6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2024-07-05 10:28:58 +00:00
Code Issues Projects Releases Wiki Activity

Makes it optional whether the Z80 supports the wait line. If the wait line isn't in use, runtime costs are decreased because the optional wait cycles need not be iterated over.

Browse Source
This commit is contained in:
Thomas Harte 2017-08-26 23:08:57 -04:00
parent 97f57a3948
commit 57bfec285f
3 changed files with 19 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Machines/AmstradCPC/AmstradCPC.cpp
View File

@ -998,7 +998,7 @@ class ConcreteMachine:
}
}
CPU::Z80::Processor<ConcreteMachine, false> z80_;
CPU::Z80::Processor<ConcreteMachine, false, true> z80_;
CRTCBusHandler crtc_bus_handler_;
Motorola::CRTC::CRTC6845<CRTCBusHandler> crtc_;

2
Machines/ZX8081/ZX8081.cpp
View File

@ -332,7 +332,7 @@ class ConcreteMachine:
HalfCycles get_typer_frequency() override final { return Cycles(390000); }
private:
CPU::Z80::Processor<ConcreteMachine, false> z80_;
CPU::Z80::Processor<ConcreteMachine, false, true> z80_;
std::shared_ptr<Video> video_;
std::vector<uint8_t> zx81_rom_, zx80_rom_;

19
Processors/Z80/Z80.hpp
View File

@ -193,7 +193,7 @@ class BusHandler {
order to provide the bus on which the Z80 operates and @c flush(), which is called upon completion of a continuous run
of cycles to allow a subclass to bring any on-demand activities up to date.
*/
template <class T, bool uses_bus_request> class Processor {
template <class T, bool uses_bus_request, bool uses_wait_line> class Processor {
private:
T &bus_handler_;
@ -451,6 +451,7 @@ template <class T, bool uses_bus_request> class Processor {
// Allocate a landing area.
std::vector<size_t> operation_indices;
target.all_operations.reserve(number_of_micro_ops);
target.instructions.resize(256, nullptr);
// Copy in all programs, recording where they go.
@ -464,6 +465,12 @@ template <class T, bool uses_bus_request> class Processor {
continue;
}
// Skip optional waits if this instance doesn't use the wait line.
if(table[c][t].machine_cycle.was_requested && !uses_wait_line) {
t++;
continue;
}
// If an index placeholder is hit then drop it, and if offsets aren't being added,
// then also drop the indexing that follows, which is assumed to be everything
// up to and including the next ::CalculateIndexAddress. Coupled to the INDEX() macro.
@ -795,6 +802,13 @@ template <class T, bool uses_bus_request> class Processor {
while(!isTerminal(source[length].type)) length++;
size_t pointer = 0;
while(true) {
// TODO: This test is duplicated from assemble_page; can a better factoring be found?
// Skip optional waits if this instance doesn't use the wait line.
if(source[pointer].machine_cycle.was_requested && !uses_wait_line) {
pointer++;
continue;
}
destination.emplace_back(source[pointer]);
if(isTerminal(source[pointer].type)) break;
pointer++;
@ -955,7 +969,7 @@ template <class T, bool uses_bus_request> class Processor {
bus_handler_.flush();
return;
}
if(operation->machine_cycle.was_requested) {
if(uses_wait_line && operation->machine_cycle.was_requested) {
if(wait_line_) {
scheduled_program_counter_--;
} else {
@ -2002,6 +2016,7 @@ template <class T, bool uses_bus_request> class Processor {
Sets the logical value of the wait line.
*/
inline void set_wait_line(bool value) {
assert(uses_wait_line);
wait_line_ = value;
}