_change_time=0;
}
}
} else {
thisctr.next_change_time=0; //default to 0.
}
thisctr.triggerGATE=0;
break;
case 2:
if (thisctr.count_written) {
if (thisctr.triggerGATE || thisctr.first_pass) {
set_count(thisctr, thisctr.inlatch);
thisctr.next_change_time=(thisctr.count_binary-1) & 0xFFFF;
thisctr.null_count=0;
if (thisctr.inlatch==1) {
BX_ERROR(("ERROR: count of 1 is invalid in pit mode 2."));
}
if (!thisctr.OUTpin) {
set_OUT(thisctr,1);
}
if (thisctr.write_state==MSByte_multiple) {
BX_ERROR(("Undefined behavior when loading a half loaded count."));
}
thisctr.first_pass=0;
} else {
if (thisctr.GATE) {
decrement(thisctr);
thisctr.next_change_time=(thisctr.count_binary-1) & 0xFFFF;
if (thisctr.count==1) {
thisctr.next_change_time=1;
set_OUT(thisctr,0);
thisctr.first_pass=1;
}
} else {
thisctr.next_change_time=0;
}
}
} else {
thisctr.next_change_time=0;
}
thisctr.triggerGATE=0;
break;
case 3:
if (thisctr.count_written) {
if ((thisctr.triggerGATE || thisctr.first_pass
|| thisctr.state_bit_2) && thisctr.GATE) {
set_count(thisctr, thisctr.inlatch & 0xFFFE);
thisctr.state_bit_1=thisctr.inlatch & 0x1;
if (!thisctr.OUTpin || !thisctr.state_bit_1) {
if (((thisctr.count_binary/2)-1)==0) {
thisctr.next_change_time=1;
} else {
thisctr.next_change_time=((thisctr.count_binary/2)-1) & 0xFFFF;
}
} else {
if ((thisctr.count_binary/2)==0) {
thisctr.next_change_time=1;
} else {
thisctr.next_change_time=(thisctr.count_binary/2) & 0xFFFF;
}
}
thisctr.null_count=0;
if (thisctr.inlatch==1) {
BX_ERROR(("Count of 1 is invalid in pit mode 3."));
}
if (!thisctr.OUTpin) {
set_OUT(thisctr,1);
} else if (thisctr.OUTpin && !thisctr.first_pass) {
set_OUT(thisctr,0);
}
if (thisctr.write_state==MSByte_multiple) {
BX_ERROR(("Undefined behavior when loading a half loaded count."));
}
thisctr.state_bit_2=0;
thisctr.first_pass=0;
} else {
if (thisctr.GATE) {
decrement(thisctr);
decrement(thisctr);
if (!thisctr.OUTpin || !thisctr.state_bit_1) {
thisctr.next_change_time=((thisctr.count_binary/2)-1) & 0xFFFF;
} else {
thisctr.next_change_time=(thisctr.count_binary/2) & 0xFFFF;
}
if (thisctr.count==0) {
thisctr.state_bit_2=1;
thisctr.next_change_time=1;
}
if ((thisctr.count==2) &&
(!thisctr.OUTpin || !thisctr.state_bit_1))
{
thisctr.state_bit_2=1;
thisctr.next_change_time=1;
}
} else {
thisctr.next_change_time=0;
}
}
} else {
thisctr.next_change_time=0;
}
thisctr.triggerGATE=0;
break;
case 4:
if (thisctr.count_written) {
if (!thisctr.OUTpin) {
set_OUT(thisctr,1);
}
if (thisctr.null_count) {
set_count(thisctr, thisctr.inlatch);
if (thisctr.GATE) {
if (thisctr.count_binary==0) {
thisctr.next_change_time=1;
} else {
thisctr.next_change_time=thisctr.count_binary & 0xFFFF;
}
} else {
thisctr.next_change_time=0;
}
thisctr.null_count=0;
if (thisctr.write_state==MSByte_multiple) {
BX_ERROR(("Undefined behavior when loading a half loaded count."));
}
thisctr.first_pass=1;
} else {
if (thisctr.GATE) {
decrement(thisctr);
if (thisctr.first_pass) {
thisctr.next_change_time=thisctr.count_binary & 0xFFFF;
if (!thisctr.count) {
set_OUT(thisctr,0);
thisctr.next_change_time=1;
thisctr.first_pass=0;
}
} else {
thisctr.next_change_time=0;
