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Merge pull request #912 from TomHarte/128kDecoding

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Corrects Spectrum 128kb partial decoding.
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Thomas Harte 2021-04-16 22:02:25 -04:00 committed by GitHub
commit 06cedb2e50
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 30 additions and 24 deletions
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28
Machines/Sinclair/ZXSpectrum/ZXSpectrum.cpp
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@ -355,6 +355,9 @@ template<Model model> class ConcreteMachine:
} }
break; break;
// Partial port decodings here and in ::Input are as documented
// at https://worldofspectrum.org/faq/reference/ports.htm
case PartialMachineCycle::Output: case PartialMachineCycle::Output:
// Test for port FE. // Test for port FE.
if(!(address&1)) { if(!(address&1)) {
@ -369,8 +372,10 @@ template<Model model> class ConcreteMachine:
} }
// Test for classic 128kb paging register (i.e. port 7ffd). // Test for classic 128kb paging register (i.e. port 7ffd).
if constexpr (model >= Model::OneTwoEightK) { if (
if((address & 0xc002) == 0x4000) { (model >= Model::OneTwoEightK && model <= Model::Plus2 && (address & 0x8002) == 0x0000) ||
(model >= Model::Plus2a && (address & 0xc002) == 0x4000)
) {
port7ffd_ = *cycle.value; port7ffd_ = *cycle.value;
update_memory_map(); update_memory_map();
@ -381,7 +386,6 @@ template<Model model> class ConcreteMachine:
// port values have taken effect. // port values have taken effect.
disable_paging_ |= *cycle.value & 0x20; disable_paging_ |= *cycle.value & 0x20;
} }
}
// Test for +2a/+3 paging (i.e. port 1ffd). // Test for +2a/+3 paging (i.e. port 1ffd).
if constexpr (model >= Model::Plus2a) { if constexpr (model >= Model::Plus2a) {
@ -398,24 +402,26 @@ template<Model model> class ConcreteMachine:
// Route to the AY if one is fitted. // Route to the AY if one is fitted.
if constexpr (model >= Model::OneTwoEightK) { if constexpr (model >= Model::OneTwoEightK) {
if((address & 0xc002) == 0xc000) { switch(address & 0xc002) {
case 0xc000:
// Select AY register. // Select AY register.
update_audio(); update_audio();
GI::AY38910::Utility::select_register(ay_, *cycle.value); GI::AY38910::Utility::select_register(ay_, *cycle.value);
} break;
if((address & 0xc002) == 0x8000) { case 0x8000:
// Write to AY register. // Write to AY register.
update_audio(); update_audio();
GI::AY38910::Utility::write_data(ay_, *cycle.value); GI::AY38910::Utility::write_data(ay_, *cycle.value);
break;
} }
} }
// Check for FDC accesses. // Check for FDC accesses.
if constexpr (model == Model::Plus3) { if constexpr (model == Model::Plus3) {
switch(address) { switch(address & 0xf002) {
default: break; default: break;
case 0x3ffd: case 0x2ffd: case 0x3000: case 0x2000:
fdc_->write((address >> 12) & 1, *cycle.value); fdc_->write((address >> 12) & 1, *cycle.value);
break; break;
} }
@ -476,15 +482,15 @@ template<Model model> class ConcreteMachine:
} }
if constexpr (model == Model::Plus3) { if constexpr (model == Model::Plus3) {
switch(address) { switch(address & 0xf002) {
default: break; default: break;
case 0x3ffd: case 0x2ffd: case 0x3000: case 0x2000:
*cycle.value &= fdc_->read((address >> 12) & 1); *cycle.value &= fdc_->read((address >> 12) & 1);
break; break;
} }
} }
if constexpr (model < Model::Plus2) { if constexpr (model <= Model::Plus2) {
if(!did_match) { if(!did_match) {
*cycle.value = video_->get_floating_value(); *cycle.value = video_->get_floating_value();
} }