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[Re]discovered that sync may also be a product of the interrupt cycle. So started looking into that.

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This commit is contained in:
Thomas Harte 2017-06-04 21:54:55 -04:00
parent 7f743c6fb0
commit 7e3a46c33e
2 changed files with 22 additions and 10 deletions
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27
Machines/ZX8081/ZX8081.cpp
View File

@ -11,7 +11,8 @@
using namespace ZX8081;
Machine::Machine() :
vertical_sync_(false),
vsync_(false),
hsync_(false),
ram_(65536) {
// run at 3.25 Mhz
set_clock_rate(3250000);
@ -23,24 +24,26 @@ int Machine::perform_machine_cycle(const CPU::Z80::MachineCycle &cycle) {
uint8_t r;
switch(cycle.operation) {
case CPU::Z80::BusOperation::Output:
if(*cycle.address == 0xff) {
update_display();
set_sync(false);
if((*cycle.address&0xff) == 0xff) {
set_vsync(false);
}
break;
case CPU::Z80::BusOperation::Input:
if(*cycle.address == 0xfe) {
update_display();
set_sync(true);
if((*cycle.address&0xff) == 0xfe) {
set_vsync(true);
}
*cycle.value = 0xff;
break;
case CPU::Z80::BusOperation::Interrupt:
set_hsync(true);
*cycle.value = 0xff;
break;
case CPU::Z80::BusOperation::ReadOpcode:
set_hsync(false);
// printf("%04x\n", *cycle.address);
r = (uint8_t)get_value_of_register(CPU::Z80::Register::R);
set_interrupt_line(!(r & 0x40));
case CPU::Z80::BusOperation::Read:
@ -113,8 +116,16 @@ void Machine::update_display() {
cycles_since_display_update_ = 0;
}
void Machine::set_sync(bool sync) {
void Machine::set_vsync(bool sync) {
if(sync && !vsync_) printf("\n---\n");
vsync_ = sync;
}
void Machine::set_hsync(bool sync) {
if(sync && !hsync_) printf("\n");
hsync_ = sync;
}
void Machine::output_byte(uint8_t byte) {
printf("%02x ", byte);
}

5
Machines/ZX8081/ZX8081.hpp
View File

@ -50,11 +50,12 @@ class Machine:
std::vector<uint8_t> zx81_rom_, zx80_rom_, rom_;
std::vector<uint8_t> ram_;
bool vertical_sync_;
bool vsync_, hsync_;
int cycles_since_display_update_;
void update_display();
void set_sync(bool sync);
void set_vsync(bool sync);
void set_hsync(bool sync);
void output_byte(uint8_t byte);
};