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Edge up very close to video waits.

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I just need to implement back conversions that include marginal phase over in the JustInTimeActor.
This commit is contained in:
Thomas Harte 2021-06-27 16:28:01 -04:00
parent bdcab447f9
commit 1ea034310a
3 changed files with 43 additions and 20 deletions
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46
Machines/Enterprise/Enterprise.cpp
View File

@ -225,26 +225,38 @@ template <bool has_disk_controller> class ConcreteMachine:
using PartialMachineCycle = CPU::Z80::PartialMachineCycle;
const uint16_t address = cycle.address ? *cycle.address : 0x0000;
// TODO: possibly apply an access penalty.
// Calculate an access penalty, if applicable.
HalfCycles penalty;
if(is_video_[address >> 14]) {
// TODO.
} else {
switch(cycle.operation) {
default: break;
switch(cycle.operation) {
default: break;
case CPU::Z80::PartialMachineCycle::ReadStart:
case CPU::Z80::PartialMachineCycle::WriteStart:
if(wait_mode_ == WaitMode::OnAllAccesses) {
penalty = HalfCycles(2);
}
break;
// For non-video pauses, insert during the initial part of the bus cycle.
case CPU::Z80::PartialMachineCycle::ReadStart:
case CPU::Z80::PartialMachineCycle::WriteStart:
if(!is_video_[address >> 14] && wait_mode_ == WaitMode::OnAllAccesses) {
penalty = HalfCycles(2);
}
break;
case CPU::Z80::PartialMachineCycle::ReadOpcodeStart:
if(!is_video_[address >> 14] && wait_mode_ != WaitMode::None) {
penalty = HalfCycles(2);
}
break;
case CPU::Z80::PartialMachineCycle::ReadOpcodeStart:
if(wait_mode_ != WaitMode::None) {
penalty = HalfCycles(2);
}
break;
// Video pauses: insert right at the end of the bus cycle.
case CPU::Z80::PartialMachineCycle::ReadOpcode:
case CPU::Z80::PartialMachineCycle::Read:
case CPU::Z80::PartialMachineCycle::Write:
if(is_video_[address >> 14]) {
// TODO.
}
break;
case CPU::Z80::PartialMachineCycle::Input:
case CPU::Z80::PartialMachineCycle::Output: {
if((address & 0xf0) == 0x80) {
// TODO.
}
}
}

14
Machines/Enterprise/Nick.cpp
View File

@ -92,7 +92,17 @@ uint8_t Nick::read([[maybe_unused]] uint16_t address) {
return 0xff;
}
//int c;
Cycles Nick::get_time_until_z80_slot() const {
// Place Z80 accesses as the first six cycles in each sixteen-cycle window.
// That models video accesses as being the final ten. Which has the net effect
// of responding to the line parameter table interrupt flag as soon as it's
// loaded.
// i.e. 0 -> 0, 1 -> 15 ... 15 -> 1.
return Cycles(
15 ^ ((horizontal_counter_ + 15) & 15)
);
}
void Nick::run_for(Cycles duration) {
constexpr int line_length = 912;
@ -455,7 +465,7 @@ void Nick::set_output_type(OutputType type, bool force_flush) {
// MARK: - Sequence points.
Cycles Nick::get_next_sequence_point() {
Cycles Nick::get_next_sequence_point() const {
// TODO: the below is incorrect; unit test and correct.
// Changing to e.g. Cycles(1) reveals the relevant discrepancy.
// return Cycles(1);

3
Machines/Enterprise/Nick.hpp
View File

@ -23,11 +23,12 @@ class Nick {
uint8_t read(uint16_t address);
void run_for(Cycles);
Cycles get_time_until_z80_slot() const;
void set_scan_target(Outputs::Display::ScanTarget *scan_target);
Outputs::Display::ScanStatus get_scaled_scan_status() const;
Cycles get_next_sequence_point();
Cycles get_next_sequence_point() const;
/*!
@returns The current state of the interrupt line — @c true for active;