}
} else {
thisctr.next_change_time=0;
}
}
} else {
thisctr.next_change_time=0;
}
thisctr.triggerGATE=0;
break;
case 5:
if (thisctr.count_written) {
if (!thisctr.OUTpin) {
set_OUT(thisctr,1);
}
if (thisctr.triggerGATE) {
set_count(thisctr, thisctr.inlatch);
if (thisctr.count_binary==0) {
thisctr.next_change_time=1;
} else {
thisctr.next_change_time=thisctr.count_binary & 0xFFFF;
}
thisctr.null_count=0;
if (thisctr.write_state==MSByte_multiple) {
BX_ERROR(("Undefined behavior when loading a half loaded count."));
}
thisctr.first_pass=1;
} else {
decrement(thisctr);
if (thisctr.first_pass) {
thisctr.next_change_time=thisctr.count_binary & 0xFFFF;
if (!thisctr.count) {
set_OUT(thisctr,0);
thisctr.next_change_time=1;
thisctr.first_pass=0;
}
} else {
thisctr.next_change_time=0;
}
}
} else {
thisctr.next_change_time=0;
}
thisctr.triggerGATE=0;
break;
default:
BX_ERROR(("Mode not implemented."));
thisctr.next_change_time=0;
thisctr.triggerGATE=0;
break;
}
}
}
void pit_82C54::clock_all(Bit32u cycles)
{
BX_DEBUG(("clock_all: cycles=%d",cycles));
clock_multiple(0,cycles);
clock_multiple(1,cycles);
clock_multiple(2,cycles);
}
Bit8u pit_82C54::read(Bit8u address)
{
if (address>MAX_ADDRESS) {
BX_ERROR(("Counter address incorrect in data read."));
} else if (address==CONTROL_ADDRESS) {
BX_DEBUG(("PIT Read: Control Word Register."));
//Read from control word register;
/* This might be okay. If so, 0 seems the most logical
* return value from looking at the docs.
*/
BX_ERROR(("Read from control word register not defined."));
return 0;
} else {
//Read from a counter;
BX_DEBUG(("PIT Read: Counter %d.",address));
counter_type &thisctr=counter[address];
if (thisctr.status_latched) {
//Latched Status Read;
if (thisctr.count_MSB_latched &&
(thisctr.read_state==MSByte_multiple)) {
BX_ERROR(("Undefined output when status latched and count half read."));
} else {
thisctr.status_latched=0;
return thisctr.status_latch;
}
} else {
//Latched Count Read;
if (thisctr.count_LSB_latched) {
//Read Least Significant Byte;
if (thisctr.read_state==LSByte_multiple) {
BX_DEBUG(("Setting read_state to MSB_mult"));
thisctr.read_state=MSByte_multiple;
}
thisctr.count_LSB_latched=0;
return (thisctr.outlatch & 0xFF);
} else if (thisctr.count_MSB_latched) {
//Read Most Significant Byte;
if (thisctr.read_state==MSByte_multiple) {
BX_DEBUG(("Setting read_state to LSB_mult"));
thisctr.read_state=LSByte_multiple;
}
thisctr.count_MSB_latched=0;
return ((thisctr.outlatch>>8) & 0xFF);
} else {
//Unlatched Count Read;
if (!(thisctr.read_state & 0x1)) {
//Read Least Significant Byte;
if (thisctr.read_state==LSByte_multiple) {
thisctr.read_state=MSByte_multiple;
BX_DEBUG(("Setting read_state to MSB_mult"));
}
return (thisctr.count & 0xFF);
} else {
//Read Most Significant Byte;
if (thisctr.read_state==MSByte_multiple) {
BX_DEBUG(("Setting read_state to LSB_mult"));
thisctr.read_state=LSByte_multiple;
}
return ((thisctr.count>>8) & 0xFF);
}
}
}
}
//Should only get here on errors;
return 0;
}
void pit_82C54::write(Bit8u address, Bit8u data)
{
if (address>MAX_ADDRESS) {
BX_ERROR(("Counter address incorrect in data write."));
} else if (address==CONTROL_ADDRESS) {
Bit8u SC, RW, M, BCD;
controlword=data;
BX_DEBUG(("Control Word Write."));
SC = (controlword>>6) & 0x3;
RW = (controlword>>4) & 0x3;
M = (controlword>>1) & 0x7;
BCD = controlword & 0x1;
if (SC == 3) {
//READ_BACK command;
int i;
BX_DEBUG(("READ_BACK command."));
for(i=0;i<=MAX_COUNTER;i++) {
if ((M>>i) & 0x1) {
//If we are using this counter;
counter_type &thisctr=counter[i];
if (!((controlword>>5) & 1)) {
//Latch Count;
latch_counter(thisctr);
}
if (!((controlword>>4) & 1)) {
//Latch Status;
if (thisctr.status_latched) {
//Do nothing because latched status has not been read.;
} else {
thisctr.status_latch=
((thisctr.OUTpin & 0x1) << 7) |
((thisctr.null_count & 0x1) << 6) |
((thisctr.rw_mode & 0x3) << 4) |
((thisctr.mode & 0x7) << 1) |
(thisctr.bcd_mode&0x1);
thisctr.status_latched=1;
}
}
}
}
} else {
counter_type &thisctr = counter[SC];
if (!RW) {
//Counter Latch command;
BX_DEBUG(("Counter Latch command. SC=%d",SC));
latch_counter(thisctr);
} else {
//Counter Program Command;
BX_DEBUG(("Counter Program command. SC=%d, RW=%d, M=%d, BCD=%d",SC,RW,M,BCD));
thisctr.null_count=1;
thisctr.count_LSB_latched=0;
thisctr.count_MSB_latched=0;
thisctr.status_latched=0;
thisctr.inlatch=0;
thisctr.count_written=0;
thisctr.first_pass=1;
thisctr.rw_mode=RW;
thisctr.bcd_mode=(BCD > 0);
thisctr.mode=M;
switch(RW) {
case 0x1:
BX_DEBUG(("Setting read_state to LSB"));
thisctr.read_state=LSByte;
thisctr.write_state=LSByte;
break;
case 0x2:
BX_DEBUG(("Setting read_state to MSB"));
thisctr.read_state=MSByte;
thisctr.write_state=MSByte;
break;
case 0x3:
BX_DEBUG(("Setting read_state to LSB_mult"));
thisctr.read_state=LSByte_multiple;
thisctr.write_state=LSByte_multiple;
break;
default:
BX_ERROR(("RW field invalid in control word write."));
break;
}
//All modes except mode 0 have initial output of 1.;
if (M) {
set_OUT(thisctr, 1);
} else {
set_OUT(thisctr, 0);
}
thisctr.next_change_time=0;
}
}
} else {
//Write to counter initial value.
counter_type &thisctr = counter[address];
BX_DEBUG(("Write Initial Count: counter=%d, count=%d",address,data));
switch(thisctr.write_state) {
case LSByte_multiple:
thisctr.inlatch = data;
thisctr.write_state = MSByte_multiple;
break;
case LSByte:
thisctr.inlatch = data;
thisctr.count_written = 1;
break;
case MSByte_multiple:
thisctr.write_state = LSByte_multiple;
thisctr.inlatch |= (data << 8);
thisctr.count_written = 1;
break;
case MSByte:
thisctr.inlatch = (data << 8);
thisctr.count_written = 1;
break;
default:
BX_ERROR(("write counter in invalid write state."));
break;
}
if (thisctr.count_written && thisctr.write_state != MSByte_multiple) {
thisctr.null_count = 1;
set_count(thisctr, thisctr.inlatch);
}
switch(thisctr.mode) {
case 0:
if (thisctr.write_state==MSByte_multiple) {
set_OUT(thisctr,0);
}
thisctr.next_change_time=1;
break;
case 1:
if (thisctr.triggerGATE) { //for initial writes, if already saw trigger.
thisctr.next_change_time=1;
} //Otherwise, no change.
break;
case 6:
case 2:
thisctr.next_change_time=1; //FIXME: this could be loosened.
break;
case 7:
case 3:
thisctr.next_change_time=1; //FIXME: this could be loosened.
break;
case 4:
thisctr.next_change_time=1;
break;
case 5:
if (thisctr.triggerGATE) { //for initial writes, if already saw trigger.
thisctr.next_change_time=1;
} //Otherwise, no change.
break;
}
}
}
void pit_82C54::set_GATE(Bit8u cnum, bool data)
{
if (cnum>MAX_COUNTER) {
BX_ERROR(("Counter number incorrect in 82C54 set_GATE"));
} else {
counter_type &thisctr = counter[cnum];
if (!((thisctr.GATE&&data) || (!(thisctr.GATE||data)))) {
BX_DEBUG(("Changing GATE %d to: %d",cnum,data));
thisctr.GATE=data;
if (thisctr.GATE) {
thisctr.triggerGATE=1;
}
switch(thisctr.mode) {
case 0:
if (data && thisctr.count_written) {
if (thisctr.null_count) {
thisctr.next_change_time=1;
} else {
if ((!thisctr.OUTpin) &&
(thisctr.write_state!=MSByte_multiple))
{
if (thisctr.count_binary==0) {
thisctr.next_change_time=1;
} else {
thisctr.next_change_time=thisctr.count_binary & 0xFFFF;
}
} else {
thisctr.next_change_time=0;
}
}
} else {
if (thisctr.null_count) {
thisctr.next_change_time=1;
} else {
thisctr.next_change_time=0;
}
}
break;
case 1:
if (data && thisctr.count_written) { //only triggers cause a change.
thisctr.next_change_time=1;
}
break;
case 2:
if (!data) {
set_OUT(thisctr,1);
thisctr.next_change_time=0;
} else {
if (thisctr.count_written) {
thisctr.next_change_time=1;
} else {
thisctr.next_change_time=0;
}
}
break;
case 3:
if (!data) {
set_OUT(thisctr,1);
thisctr.first_pass=1;
thisctr.next_change_time=0;
} else {
if (thisctr.count_written) {
thisctr.next_change_time=1;
} else {
thisctr.next_change_time=0;
}
}
break;
case 4:
if (!thisctr.OUTpin || thisctr.null_count) {
thisctr.next_change_time=1;
} else {
if (data && thisctr.count_written) {
if (thisctr.first_pass) {
if (thisctr.count_binary==0) {
thisctr.next_change_time=1;
} else {
thisctr.next_change_time=thisctr.count_binary & 0xFFFF;
}
} else {
thisctr.next_change_time=0;
}
} else {
thisctr.next_change_time=0;
}
}
break;
case 5:
if (data && thisctr.count_written) { //only triggers cause a change.
thisctr.next_change_time=1;
}
break;
default:
break;
}
}
}
}
bool pit_82C54::read_OUT(Bit8u cnum)
{
if (cnum>MAX_COUNTER) {
BX_ERROR(("Counter number incorrect in 82C54 read_OUT"));
return 0;
}
return counter[cnum].OUTpin;
}
bool pit_82C54::read_GATE(Bit8u cnum)
{
if (cnum>MAX_COUNTER) {
BX_ERROR(("Counter number incorrect in 82C54 read_GATE"));
return 0;
}
return counter[cnum].GATE;
}
Bit32u pit_82C54::get_clock_event_time(Bit8u cnum)
{
if (cnum>MAX_COUNTER) {
BX_ERROR(("Counter number incorrect in 82C54 read_GATE"));
return 0;
}
return counter[cnum].next_change_time;
}
Bit32u pit_82C54::get_next_event_time(void)
{
Bit32u time0=get_clock_event_time(0);
Bit32u time1=get_clock_event_time(1);
Bit32u time2=get_clock_event_time(2);
Bit32u out=time0;
if (time1 && (time1<out))
out=time1;
if (time2 && (time2<out))
out=time2;
return out;
}
Bit16u pit_82C54::get_inlatch(int counternum)
{
return counter[counternum].inlatch;
}
bool pit_82C54::new_count_ready(int countnum)
{
return (counter[countnum].write_state != MSByte_multiple);
}
Bit8u pit_82C54::get_mode(int countnum)
{
return counter[countnum].mode;
}
void pit_82C54::set_OUT_handler(Bit8u counternum, out_handler_t outh)
{
counter[counternum].out_handler = outh;
}
Reference in New Issue View Git Blame Copy Permalink